/diy/ - Do It Yourself

Good work, anon.

Let's follow up with the pasta:

https://pastebin.com/9uYXMhVm

>>1333382
FWIW Previous thread:
>>1327446

Current data on propagation is here: http://wsprnet.org/drupal/wsprnet/map

Online SDR's networks: websdr.org sdr.hu

Learning morse code: lcwo.net www.justlearnmorsecode.com

>>1333382
Anyone interested in DIY upconverter for RTL-SDR made almost entirely using junk parts (like two energy saving bulbs, a VGA or DVI cord, few transistors / resistors / caps from a mother board, and xtal resonator from a HDD)?

>>1333399
that sounds just sick enough to work

Whats the fun of ham radio? I've been curious about it, but never saw the fun/application of the knowledge

>>1333417
>Whats the fun of ham radio?
it's just like audiophiles but with radio

>>1333417
for many, including myself, it's an extension of an electronics hobby. if you aren't into battling the laws of physics and the sky to send a few microvolts of signal over vast distances, ham radio may not be very entertaining to you

>>1333421
also less gold plating and more math

>>1333417
It is tech and social

Social
- chat with people all over the world
- collect QSL cards
- long distance work (DX)
- master high speed morse (can be pretty impressive!)

Tech
- make you own equipment, explore new designs (with a license you are allowed to make high voltage gear that would incinerate an elephant)
- antenna design - you would be surprised how much effort can be put into this
- new communication forms, especially digital modes with fancy modulation
- explore MIMO, beam forming etc
- new ways of direction finding (DF)
- explore digital signal processing (DSP) algorithms for radio
- see how far you can communicate with as little emitted power as possible (also impressive results)
- locate noise sources

>>1333421
>it's just like audiophiles but with radio
And you can actually measure how good is your radio / how powerful is your amplifier / how big is your antenna.

Alas you can't do anything reasonable when you are to compare audiophile devices. Generally the more bling, the higher the price tag is the better and that's it.

audiophile: I got this hand-made single-endend dual mono class-A tube amplifier for $20 000, it has THD of mere 10% while delivering whopping 15 W and sounds awesome, you can't beat tubes.

ham fag: guys I've built a tube amplifier with two 813 and junk parts, it delivers 700W into my dummy load, check out my signal. Is there any splatter? You ARE 50 dB over 9, I repeat, 50 dB over 9! What antenna are you using? My antenna is 6 element yagi, 40 meters over ground.

>>1333412

>>1333464
My QTH is noisy as hell

>>1333465
Most of the time all short-wave bands are filled with various noise and all I can get is various short-wave broadcasting stations, once it gets quiet and conditions are right I can receive hams up 5000-7000 km away. I recon it's extremely good for a $20 RTL dongle and shit I pulled from junk computer HW. My antenna is about 15 m long wire out of my window to the nearest tree.

>>1333390
And the thread before that :
>>1298149

>>1333470
If you use a loop antenna you can put the null towards the worst noise source.

>>1333465
I live 0.5 miles from a commercial AM Transmitter that causes harmonics/splatter across the entire HF spectrum. I hear them about every 30 kHz between 160 and 30 Meters.

Sample from my RSP2 wired into my TS-590SG's DRV/Ant out. Every line is a 5000 Watt AM station belching out Mexican music that is bleeding onto all the other bands.

FCC won't do shit about it even though it's an American station and every other ham in the ares (6 or 7 of us effected by this) has filed a complaint.

If ham radio was such a blast
why are you in here posting this crap to people that could careless?
You Hamrods make up about .0000001 of the populous...in short fuck off

>>1333470
what program is this and how do I kill myself after I dwnld it?

>>1333531
You cared enough to post here so what is your problem?

>>1333547
Don't respond to this troll. He's mucked up the last two threads. Let him come in and whine because he's too poor to afford a rig and too stupid to pass his Tech but don't egg him on.

>>1333470
>15 m long wire
You have a random wire not a long wire.

>>1333399
Definitely. I hate listening to only FM when GQRX keeps waving its SSB function in my face.

>>1333616
Is there some way to have a variable length SW antenna that's easy to change? All I can think of is a cable above your antenna with a pulley on it that you can use to pull a brush nearer or further.

(/diy/ should have doodles like /vip/)

>>1333650
sure, tie a rope to the far end of your antenna wire
also, placing an inductor in a strategic location in your antenna can make it electrically longer
finally, consider the pa0rdt active mini-whip©

Radio paste updated: https://pastebin.com/gva3gn2H
Written in Markdown but I don't have a pro account.

>>1333399
Post the actual thing rather than screenshots please.

>>1333536
Which one?
On background there is hdsdr, http://www.hdsdr.de/hardware.html
On foreground there is fldigi, https://sourceforge.net/projects/fldigi/ running in weather fax mode.

>>1333616
It's 15m long random wire, matched with 1:9 unun.

>>1333739
Perhaps you mean a 9:1; unless you are transmitting with it I wouldn't worry too much about matching it.

>>1333507
I tried, but there is noise in all directions and it's much stronger. The best option for now is a wire from the window to the three. Noise sources are somewhere in the building.

I plan to build OCFD on the roof, however it would be unlikely possible to mount it high enough, hopefully I'll be able to mount it 2-3m high.

>>1333755
Geeze, and I ( >>1333520 ) thought I had it bad.

>>1333756
Often it's much worse than that, here is overnight recording. 160m is unusable completely, 80m is full of noise and only local hams can make it (like few kilometers away), so it's unusable as well, only 40m is somewhat better as sometimes you can find a noise-free spot.

I also have FM radio/TV tower within like 2 miles away, well I have extremely strong FM & TV signals here, so strong that shit makes measuring RF stuff tough due to interference and it also rules out many if not all active antennas due to intermodulation distortion of preamps (I build two active loop antennas, all performed shitty, not only they pick up local noise but also TV & FM transmitters generate shit load of interference everywhere).

>>1333750
>Perhaps you mean a 9:1; unless you are transmitting with it I wouldn't worry too much about matching it.
It's 1:9, 1 side goes to coax, 9 side goes to wire. I also tried 1:4 and 1:16, 1:9 seems to be the best overall.
http://www.dl1glh.de/beverage-unun/beverage-unun.html

>>1333773
Try some ferrites near the antenna in. Maybe a current choke just before the feed point.

>>1333778
I have plenty of them installed, at this moment my set up looks like that:

- Wire
- Un-un
- common-mode choke within 2" after un-un, wound on high-perm 2" toroid, to attenuate low frequency noise
- another one within few inches after the first one, made with 2 low-perm ferrite beads sourced from VGA cable, to attenuate HF and VHF noise.
- 7 meters of coax cable.
- 1-to-1 RF transformer (for galvanic isolation, as I connect RTL-SDR to my laptop and laptop isn't grounded, and to further increase common-mode RF isolation).
- 2 MHz Cheb 1db 5th order highpass (will replace it with 7th or 9th order with 3-3.2 MHz high-pass as it's not enough, I clearly see shit load of noise and AM stations down low), followed by 22 MHz Cheb 9th order (had 7th order, still had FM and TV shit here and there).
- Up-converter has ferrite beads on both input and output coax cables, also it's battery powered.
- DIY USB cable for RTL-SDR which has two high-perm toroids installed as common-mode chokes to attenuate RF noise generated by laptop (one at each end). I had to do that as I found that the cable that I used had shitty shield-to-connector housing connection (intermittent 5-100 ohms) and adding a toroid to USB cable noticeable attenuates RF noise, even on 70cm band).
- Up-converter and up-converter battery and filters go to metal enclosure to help with RF pick up (ATX power supply).

I'm not paranoid, all that amount of chokes and filters were introduced during many tests and trials.

>>1333798
I think you need a couple more chokes on there. Maybe, make an antenna purely out of chokes and wound cores.

>>1333803
Not him, but I live right behind a block of stores that all have CFLs and radio-unfriendly LEDs.

If I could cover my LMR-400, all 85 feet of it, in ferrites, I would.

>>1333803
You are clearly underestimating what cheap chinese electronics (including CFL and LED's lights) can do.

There are individuals who are obsessed with cheap as hell devices from aliexpress & ebay, most of chargers (including chargers for vapes), CFL/LED's SMPS have virtually no EMI filters installed.

No decent EMI filters + connection to mains = decent antenna and decent wideband noise source.

Well shit, that wasn't etch-resistant.

>>1333382
I'm curious about using an RTL-SDR in a vehicle to scan for and log activity on different bands. I travel a lot and I'm interested in getting a transceiver in my vehicle preferably operating on some or all of the 10 meter/6 meter/2 meter/70 cm amateur bands (seeing as how that would give much more coverage than a CB radio), but have heard complaints about those bands being rather dead these days in many areas so before I do all the research and invest in a good radio for my vehicle I'd like a cheap way to scan first to avoid potential disappointment.

My goal is to be able to generate a log of activity as I drive around to various areas and I figure doing this by simply saving a recording of the waterfall display that I could quickly page back through later and look for signals on would be enough (since any sort of audio recording would likely get very large). I would likely have it hooked up to an old laptop I have laying around, though I may consider an SBC for the task. I also figure I could do the same for CB activity both for comparing to the amateur radio activity and for seeing if it would be worth it to invest in a CB radio capable of doing SSB if those amateur bands really are as dead as I've heard people say they are.

Has anyone set up an RTL-SDR for this task before and would there be a more effective way of doing this?

>>1333924
Steal some nail varnish from your wife / gf. Or make yourself a cutter from hacksaw blade.

>>1333926
It it's well up to the job for 2M & 70cm bands, it will even work on 23cm band (at least R820T/R820T2 tuners do).

It will also work on 10M and CB bands, but sensitivity is slightly.

Don't forget you need a real antenna, the one that's bundled is sub par for desired bands (it will work and it will pick up strong signals though).

>>1333926
>Has anyone set up an RTL-SDR for this task before and would there be a more effective way of doing this?
Also you can get a used scanner and then sell it for about the same price.

>>1333939
>Don't forget you need a real antenna, the one that's bundled is sub par for desired bands (it will work and it will pick up strong signals though).
I was planning on using a magnet antenna, then going with a more permanent mount when I settle on exactly what I'd be getting. I know having the antenna inside the vehicle is a bad idea.

>>1333941
>Also you can get a used scanner and then sell it for about the same price.
Can those scan small ranges of frequencies or just pre-programmed channels? I was considering the RTL-SDR and saving a recording of the waterfall display because I'd still be able to see activity outside of commonly used simplex channels/publicly listed repeaters.

>>1333962
>Can those scan small ranges of frequencies or just pre-programmed channels? I was considering the RTL-SDR and saving a recording of the waterfall display because I'd still be able to see activity outside of commonly used simplex channels/publicly listed repeaters

You can record 2 MHz range with RTL-SDR.

WRT scanners you generally can program them to scan frequency range. Some scanners have two independent receivers so you can monitor 2m & 70cm at the same time.

>>1333756
I can see why SOTA is popular.

>>1333853
>You are clearly underestimating what cheap chinese electronics (including CFL and LED's lights) can do.
Around here cheap LED and electronics brought down the aircraft communication bands and the authorities moved in on the case. This was one huge installation with several walls covered in LED so it was a more distinct DF target.

The normal case is a dozen sources in homes, shops, office buildings etc and all over the place so these are hard to localise. Given a 20 year lifetime for LED we will have a problem for several decades. And given nothing serious is being done short of single instances the problem will most likely continue to grow for another decade by which time GSM/LTE/TETRA/DAB/TV will be deep in a radio fog.

>>1334141
>cheap LED and electronics brought down the aircraft communication bands
where was it?

>>1334133
>I can see why SOTA is popular.
I'm seriously contemplating about getting a portable transceiver and a tent. Basically if I install an antenna on the roof and get only marginal improvement in noise floor I'll have no choice except going portable.

>>1333382
I think 404 would be a good look, and this post will contribute to that.

>>1334144
>where was it?
Trondheim in Norway, Værnes is the local airport. Rockheim, a rock music museum was equipped with 325 power supplies for 13500 LEDs that jammed bands from 20 MHz to 300 MHz.

You might want to feed the following through Google Translate:
https://nelfo.no/Bibliotek/Nyhetsarkiv/2014/Oktober/Rockemuseum-forstyrret-flytrafikken/
https://www.tu.no/artikler/eksplosjon-i-piratsendinger-pa-fm-bandet-slik-sporer-myndighetene-opp-fm-entusiastene/430745

>SOTA
I live in a rural area but next to one of the very largest centrals for the high voltage power distribution backbone system. More than 10 separate pylon carried 3 phase lines meet in this nexus. So it will be a longer hike into the mountains to get a decent signal.

>>1334141
power supplies could in principle be retrofitted independently of the LEDs, if separate, as would generally be the case in LED tape used in signage. maybe sending someone in with a bucket-o-ferrites would be enough
otherwise I guess we'll all be using DSSS modes before long

i see a lot of ferrite beads online, but what would be a good place to look for ones that are decent and cheap in price? people seem to be complaining about the ones sold on amazon

>>1333700
I updated the Radio FAQ. Since I don't have a Pro membership at Pastebin I have instead placed the document on an open FTP site:
ftp://collectivecomputers.org:21212/Books/Cyberpunk/Tech/Radio/radio_FAQ_Preview2.htm
password and user is guest



>>1334387
ive never used pastebin, whenever i make a thread, (HRG, SKYKANG) i usually just copy and paste.
i really wish /diy/ had IDs, so i could tell who we are having a dialog with

i would also like to post pictures of my setup/antennas, but am unsure how to take the data off of cell pictures.
if anyone knows......
running linux if that helps

>>1334481
Use your phone to post?

>>1334505
i guess i could do either one. im pretty sure there is location data on there, but im not sure how to get it off. not to good with the computers, but im learning

>>1334512
I connect my phone to home WiFi and upload pics that way.

>>1334481
>but am unsure how to take the data off of cell pictures
the absolute STATE of americans

>>1334517
i know how to do upload pics. i just want to know how to strip data off the pictues

>>1334521
not american. im just learning about computers. im just getting into it. instead of being a cunt some help would be nice. its all something new to me

>>1334525

>>1334525
4chan strips all of the extra data from pics on its own. Try find one pic here with one

>>1334525
they're just busting your balls because they don't know how. Irfanview will set up the exif data anyway you like, but you have to run it in wine.

if you're extra paranoid, resize the pic to destroy any steganography.

>>1334556
You can install ImageMagick and do whatever you want with metadata and exif. However these days it's not needed, 4chan strips metadata on its own.

>>1334556
thanks good sir. i havent used wine yet, but its clearly something im going to have to start using. ive installed debian and ubuntu so far (debian i like a lot more) but its fun to mess around with so far. thanks for the info
>>1334571
ah, i have that already. was trying to use gimp, but that seemed like a lot to learn. thanks m8.
how does it strip the data? do a lot of sites do that? sorry for stupid questions, as im trying to figure this out. having a lot of fun with linux though. a far jump from the windows ive used in the past

>>1334580
imagemagick has "convert" utility that can do wonders. Works like that (that's a console command):

convert -strip image.jpeg

>>1334580
>do a lot of sites do that?
Nope, many sites leave images as is. 4chan started to strip metadata a while ago, to keep users safe.

>>1334545
>>1334571

>letting 4chan harvest your exif data

strip it before you post it
Screenshot your photo and make a jpg out of it using paint, takes 2 seconds you should be cropping shit out anyways

>>1334589
ok thanks. im trying to learn using the command line. seems extremely useful, but unforgiving.
>>1334591
yeah, i dont need them getting anything from me, not that im important, just principle.just screenshot it in imaginemagick? and i usually crop everything. thanks in advance

>>1333968
>You can record 2 MHz range with RTL-SDR.
This is more of what I was looking at doing, since I'm not interested in voice I can record significantly more than 2 MHz:
http://kmkeen.com/rtl-power/

I figure I'll have a laptop or an SBC that I'll start up when I get start my vehicle, and I can then have it scripted to start recording as soon as it boots up and continue until I reach my destination and shut it off.

>>1334478
FAQ dude here.
>i could tell who we are having a dialog with
The document is free to edit for anyone so it is not important who I am. And if you have contributions but don't want to edit the HTML, I'll be happy to do the editing.

>>1334675
>>i could tell who we are having a dialog with
No you can't.

>>1334598
>ok thanks. im trying to learn using the command line. seems extremely useful, but unforgiving.
Nah it's easy to use command line in linux/unix. Much easier than in DOS. I can vouche for that, I'm working with *nix since ~2001 (also my main OS is Gentoo and my Laptop is Thinkpad, can you guess what am I doing for a living).

> for i in *.jpg; do convert -strip "$i"; done

- runs "convert -strip " command for all .jpg files in current folder.

>>1334774
>(also my main OS is Gentoo, can you guess what am I doing for a living).

sure. you are an autistic sperglord?

>>1334832
Software engineer who is mostly working with open-source stuff. With Gentoo you can easily rebuild every single package, patch and debug every single package, and that's not limited to the native cpu arch. You can easily build a tool chain using various libc, compiler versions, then build test apps, etc. Comfy as hell. I tried business laptops from different brands like Acer but they are too flimsy, if you travel a lot and need a workhorse that survives multiple falls on concrete floor then you need a Thinkpad.

>>1334774
i would like to try gentoo but i think im a bit aways from that. i have a thinkpad, but its old and has the "pencil eraser' as the mouse. been thinking what distro i could put on there.
could you suggest a place to learn using command line? i was being stupid with my last install, and totally messed up everything, it wouldnt let me even upgrade or update, no clue what i had done.
everything i seem to look up is for ubuntu, and im pretty sure they have different commands
i gotta say, this is so much more fun than using windows.

>>1334925
>i would like to try gentoo but i think im a bit aways from that.
It's kind of pointless unless you are a developer and you *NEED* quick access to source code & option to rebuild packages & control various build options. It would be surely fun but it will be frustrating 95% of the time.

>>1334925
>been thinking what distro i could put on there.
Any binary distro will do, just configure it to use some lightweight desktop environment by default (like xfce). Don't use kde or gnome.
>>1334925
>could you suggest a place to learn using command line?
Unfortunately nope... It all started back in early 90's, I was working with MS-DOS running on a 486. I started with manuals and experiments. Nowadays you can google whatever question you have and find an answer. Linux users group is much bigger than it was 15-20 years ago.
>>1334925
>i was being stupid with my last install, and totally messed up everything, it wouldnt let me even upgrade or update, no clue what i had done.
Not a big deal, start again from scratch. I fucked installations many-many times. Pay attention and what you are doing, what repos are you selecting, etc.

Also this isn't the best board or thread to discuss Linux and stuff. Generally going off topic is frowned upon.

>>1334770
Look up stylographic analysis.

Hams can recognise others on CW by their fist, but I cannot see any software that does such analysis.

>>1334675
>>1334770
i was speaking about this board, sorry for confusion

>>1334591
Paranoid a bit? Maybe I should sketch my photo, take a picture of the sketch, display the photo of the sketch on my TV, take a picture of the TV screen, then open it up on the computer take a screen shot, edit the screenshot, watermark it, and save it as a highly compressed jpg.

>>1334603

>>1334980
id like to uncompress something against your anus, if you know what i mean

>>1334962
>but I cannot see any software that does such analysis.
it's the kind of thing you'd train a neural network for, same way stuff like image recognition is done

>>1335017
Back in the day when I learned Morse code I was surprised how quickly I learned to recognise all my colleagues, even at a stage when I was still a bit shaky.

I was also told a lot of stories from WWII where intelligence operators on both sides learned to recognise the fists independent of their call signs. We also learned some counter means but even that would be penetrated after a while by a skilled int. op. And I did meet a lot of skilled people.

So, how then do you train a neural network without getting their call signs into the mix?

>>1335012
Could you spell it out for me?

>>1334580
>was trying to use gimp
when you export a jpg, in the quality dialog, under advanced,turn off EXIF and XMP

>>1334832
nice work if you can get it

>>1335092
edit out call signs in the samples
anyway, Tx fingerprinting also has its place and may be easier to automate

>>1335115
>edit out call signs in the samples
That is a minimum, yes. I often hear sloppy fists during CQ.
>anyway, Tx fingerprinting also has its place and may be easier to automate
That is used against radars, especially where tube power amplifiers are in use. I am not sure it can be used against solid state radios or their PA stages without also seeing biasses due to impedance mismatches.

Having a nice QSO with a Mexican station on 7.195 and then "Captain Dave" comes on and interrupts (of fucking course). Wish that fucker would just stick to 3.850.

>>1335142
tell that old faggot to shut the fuck up

>>1335149
I just 73'd, signed and spun the big knob like the FCC says to do. Laura Smith is fucking useless.

>>1335151
>She also said the FCC is more aggressively policing the Amateur Radio bands, and she cited the case of an unlicensed individual in New York, who was arrested and assessed a fine for interfering with Amateur Radio repeaters as well as with public service communication systems.

but she arrested ONE person! so helpful!

>>1335153
She needs to arrest/seize the equipment of AC1DD, K1LEM, KI4THY and K9RSY... Especially Dan and Gary, figure out who the CBer who goes YEE-HEE-HEE all the time is, and fine all the fucking QRMers.

>>1335158
the only reason they went for that guy was because he was jamming cop frequencies.
nothing will be done about dan or those other retards, unless we go cut their coax ourselves

>>1335158
>AC1DD
Ham radio = 4chin for old men?

>>1335164
14.313, 7.200 and 3.850(?) are /b/ before there was /b/.

>>1335164
They don't call him "Double Dildo" for nothing.

>>1335175
And he's on, being a dildo now.

typical hammer in his "lair"

>>1335123
a team from Bell Labs used frequency domain info to distinguish between 8 USRP boxes sending identical GSM preambles with >95% success at 30dB S/N, 67% at 0dB S/N
fascinating reading with recaps of the state of the art ten years ago. apparently key-down transients were quite telling
https://www.bell-labs.com/usr/milind.buddhikot/www/psdocs/cogfemto/VTC%20Falls%202008.pdf

>>1335164
affirmative

It's kinda cool to see all the chatter and excitement here over ham radio subject. I never thought 4chan (granted it's the DIY board) would have been a place where hams would congregate. Aside from the "maker movement" within the last 5 years, why has ham radio seen a recent resurgence?

I think the home PC market in the 80's pulled a lot of hams into the PC hobby for many years. Now that PC's are freaking everywhere, the novelty of being a computer geek has worn out, and PCs are no longer fascinating and unique.
I personally think cheap RTL-SDR had a lot to do with it. It fascinated a lot of tech savvy PC geeks. It seems ham radio is now the haven for all the tech savvy people to congregate. I dunno, just my theory.

>>1335269
>why has ham radio seen a recent resurgence?
a) drones
b) TSHTF
c) the death of le social networking maymay
d) all these choices are correct

>>1335269
We have several "technology nets" in my area. The younger hams (usually only Tech-class) really love PSK31, RTTY et al and really love experimenting with antennas ans well as Echolink and satellite beacon chasing. The older dudes (usually Extra-class) are more about Work All States and contesting.

I just bought an rllsdr and this antenna. Going to poke around and listen for a while before I get my license. Any stations I should check out first?

>>1335307
Really depends on what you want to listen to. Try to get it as high as possible, though. If you have a tree with a branch you can throw a rope over and pull it up into, that would be great. Discones have great reception.

Police bands will either be in the 140-50, 430-50, or 800 MHz higher bands.

International broadcasting happens in 3 kHz to 30 MHz as well as ham broadcasting.

>>1335312
>International broadcasting happens in 3 kHz to
There are no broadcasts lower than 100-150 kHz.

If you are interested in long range stuff then you have to listen to LW/MW/HF. VHF/UHF is for local communication mostly.

>>1335318
I spaced. Meant to write 0.3 MHz. I think my brain on scotch make fingers work funny.

>>1335318
Fun fact:

https://en.wikipedia.org/wiki/List_of_VLF-transmitters

>Not that he will hear any of those with that antenna.

>>1335357
I used to live right near Project Sanguine. Our TV would lose picture when that thing fired.

I wounder how well my G5RV hooked to my RSP1 would receive NAA.

Might try it tomorrow when I'm in the shack.

What is the worst SWR I can operate at 100 watts with on an IC-7300? I cannot get my antenna (EMCOMM on a 9:1 Unun) to tune less than 3:1 on 80 Meters. Really want to talk on 80 and just want to know if 3:1 is okay enough.

>>1335385
>Project Sanguine
My grandad had property within few miles of military base with over-the-horizon radar installation. It killed everything, both TV & AM radios. Good thing they didn't operate it 24/7.

>>1335430
Check the manual and/or build yourself 1:16 unun.

I made an UN-UN with windings commutated by 2 relays and I can change select 1:4, 1:9, 1:16 remotely. Do you need a schematic for that?

>>1335434
Please. I can get the SWR to 3:1 but nothing better and the manual doesn't say if it's safe for the finals or not. The only activity I hear when I fire up my rig that I want to talk to is on 80-75 Meters but I'm afraid to burn my finals if my SWR is out of a safe range for the rig. I'm willing to try anything to get to even 2:1.

>>1335443
will post in few hours

>>1335451

>>1335443
I did some calculations, 100 W @ 50 Ohm is 70.5V RMS, or 100V ampliude or 200V peak-to-peak. Obviously voltage would be 4 times more than that after 1:16 un-un and you would need decent HF relays to commutate that. It's kind of impractical.

Can you share more info on your antenna configuration and your set up?

>>1335530
I'm using attached set up with QRP DIY rig.I use 250VAC / 10A relays.

For 100W I'd think you have to use 400VAC relays.

>>1335534
It's possible to add a 1:4 unun in series (near antenna feed point and check if that helps with SWR).

i tried ununs using binocular cores and toroids for unnus, binocular cores seems to be more efficient and have wider bandwidth. You can try using 2 or 4 ferrite beads salvaged from VGA/DVI cables if you don't have anything at hand

>>1335537
BTW you can also try to add fourth winding to your unun. No relays no extra stuff, just one wire.

>>1335430
Sure, just make sure you know where to pick up some spare finals.

>>1335443
> I'm willing to try anything
Really . . .

>>1335430
>EMCOMM on a 9:1 Unun
Seriously though, what kind of antenna? If you are running a wire (since you're using an unun) try extending it or making it shorter. You might also try using a counterpoise cut for 80.

First Thunderstorm since I got my rig is coming. I've disconnected my antenna, but should I also disconnect the rest of my equipment from the common ground?

>>1335812
might as well. dont want to fry anything

>>1335835

RF fags. If you were to analyze the characteristics of an RF signal in order to mimmick it what would you use in conjunction with a pc?
Antennas, RF modules, software, etc. Im new to this.

>>1335948
Something like an SDR dongle ($30) or HackRF ($300) with an antenna (size depends on what you want to listen to) with HDSDR software will let see the signal and record it on your computer. Please don't do anything illegal with this info.

>>1335948
what frequency?

>>1335906
youve broken one!

>>1335963
Between the 300 and 450 MHz approximately.

>>1335962
thx

>>1335972
300 to 450 is a pretty wide. The wavelength of 300 is about 1 meter while 450 is closer to 67-68 cm. For reception, your length doesn't matter (I'd suggest a full meter antenna; piece of copper wire is fine, as high as you can get it) but length is very important in broadcasting. Also whatever signal you want to listen to, try to match the polarity (if their antenna is vertical, make your vertical, if it's horizontal, make your horizontal) for best signal reception.

>>1333382
Anyone runs OCFD antennas?

I'm looking into building one.

Also share your thought on dipole-like multi-band antennas, I'd like to have 80 m, 40 m & 20 m bands.

>>1333932
Looking fabulous already!

>>1336019
You can use exacto knife to make edges prettier.

Also you can use scotch / electrical vinyl tape for patterns like that.

>>1336019
And no problems. The pen was noticeably more delicate than the nail polish though. A ball-point pen full of nail polish would be perfect for getting those edges nice.

>>1336027
Not sure how easy this stuff would be to cut off, it adheres to the copper pretty powerfully. I considered electrical tape, but my rolls are a bit too flimsy and flexible.

>>1336043
I said no problems.

>>1336043
>Not sure how easy this stuff would be to cut off, it adheres to the copper pretty powerfully
That's what acetone is for anon.

>>1336052
I can't add acetone to just that one part of nail polish I want to cut off and not effect the rest of the board, unless I'm misunderstanding why he mentioned an exacto knife in the first place.

But anyway, here's the traditional PA0RDT Mini Whip PCB done, and sadly enough it's my best PCB yet. That is if you exclude the scrap of copper I had to scratch out of the gap between two pads with a screwdriver. I'll put this project on hold for a bit, but now that I've got the PCBs for this and the power unit made I can finish it at my university accomodation without access to etchant and disposable tablecloths (RIP).

>>1335994
I have a OCFD. Mfj 40 meter. Works great! No issues, but I use a tuner.

>>1336076
Oh and before that I'll need to make a simple upconverter if I want to use my cheap SDR for SW.

>>1336043
>Not sure how easy this stuff would be to cut off, it adheres to the copper pretty powerfully.
You first do a good cut along the edge then scrape the extra. It's easier to do when the varnish is semi-dry.

If you go with scotch / electrical tape route, then you first cover the whole board with tape, then cut islands, then lift extra strips with tweezers.

>>1336077
Can you share links / model of the antenna and the tuner? How high is the antenna?

>>1336080
Is this what I should be looking at? Or do you lot like actual diode ring mixers? I'd probably optimise a few filter/oscillator settings on it since my SDR picks up 26MHz and above, but I can't see any other things I'd need to change.

>>1336087
Oh and what's the lowdown on inductors for RF? I see a lot of them use hand-wound toroids, which is fine since they're half in the nH range, but they're definitely a lot larger than axials or radials(?), which I see a couple of now and then, specifically I've seen the mini-whip's power feed unit made with axial inductors in images I've seen. I imagine this is fine because it's being used to filter power and it doesn't affect the signal much if at all, but I guess the same doesn't hold for filter inductors? I hope I can also use my bargain-basement 50V ceramics for RF.

>>1336087
NE602 has lower dynamic range and more noise than diode ring mixers do. However you can use NE602/NE612/TA7358/LA1185 with simple up converters, they work just fine and easy to use. Build something that you fully understand so you troubleshoot it and make it work.
I personally used high-level diode ring mixers and H-mode mixers using bus-switchers. Check PA3AKE pages if you need more info on that topic.

>>1336087
>I'd probably optimise a few filter/oscillator settings on it since my SDR picks up 26MHz and above, but I can't see any other things I'd need to change.
You absolutely need to add a high-pass filter. Noise level at VLF/MW bands is too damn high (even in rural areas) and it would likely overload your up converter, introducing a lot of spurious signals to higher bands.
For a start I suggest to use something like 3MHz high-pass followed by 15-20MHz low-pass. You can calculate filters there: http://www-users.cs.york.ac.uk/~fisher/lcfilter/ or download "Elsie". I use air-coil calculator that comes with "minikernRechner" tool, it's pretty much spot on (generally better than ±10%).

I suggest to use LO running at least two times higher than corner frequency of low-pass filter you are using.

>>1336091
>Oh and what's the lowdown on inductors for RF?
Inductor for filters: either air core or powdered iron toroids.
Generally axial/radial inductors with ferrite cores aren't suitable for RF filters, they are fine for various chokes.

>>1336091
>I hope I can also use my bargain-basement 50V ceramics for RF.
NP0 will do, X5R/X7R/Y5Z/etc aren't suitable for filters.

>>1336110
>NP0 will do, X5R/X7R/Y5Z/etc aren't suitable for filters.
I meant RF filters.

>>1335812
>E0A01: What is the primary function of an external earth connection or ground rod?
>lightning protection
you'll be fine, anon

>>1335976
>implying anon isn't just trying to replay a key fob transmitter
lewl

>>1336091
toroids allow for better Q due to lower losses, iirc

>>1336119
NP0 are named for their near-zero temperature coefficient. you don't want capacitors in tuned circuits drifting due to temperature variations

>>1336123
>you don't want capacitors in tuned circuits drifting due to temperature variations
That's not the major issue with x5r/x7r/y5z capacitors in tuned RF circuits.
These are usually extremely non-linear devices, the capacity can drop about 10 times at rated voltage. Non-linear capacity-vs-voltage characteristic implies there will be extra frequencies generated in RF circuits, basically filters would generate "new"/extra signals on their own. Also these kinds of capacitors are usually pretty lossy devices (low Q).

https://www.maximintegrated.com/en/app-notes/index.mvp/id/5527

BTW same applies to various magnetic materials, like ferrite or various powdered iron mixes. If you want to build high-dynamic range filter/preselector you have to use big cores (or use no core at all). Surely the receiver must be balanced, there is no need to have super-filters if mixer/IF/LO are not to par.

>>1336085
Yeah, it's a MFJ-2010 and a Yaesu FC-707

>>1335994
>Also share your thought on dipole-like multi-band antennas, I'd like to have 80 m, 40 m & 20 m bands.
G5RV

7200 is INSANE today, I mean A LOT more than usual, there's a bunch of new people riling Dan K9RSY up more than usual. I think he's about to have a heart attack.

>>1336109
>3MHz high-pass followed
Shit, couldn't I go with 300kHz or something instead? I'd like to not cut out half of the SW bands and all of AM radio if possible, and hearing up to 26MHz would also be a small bonus. I hear the mini whip is particularly good at avoiding low-frequency noise. I've got a component tester to check the inductance of hand-wound coils, though I'm unsure how well it will work for coils in the nH range.

>>1336407
>coils in the nH range
filter of the day

>>1336432
Looks like I'll need to learn how to do an FFT with spice, or otherwise learn to use algebra to analyse LCR networks as a function of angular frequency.

>>1336435
instead of plotting v() try vp() and vm()

>>1336435
man .ac

>>1336451

>>1336407
>Shit, couldn't I go with 300kHz or something instead? I'd like to not cut out half of the SW bands and all of AM radio if possible, and hearing up to 26MHz would also be a small bonus. I hear the mini whip is particularly good at avoiding low-frequency noise

You can go with whatever you want mate. If you want to get something more-or-less decent and have higher chances of receiving DX stations you have to eliminate as much noise as possible. You see most of the man-made noise / atmospheric noise gravitates towards low frequency. Allowing all that shit into the up converter places very high demand on IMD, BDR and IP3 performance for both the up converter and the receiver. Otherwise DX stations will be masked and drown in noise.

>>1336407
>I hear the mini whip is particularly good at avoiding low-frequency noise.
It works fine in quiet rural installations, if mounted high enough and with good ground plane under it.
If you try to use miniwhip in noisy city environment you are likely fucked. Like proper fucked.

You should go with active loop antenna instead as it's naturally not susceptible to
E-field noise pick up in near field.
https://en.wikipedia.org/wiki/Near_and_far_field
https://en.wikipedia.org/wiki/Loop_antenna
10-20M random wire + 1:9 unun would be good as well.

>>1336453
You wont get anything close to that in real life due to limitations of thee capacitors (ESR & ESL).

>>1336460
>10-20M random wire + 1:9 unun would be good as well.
P.S. I had better luck with random wire from my windows to the nearest tree than with active antennas.

>>1336460
The pic has "S-unit" scale on the right. You can see that you'll get S9+ noise every fucking where lower than 1-2MHz.

>>1336460
Sounds like the complete opposite of what I read here:
http://dl1dbc.net/SAQ/Mwhip/Article_pa0rdt-Mini-Whip_English.pdf

>>1336484
>http://dl1dbc.net/SAQ/Mwhip/Article_pa0rdt-Mini-Whip_English.pdf
I'm not going to argue what that .pdf, you can believe whatever your want, just finish the project and test it. It's fairly small and you will be able to test it in & out of your city.
Also browse sdr.hu and compare SDR's with different antennas, more specifically miniwhips and loops. Then check how many hams or navy/military guys use loop antennas and super-small receiving antennas something akin to "miniwhip".

>>1336503
The main reason I'm opting for this is because I don't really have anywhere suitable to mount a large antenna, not to mention I'm moving around a bit. Not to mention it seems to be much better at picking up a wide array of frequencies.

The pdf seemed to push its main point as being that the mini-whip receives the electric field of the RF as opposed to the magnetic field, and that much of the noise you'd get in the electric-field would be blocked by walls and such, meaning that you wouldn't get any interference from wires in your house acting as antennae and such.

There's about double the loops compared to mini-whips. Either way I'll build one and see.

>>1336562
>The main reason I'm opting for this is because I don't really have anywhere suitable to mount a large antenna, not to mention I'm moving around a bit. Not to mention it seems to be much better at picking up a wide array of frequencies.
My experience:
Just a loop of 3-5 meters of cable in a window frame connected to a balun performs a lot better than a miniwhip located indoors or near the window.
Active wideband loop antenna (there are two designs worth to mention: Levkov's preamp and Trask's preamp, adding a 1-to-1 transformer similar to the one used in Trask's amp reduces rf noise; Trask's preamp is the best).
A sloper / random wire from your window/balcony to the nearest pole/tree, with a length of at least 10-15M and at least 4-6M over the ground is much better than active loops.
A dipole /city windom,/ OCFD / G4RV are much better than a random wire antenna.

>>1336679
I don't plan on locating the mini whip inside, but rather to stick it out my window by a few metres on a bit of PVC or dowel. I know one of its shortcomings is that the electric fields that it picks up are blocked by walls, as opposed to a magnetic antenna like a loop.

>>1336460
>that image
Is that really how much noise there usually is? It seems the noise levels listed for the VOACAP propagation prediction site are way massively optimistic (with the worst possibility "noisy" being -139 dBW or -109 dBm, which is where "rural" sits on that chart at 7 MHz). That really explains why people kept telling me starting with running low power is a bad idea.

>>1336686
>with the worst possibility "noisy" being -139 dBW or -109 dBm, which is where "rural" sits on that chart at 7 MHz
Oops, "rural" sits at about -100 dBm on that chart not -109 dBm. For some reason I was looking at 12 MHz when I made that post. VOACAP's "rural" background noise setting is -150 dBw or -120 dBm though, so it's a good 20 dB off what that chart shows (same with the "residential" setting for VOACAP) and the 40 meter 5 watt QRP propagation predictions I was looking at and wondering why people thought I wouldn't be satisfied with would actually need 500 watts to achieve that level of performance.

>>1336685
>y a few metres on a bit of PVC or dowel
If "a few meters" is more than 2.5-3 meters? I would be kind of hard to do that.

>>1336686
>Is that really how much noise there usually is?
Man-made noise gets worse and worse as time passes by. At my location it's much-much-much worse than that. I have railroad freight train station within 2 miles, one medium sized electrical substation and another pretty-big one near the train station.

>>1336707
>I wouldn't be satisfied with would actually need 500 watts to achieve that level of performance.
I usually can copy guys running like 1kW+ and with full-sized / multi-element antennas. CW is more efficient than SSB but I haven't mastered it yet. :\
Anyways there are a lot of people like me living in noisy areas, I'm going to build a 1-1.5 kW linear amp this year to give them a chance.

>>1336712
>would be kind of hard to do that
Maybe a fishing rod?

>>1336713
>CW is more efficient than SSB but I haven't mastered it yet.
I know that, I was actually looking at CW from the beginning since CW at 5 watts is comparable to SSB at 100 watts. It still kind of sucks finding out that the 100 watt SSB transceiver would be represented by a 1 watt SSB transceiver in that simulation and that I'd have to pay significantly more and settle for something not portable to get the level of performance I was seeing.

>>1336729
>100 watt SSB transceiver would be represented by a 1 watt SSB transceiv
Huh?

>>1336721
>Maybe a fishing rod?
I saw few guys on various forums who use long fishing rods just fine on 40 m and higher bands (such antennas would work nice for RX on 80M I believe). It still requires solid hardware to support its weight.

https://www.qrz.com/db/VR2VAZ

>>1336721
They call them squid poles in vk. Lots use them for portable use.

>>1336721
>a fishing rod?

We call these big ones squid poles in VK. Lot use them for portable use. The are telescopic. I'm aware of up to 15 metre long ones.

>>1336769

>>1336772

>>1336773

>>1336737
>Huh?
Using the VOACAP propagation predictor with transmitter set as using SSB at 1 watt is the level of performance I would actually be able to expect from CW at 5 watt using their extremely optimistic noise floor. Pic related is a screencap showing both the predicted coverage areas with CW at 5 watts with their extremely optimistic noise floor and with the average 7 MHz noise floor from the chart posted here: >>1336460.

>>1336686
>>1336707
>>1336729
>>1336926
You're as bad as the idiots in /g/ that are constantly posting computer specs. There are so many variables, predicting the weather accurately is about equal in difficultly.
LARPing is all you really want to do though, so watch some more weebo shit and continue to post your "in depth analyses" about something you have no hands-on experience with.

>>1336964
VOACAP doesn't give detailed predictions. It just gives a percent likelihood of one station being copyable by another given a certain month, hour of the day, and solar conditions. You compare it to weather prediction, but weather predictions are significantly more granular than "there's a 5% chance of having snow on any given day this month, we have no clue what days it'll actually happen".

>>1336981
Chance in weather means that given the current conditions, historically, the same conditions have yielded precip. (or conditions) 5% of the time. Also, propagation is dependent upon space weather, therefore they are extremely similar.

I have a yeasu vx-6, any interesting stuff I can do with that?

I haven't done any radio projects before but I have a little experience in electronics.
I want to make a transmitter and receiver to send just one bit of information, a simple on-off, a distance of 100 yards over open land. I want to be able to tell the difference between "off" and lost signal, so I want to use amplitude modulation with some tone, where tone or no-tone would correspond to a 1 or 0 output, while a loss of carrier could be detected and handled.

There are a ton of little tutorials out there about simple AM transmitters but I haven't found any that go in-depth about how and why those circuits work. And I want it to work in the real world, reliably, without causing harmful interference. Any suggestions on what I should read to get started?

the transmitter is handheld, it'll be in a metal box which will be the ground reference. I was thinking I'd use 72MHz or a similar band meant for hobby and RC which doesn't require a license.

I'd be open to using some off-the-shelf modules but I'm not sure what's available that would fit my needs.

>>1337009
Ages ago I made such a thing running at 40.68 MHz. I used DTMF chips, HT12 if I remember right, probably obsolete now. Today I would use 433 MHz modules.

>>1337062

>>1337190
is this in dunecoon land?

>>1337009
i know someone who is doing something like that, ill have to ask him, hes using it to turn on/off an electric fence. if you have knowledge of electronics, i would jsut get you ham license, and youll be able to operate on a wider band of frequencies. might make some friends as well.
ill give him a ring tomorrow and see if i can get some info on it

>>1337202
i would jsut
i would suggest
my god how did i fuck that up so bad

>>1337009
I think 433MHz is the place for you, anon. the ISM band is usable without a license. modules are dirt cheap and available for like a buck. antennas can be relatively small
you can use the HT12D/HT12E (which are not DTMF, but a binary pulse modulation code) with those modules to encode from button inputs on one end to a bitstream, transmitted and received by the radios, then decoded to logic level outputs. they're fairly robust against unintended operation by noise due to the 8-bit address and they are easy to design with. some vendors even sell pre-made key-fob type remotes with these chips, but you might want something a bit more powerful. you'd just need a little logic on the receiving end to latch the state of the switch, like a flip-flop, and whatever to turn your sexytime hot tub on and off

>>1337009
>There are a ton of little tutorials out there about simple AM transmitters but I haven't found any that go in-depth about how and why those circuits work
Tutorials aren't meant to go in-depth and provide exhaustive information on components being used.
If you are after a simple device to remotely control something then just get chinese 315/433/868mhz chinese RF modules (it depends on your region).
If you are to know how RF stuff works you have to get read quite a few books if you really do want to know how stuff works "in-depth" (that includes books on antennas, RF propagation, books on semiconductors, transmitters, receivers, etc etc etc).

>>1337223
>the ISM band is usable without a license

Not in my country. That said if you are a human within the country you have one via a class license automatically.

>>1337009
Depending on your application you might look into IR which is license free and safe from problems with harmonics.

>>1337456
>Not in my country.
There are many ISM bands in every country which are free to use
There is also a CB band (27MHz), most old Chinese RC toys use it
2.4GHz is allowed everywhere and there are plenty of RF modules for that band.

>>1337494
The point was that wile its free it is actually licensed so that it can be revoked if the govenment felt like it.

Here some of the ism bands are shared with amateur use however amaterures are allowed to use much greater power on them.

>>1337577
May I ask you what country is it?

>>1337223
These little 433MHz modules are just what I need, I think. Cheap, too. $10 for a six pack. on-off keying or amplitude-shift keying, I can put any data I want through it. Thanks.

>>1337648
no problem m8
just remember that they have a binary output but don't have a separate carrier detect output, so you need to defend against unintended operation from noise etc. via AFSK ("off" tone and "on" tone) or PWM or whatever

>>1337664
I was thinking my enable signal would be a simple square wave heartbeat signal with like a 50% or less duty. In the receiver I'd have a one-shot triggered on the falling edge of it, its output would be normally high, goes low for a brief period when triggered. The rising edge of the one-shot is the clock input to a D flip flop which samples the heartbeat signal. it'll sample a 0 when enabled.
to disable, the transmitter would increase the duty cycle so the D flip flop would sample a 1.
The one-shot's output also triggers a transistor to top off a capacitor which discharges slowly. If the signal is lost, the capacitor runs down over a few seconds and disables when it gets too low. that'll give a few seconds for the signal to come back before anything happens.
if it receives interference which causes the output to be high all the time, same thing, the capacitor runs down and disables after a few seconds.
testing will tell how well this works and how reliable it is at a distance.

https://en.wikipedia.org/wiki/ISM_band#Frequency_allocation

>>1337743
a few points:
those receivers are pretty broadband, and will pick up basically anything on 433.x MHz
Part 15 devices aren't supposed to use ISM remote control bands for continuous transmission. better to send only on state change
consider the types of noise you will receive on this band. those Holtek chips use PWM, heavily encoded, and are not uncommon in RF remotes. automotive remote keyless entry systems, among others, often use 433MHz. should at least check that your rising-edge to rising-edge times are within a fairly tight band before storing the result, and maybe should use a serial-in-parallel-out shift register to help make sure it's your signal
also, I'd probably avoid critical R-C time constants on either end if in an outdoor or unconditioned environment. I'd probably avoid analog processing altogether if life and/or property were threatened by whatever's on the receiving end

First time posting here. This thread seemed like the appropriate place to ask about this. If not, let me know and I'll start a new thread.

I was planning on building this using materials I have on hand. I have 24 and 26 gauge enameled wire, and several different diameters of PVC. (Also have the remaining parts.)

The author didn't note the inductance values of L1 and L2. To make matters a bit worse, the author notes the PVC actual diameter is 3.25", but the one I have is 3.5"

Using the formula below:
L= (a*a*N*N) / [(18*a)+(40*l)]
where
L= Inductance in microHenries
a= Coil diameter in inches (PVC diameter plus wire diameter)
N= Number of turns
l= Overall length of the coil in inches

Using 22 gauge wire (.0267") and assuming he did use 3.25" diameter PVC, I calculate L1 as 203uH and L2 as 143uH.

Not sure how to determine inductance value at the center taps. Also, I'm not sure what formula defines the space between L1 and L2.

My goal is to use 3.5" PVC and 24 gauge (0.0213") or 26 gauge (0.017") wire. Any input would be appreciated....

My first time "Posting" here as well I swear.
Enjoying the priceless information and comradery. So relaxing reading and stamping.

Peruvian station calling CQ on 1902 for anyone looking for a rare DX

>>1337857
>Not sure how to determine inductance value at the center taps.
what for?

>Also, I'm not sure what formula defines the space between L1 and L2.
Distance between these coils defines amount of inductive coupling between these coils.
Don't overthink things, just built it and enjoy. It's not a rocket ship there is no need to be anal about every single thing.

>>1337916
True, never are space craft designers, they made their exteriors out of bloody foil for hilarities sake

>>1337916
Well is my second attempt at making a radio. My first one was based on a simpler circuit. Unfortunately, there is an AM transmitter about 2 miles away and its drowning out all the other stations. Turning the cap only lowers that one station's volume.

I have enough wire for two more coils. If my second attempt doesn't work, I'm probably just going to drop this project.

BTW - I was pretty happy with my first coil. I did the math above for a 250uH coil and it measured 252uH.

>>1337958
I had active AM transmitter within 5 miles while I was in school, built few crystal radios and all of them were working just fine & audio volume was impressive

what kind of antenna and ground are you using?

>>1337958
>Turning the cap only lowers that one station's volume.
No peaking?

>>1337974

This image was for my first build, using a 250uH coil and a 0-365pf variable cap.

>>1337971
Referring to my 1st attempt using a simpler circuit. I pulled apart an old spool of telephone line and ran a wire from my 2nd floor bedroom to the backyard fence. (about 60 ft.) Didn't have a ceramic insulator, so I capped the fence end with some hot glue. Using the screw on an electrical outlet as a ground.
I could try an earth ground, but all I have is a tent peg or could try a metal coat hanger. I'm the NW US, so the dirt is usually damp most of the year.

>>1337974
Referring to my first build. Not sure what you mean by peaking. There is no "sweet spot" when turning the cap. If I remember correctly, the one station was loudest when the cap plates were fully unmeshed and lost volume as I turned it.

I used to have a few radio shack kits when I was younger. Those crystal radio projects used a ferrite based coil, and picked up stations 20 miles away with only a 10 foot wire antenna.

>>1337995
Connecting antenna like that kills selectivity, adding just one capacitor would help.

> wire from my 2nd floor bedroom to the backyard fence. (about 60 ft.
More than enough.

>Using the screw on an electrical outlet as a ground.
Is it grounded?

>. There is no "sweet spot" when turning the cap. If I remember correctly, the one station was loudest when the cap plates were fully unmeshed and lost volume as I turned it.
Inductance was too high. Removing 1/2 of turns should've helped.

>>1337999
I don't have any small trimmers, so I'll try out different caps on the antenna line.

I'm assuming the outlet screw is grounded. Will try to setup an earth ground tomorrow.

I'm hesitant to pull apart my first coil, as I took a lot of care in winding it. I think I'll start a new coil and test the performance every ten turns or so.

>>1337857
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/indsol.html
Use SI units and save yourself the headache.

>>1338005
Add a large-ish capacitor in series with the trimmer, the resultant capacitance will be C1*C2/(C1+C2); somewhat smaller. But changing the coil is preferable.

>>1338005
>I'm hesitant to pull apart my first coil, as I took a lot of care in winding it. I think I'll start a new coil and test the performance every ten turns or so.
You don't need to. I was referring to your previous set up. Complete whatever you started and work from there. There must be "a sweet spot" so the volume of the station is at its maximum. If there is no such spot then the LC circuit is way off.

>>1338005
>I don't have any small trimmers, so I'll try out different caps on the antenna line.
Any capacitor in that range would work.


Again it's not really needed if you use inductive antenna coupling, but you'll improve selectivity if you replace it with another variable capacitor (15-500pF) in series with the antenna coil. Varying distance between the coils also helps.

Oh and don't forget that you need to use high-Z headphones, generic 16-33 ohm earbuds aren't suitable, unless you use AF transformer to do impedance match.

Has anyone connected a SDR dongle to their Chinese car stereo with Android opering system using car antenna for a all band scanner. I use hdsdr now and see there is a app for Android 6.0 that comes with the car stereo. I am going to get a extended antenna to around the 2 meter band length. I want to listen to p25 and Motorola didgital also but don't see anyone doing this with the Android operating system app. Is this a thing people are doing?

>>1338338
It's certainly possible, but watch what SDR dongle you have, it may not necessarily be compatible with the app.

>>1338381

>>1337999
If anyone is still observing this conversation, I hammered a 3ft earth ground and tried 10, 20, then 30 pF on the antenna. I can now pick up 4 distinct stations as I adjust the tuner.

I hope to build the radio below next weekend.
>>1337857

>>1338465
Glad it helped.

>>1338338
Results of your "idea." (pic related)

has anyone here homebrewed a vertical? wanting to build one, but kinda confused by the coil and matching system. if anyone has done this before or can point me in the right direction id appreciate it

>>1338519
what band(s)

>>1338521
i would try to get as many HF bands as i could.
160 would be tough because of size, but for right now im just looking to experiment

>>1338522
Any limitations on max height/weight/etc?

>>1338522
What materials are available?
Just be real, you can't have one antenna for all HF bands. What are the most important bands for you?

Where are you going to install the antenna?

>>1338658
just money at this point, im on about acre of land.
>>1338757
i have a bunch of metal poles of different sizes, couple hundred feet of 12ga stranded wire, some solid copper wire in some romex. lots of other stuff as well, ive just been collecting anything that might come in handy for building. i have a 30 ft tower that i havent put up yet, and a 30ft telescoping pole.
i know i cant have an all band vertical, but i really enjoy 80/40/20, but also enjoy shortwave listening.(below 160) but for now i would liike to focus on the ham bands.
i can install it pretty much anywhere on the property, where it will fit

>>1338870
if you have land and you only want to listen (for now), a Beverage antenna is good

>>1338870
Well you can install multiple antennae.

How in the hammer hell did this thread make it back up?
73's and 88's Stampies

I bought a rtl sdr and an rg8x cable. What connector do I need to mate the two? The connector on the rtl is really small

>>1339059
for mine it was the one in the middle of the picture. i think they come with different ones but that one is really small and probably what you need.
>>1338970
i thought they were really long wires? you having a laugh m8?
>>1339053
thats probably what ill end up doing. the coils on the bottom of the verticals is what is confusing me.

I can get enamelled copper wire cheaply, are these usable for long antennas?

>>1339083
What gauge?

>>1339083
Braided wire is better for any run longer than a few meters, Solid wire tends to weaken in the wind and snap.

>>1339063
>you having a laugh m8?
yeah nah you cunt :^)
the point stands, the REAL Beverage antenna is great for receiving, if you have the space, don't have the altitude, and want directionality. otherwise it's froot loops for yoo

>>1339089
ha
what i was planing was using about 700ft of wire in a large loop. this would be for shortwave listening. dont think id get it to load on the ham bands. would be neat if it did.
so beverage antennas should be straight? i didnt know. thanks for that m8. i have 1000s of feet of wire, whenever i pull someones well out i just keep the wire. most of its solid copper, but good for at least testing something out, and i dont really care if it breaks or gets messed up, its free!

>>1339132
yes, straight
>1000s of feet of wire
get some non-conductive fence posts or similar, a core to wind a matching transformer, and you're all set. you probably have plenty of wire left to eventually build a separate loop or quad for tx, given poles

>>1339132
>shortwave listening
>dont think id get it to load on the ham bands

Most of the ham bands are in the HF frequencies (shortwave).

>>1339140
>most
That's quite the generalisation. It's a little less than half, but the common 2m isn't there, and all the sub-1m

>>1339268
by band allocations, HF wins
by bandwidth * popularity, UHF wins

>>1339084
0.3 mm

I have to admit
The only intelligent thread on /diy/
kill me lord

>>1339350
Too thin but would work nicely for a temporary RX antenna for HF/SW.

>>1339294
by distance HF wins hands down

>>1338519
>, but kinda confused by the coil and matching system. i
Do you have a decent LCR meter?
Antenna analyzer / network analyzer / spectrum analyzer with a tracking generator and a directional coupler?

>>1339371
What dimensions do you recommend?

I see I can get some silvered copper wire too, does that make much of a difference?

Who is the /pol/tard talking on 7200 right now?

>>1339059
>I bought a rtl sdr and an rg8x cable. What connector do I need to mate the two? The connector on the rtl is really small
It's MCX
You need a pig-tail, like MCX-BNC or MCX-SO239 or MXC-TypeN and BNC/SO239/TypeN connector for you RG8X.
I also bought 24' of RG8X cable, going to install a OCFD dipole for 40/20 meters, will test with RTL-SDR + home brewed up converter. I put type-N connectors on the coax. To make my life easier I replaced MCX connector with SMA, the footprints of the connectors are absolutely identical (so you need just a soldering iron and a 90degrees SMA connector), however MCX is 75 Ohm but SMA is 50 Ohm, not that it really matters for the receiver.

>>1339952
Don't the new ones use an SMA connector instead of an MCX connector?

>>1339956
>Don't the new ones use an SMA connector instead of an MCX connector?
Only with built-in upconverter or a direct-sampling mod. Generic RTL-SDR TV-tuners come with MCX connector and it's packaged in tiny plastic case.

>>1339460
>What dimensions do you recommend?
I have book from early 60s, there is a table on wire antennas:

Distance between poles / wire Length:, solid center conductor wire diameter / multi-stranded wire (all wires are uninsulated)
25 m / 26 m: bronze: 1.0mm, copper: 1.6mm; bronze 0.35mm x7, copper 0.5 x7

40m / 41m: bronze 1.5mm, copper 2.1mm; bronze 0.5mm x7, copper 0.67mm x7

50m / 52m: bronze 2.1mm, copper 2.6mm; bronze 0.67mm x7, copper 0.52mm x19

60m / 62m: bronze 2.1mm, copper 3.0mm; 0.67m x7, bronze 1.0m x7

70m / 72m: bronze 2.6mm, copper 3.0mm; bronze 0.67mm x7, copper 1.0mm x7

80m / 82m: bronze 2.6mm, copper 3.2mm; bronze 0.52mm x19, copper 0.64 mm x19

Aluminium wire must have cross section area 3 times bigger than that of bronze wire.

>>1339460
>I see I can get some silvered copper wire too, does that make much of a difference?
nope, no difference at all.

>>1339968

Tried Google, got no luck.

Can you fold a G5RV? A full G5RV will come too close to metal (within 8 feet) on my property no matter how I place it. If I could fold it, I could keep far away from metal.

>>1340017
Post a sketch, it's hard to understand what are you talking about.

>>1339961
>Only with built-in upconverter or a direct-sampling mod
Why get anything else these days when you can get one with direct sampling and a metal case for EM shielding for $20? Is getting one without those features and with a less common antenna connector really worth it just to save a few bucks?

New here. What is a relatively easy to build antenna if I want to listen to anything I can receive with directsampling sdr?

>>1340022
Green= tree
Red = metal
Blue= a folded G5RV, like a folded Dipole.

Will it work?

>>1333432
just creamed in my shorts.

>>1340023
>Why get anything else these days when you can get one with direct sampling and a metal case for EM shielding for $20? Is getting one without those features and with a less common antenna connector really worth it just to save a few bucks?
I bought mine a while ago, like 4 years ago.
I don't recommend direct-sampling, you'll end up with lower sensitivity and selectivity. I managed to copy hams ca. 8000km away with DIY bandpass filters & upconverter & random wire antenna. You absolutely can't beat that with direct sampling. And that's in extremely noisy environment.

>>1340032
Is the sketch to scale? I.e. are you going to fold it like twice?

>>1340047
I'm going to fold each radial like a folded dipole.

Hey guys!
Not sure if I'm in the right place but let's see.
I want to stream an online radio stream from this website http://www.listenlive.eu/index.html around my house so I could listen it on my FM radio whenever I want to.
I'm planning to stream an FM signal through my raspberry pi 3's GIPO antenna.
I can already stream .wav files and "catch" them with my radio, but I'm not sure how to stream the online radio stream.
Could somebody tell me where should I start or what should I do?
I hope I explained it well.

>>1340049
in half?

>>1340055
It's not a "GIPO" it's GPIO.
What you've done is just built a wide-band frequency modulated noise source. There are no filters nothing! that filters PWM.
Go to ebay / frys wherever and get "mini FM transmitter" or "fm modulator" instead.
Thanks to faggots like you 80/160 and lower frequency bands are full of noise and barely usable in urban areas. Go away, I personally will not provide you have any help with this atrocity unless you get / build a real fm transmitter and a post a picture of it.

>>1340067
Will do so then, thanks man!

>>1340067
Not him, but can you build a D-class fm transmitter and run it off the PWM pins off an Rpi? Probably better to generate the audio frequency and the carrier frequency separately though.

>>1340079
>Not him, but can you build a D-class fm transmitter and run it off the PWM pins off an Rpi?
Generally there are class-D amplifiers for HF, class-E and class-F amplifiers for VHF/UHF, but they require decent filters and designing/building/aligning them is way beyond most anons knowledge.
> Probably better to generate the audio frequency and the carrier frequency separately though
What is frequency modulation (FM)? How are you going to implement it if you follow your suggestion?

>>1340088
I think you may be able to use a mixer to modulate the frequency, provided you use the correct intermediate signal. You know, sin((2πf_1+2πf_2)t) and all that. But usually I guess you'd have the oscillator itself modulate based off the audio signal fed into it. I haven't looked it up as you may be able to tell.

>>1339952
>type N connectors
y tho

>>1340099
>haven't looked it up
you should probably do that instead of shitposting

>>1340112
For RG8X I had basically two options: SO239 or TypeN. That's what's available in the nearest store which is literally 1 mile from my home.
I went with TypeN connectors because
- I don't have any ham gear which comes with SO239 connectors
- I already accumulated lots of various adapters/pigtails and such and neither of them come with SO239.
- they are superior to SO239

>>1340099
>I think you may be able to use a mixer to modulate the frequency, provided you use the correct intermediate signal.
Mixing audio + carrier will give you DSB signal. Basically it's AM with eliminated carrier. If you filter one of DSB signal side band you'll get SSB signal. It's not what you want. You need FM signal
For FM you need to module FREQUENCY, and frequency deviation for WFM is +-50...+-70 kHz.

>>1339968
FAQ dude here. Your table looks interesting but is not entirely clear. Why is the wire length 1 - 2 m longer than distance between poles? Also what is meant by "0.5 x7"?

>>1334481
you can use MAT, icon is like a chicken with a mallet, drop files in, clean then check - all meta data gone!

>>1334521
how constructive, sounds like you don't know shit and instead of helping felt the need to comment without contributing.

sudo apt install mat

>>1340173
An FM signal is in the form A*cos((w_1+cos(w_2*t)*t).
cos(a)*cos(b) = cos(a+b)/2+cos(a-b)/2, and this is what a mixer does.
Therefore, if a = carrier frequency = w_1 and b = cos(w_2*t) then you get an FM signal out, with the right filtering. This does mean that your intermediate signal must be cos(cos(w_2*t)*t). Unfortunately, cos(cos(wt)t) has a frequency that somehow keeps increasing as a function of time, meaning it is not possible to produce.

>>1340267
>1-2m longer
droop, mechanical termination, etc
>x7
strands, probably

>>1340170
ah, fair enough, given the choices

>>1339063
Not an mcx. Wish I had a radio shack near me

>>1340348
Audio signal isn't a single tone signal, you assumptions are absolutely wrong (for dummies: you can't mix audio + carrier and get FM signal)

>>1340389
>Not an mcx. Wish I had a radio shack near me
Mate you were given a pic with connectors and their names
>>1339063
You got SMA

>>1340389
>he bought a new model RTL-SDR
>he can't even bother to look at the product description for the item he purchased where it says what kind of connector it uses
Furthermore, if you couldn't get that information from the product description, why did you wait until now to post a picture instead of expecting us to know exactly what you were talking about?

Why are there so many fucktards on this site these days?

>>1340389
Good luck with the V3.0. Virtually useless for me even with an AM Band Pass filter, I still get harmonics from an AM station about a mile from me.

>>1339413
i have an antenna analyzer
>>1340331
>>1340333
thanks fellas

>>1340404
>Why are there so many fucktards on this site these days?
>these days
>reddit spacing

>>1340410
>AM Band Pass
kekekek
srsly tho, I guess you'll have to notch out their harmonic spurs too

>>1340463
I'm saving my pennies for an SDR Play. It was meant to be a panadapter for my TS-590SG but it feels like I'm putting E85 in a Corvette, so I'm upgrading.

>>1340410
How are you using it, normaly or via direct sampling? How many watts is the AM station broadcasting at?

>>1340474
Direct sampling so I can use it for HF. The Radio Station's tower is 10,000 watts and located 0.73 miles from my house according to Goggle Earth Pro. They're bleeding because my Kenwood picks them up in the 80, 40, 20 meter bands as does my Hellicrafter's S-85 on the same frequencies.

I filed a complaint (as did several other hams in the are) to the FCC but we're not holding our breath. As long as they're not fucking up commercial signals, the FCC isn't gonna do shit.

>>1340396
I never said audio*carrier, but carrier*intermediate.
>I think you may be able to use a mixer to modulate the frequency, provided you use the correct intermediate signal.
Turns out that intermediate signal is impossible to make though, and the other signal (cos(a-b)/2) is problematic. But the assumption that you can replace any single sine with an audio signal is completely correct; b could be Acos(w_a*t)+Bcos(w_b*t)+etc. and the result would sill be an FM signal. I would have put a sum in there if we had TeX here.

Probably a dumb question and I don't know where to start a search for the info but can you use an SDR and some sort of specific software to monitor Michigan's Public Safety Communications System (MPSCS)?

I know "Project 25 Phase I" means something about the trunking and encryption, just not sure about anything beyond that.

My city switched over to MPSCS a few weeks ago from VHF and I miss listening to the police band.

>>1340504
http://osmocom.org/projects/op25/wiki

>>1340513
Kiitos.

>>1340504
DSD for SDRSharp will do P25, DMR, DSTAR... few others.

P25 generally isn't encrypted - it's digital. Encryption is available, but it's costly (hardware, key management, battery life) and generally isn't used unless necessary.

I have a few keys in my radio for testing the system but almost never use it.

>>1340475
I'd be looking at a second antenna and do some phase cancelling on the offending signal.

At that proximity and power combined with using gear which is only ham grade interference is more or less a given.

Anybody know a good VHF mobile where the front end doesn't get overloaded so damn easily?

Preferably has VOX for data modes.

200 or more channels.

?

Any with Fusion or DMR in addition to those?

>>1340519
:DD

>>1340526
fucking emcomm buyfags have ruined everything good about ham radio
the code requirement was clearly not enough, sons of bitches need to be forced to build their own QRP rig from components on the spot

>>1340498
Using a mixer you can surely get frequency modulated signal if you already have frequency modulated signal. As all a mixer does is just frequency translation.
It's impossible to "modulate the frequency" (citing you here) with a mixer, it's only possible to translate it.

>>1340524
>At that proximity and power combined with using gear which is only ham grade interference is more or less a given.
There is ham gear designed / suitable for field-day contests where there are lots of transmitters extremely close. There are also DIY designs which would cope with OP's conditions relatively easily. Even from 80's era.
Most of it's costly AF and often big and heavy.

>>1340380
>>1340380
>droop, mechanical termination, etc
yep
>>x7
>strands, probably
yep

>>1340457
>i have an antenna analyzer
Well then you can try to build some simple trapped vertical, there are plenty of design available.

>>1340546
That's true.

Stupid question: cable loss is specified in dB/length. Do they really imply that loss increases exponentially with length? That, at 450MHz, a 10m length of RG-58, with a specified loss of 34.8dB/100m, will only cost me 3.48dB, not 24.8dB?

>>1340647
Not sure I got your question.
Cable loss expressed in dB/m is what it is, a loss in dB per meter, that's 34.8 dB / 100 m = 0.348 dB / 1 m = 3.48 dB / 10 m = ca. 70 dB / 200 m = 7 dB / 20 m = 0.7 dB / 2 m

>>1340647
>loss increases exponentially with length
It is easier to see this as an exponential decay. The first 1 m takes 10 % leaving 90 %, the next 1 m takes another 10 % but that is 10 % of the remaining 90 % from the first 1 m stretch. So net remains is 81 % (0.9 x 0.9).

>>1340647
>will only cost me 3.48dB
yes, after 10m more than half of the power is gone

>>1340659
Can confirm having stuck a power meter on the end to measure loss at 477mhz.

>>1340676
rg213 or rg8 is what I'd use for 10m at 23cm

Please share your experience with antenna-modelling software.
So far I've tried MMANA and it looks kind of odd as there is no easy way to enter antenna elements, you have to punch shit load of numbers.

>>1340475
The ham police will do nothing there a church near me running around 500 wats on their low power licence on FM but their set up sucks and splatters the band for about 2 blocks. So here we have illegal power over limit and band interference for around 6 years now. I get a good laugh when ham fags say they are going to shut you down for calling them gay on their hands. Just listen to the .435 to see how hams talk to each other.

>>1340727
Or 7.200 or 14.313

>>1340774
7.200is already is already starting. how do these losers have nothing better to do?
im beginning to think i can do whatever i want on the radio and never get in trouble. these guys have been doing this for years. if someone wanted to find them, they could, but they dont.

>>1340776
Laura Smith sent K9RSY and K1LEM several warning letters! Fear her!

>>1340779
yeah, but it seems like unless you mess with the emergency services, nothing really happens. i just wouldnt do anything like that because i wouldnt want my closer fellow hams to hear me, and i dont see the point. i got off cb for a reason

>>1340780
Yeah, I don't have an antenna for 160 meters but I really want to build one because that seems to be the only band not infested with shitheads. I avoid two local repeaters because of the infighting that goes on on them.

>>1340785
yeah, im putting up dipole for 160, i just have to fire up the other end into a tree. plus as a general i get the whole band. my club repeater has no infighting, and thats great. but i hear people arguing on some of the others, and some jamming. someone got on ours a few weeks ago and was just saying all types of rude shit, so we put up some RDF antennas to help find him, should he strike again. he was on an HT, because we could all easily talk right over him

>>1340787
One guy at my club as a pseudo-Doppler RDF made from a Pi and an SDR. As long as he's moving, he can triangulate a signal in under a minute. We also have club members who are cops who are glad to knock on the doors of these kids with their Baofengs and scare them off from QRMing.

>>1340791
thats pretty awesome. do you have anymore info on the RDF with the pi? i know people would love to put that together

>>1340795
Afraid not. The guy wants to build and sell his design to compete with the MFJ one for about $100 so he's keeping the design and software proprietary.

>>1340776
Is this an issue with voice only where CW is free from junk?

>>1340834
CW and PSK31 et al typically are free of QRM unlike phone. 7.200 and 14.313 are sort of "containment" boards like /b/. I rarely hear that shit outside of designated shitposting frequencies.

>>1340838
Phew!

I'll brush up on my Morse skills and get a little CW bug. QRP all the way and on the move. I see a few are fixed frequency at 7.023 MHz.

I wonder why they cannot be made the size of a cell phone. In fact there are many strange designs out there like the use of PIC processors and TI floating point DSPs. Just why!? A half way modern cell phone chip such as Snapdragon would be far better, faster, more versatile while using less power.

>>1340650
>>1340652
>>1340659
Ah, so. It is proper to use distributed element analysis rather than lumped in this case.
Thanks guys

>>1340848
I think it's mostly the filters and toroids that take up the most space. It is for the mcHF.

>>1340708
as opposed to what, exactly?
lern2geometry

>>1340848
if you don't mind mono-band operation, I'm sure they can
>A half way modern cell phone chip such as Snapdragon would be far better
>>>/g/

>>1340854
that's the trouble with the QSD for tx: mad spurs and the need for mad filters to clean them up
one might do better (for size) with an AD9851 or other proper DDS with quadrature sine outputs, AMed, mixed down, and amplified

>>1340848
>7.023 MHz

>>1340861
>if you don't mind mono-band operation, I'm sure they can
I wouldn't mind too much. the frequency might be OK for some DF tests I'd like to do.
>>A half way modern cell phone chip such as Snapdragon would be far better
>>>>/g/
I frequent /g/ too but find /diy/ more in depth.

>>>1340854
>that's the trouble with the QSD for tx: mad spurs and the need for mad filters to clean them up
>one might do better (for size) with an AD9851 or other proper DDS with quadrature sine outputs, AMed, mixed down, and amplified
Interesting. How about using one with a design like >>1340886 to get multi band operations?

>>1340924
fair enough, just be advised "moar is beddar" is a /g/ thing and not really a /diy/ thing. there's literally no advantage to paying extra for a Snapdragon chip (and the extra layers of a board it would require, power management, six gorillion decoupling caps, and so on) unless you really really need a GPU for 3D graphics flying around on your directional finding device. even then, it still won't synthesize actual RF signals for you, and barring that, a Pi is more than enough. remember, price and availability are paramount for homebrew
>the frequency might be OK for some DF tests I'd like to do
consider chinkshit AD9850s if all you need is CW tx on a fixed frequency. you won't need a whole lot of filtering to clean up
>Just why?!
I believe
>inb4 stop making shit up
PIC, Arduino, Pi, etc. are mostly the thing in ham due to the small overlap between digital and RF electronics. the large volume of literature and lore going back 20 years or more, with PIC's foray into ICSP, made it a no-brainer choice over the other main commodity option, which was an 80C51 with a full address/data bus and EPROMs. AVR was sadly a latecomer and somewhat under-represented, but STM32 seems to be picking up some speed these days thanks to, among other things, megasample DACs
>using one with a pixie
in the pixie, the crystal's role is cleverly switched back and forth between the inductive element in a Colpitts oscillator (for Tx) and a narrow band-pass input filter (for Rx). thus, a real crystal or other high-Q resonator is required. maybe you could usefully pull it to the next channel with a varactor and a voltage source, idk
>why they cannot be made the size of a cell phone
I think they could if old farts would get into the 21st century already and lern2SMT

>>1340861
>as opposed to what, exactly?
As opposed to any modern 3D CAD, like solidworks. I need first to model my house and then the antenna, punching all that shit manually is nonsense.

>>1337802
All good points. Seems like the HT12D/HT12E could be a good solution. I could send a heartbeat signal every second or two seconds.

Any considerations about antennas for handheld/mobile devices with no connection to earth ground?

>>1340967
>narrow band-pass input filter (for Rx)
No. It's a direct conversion receiver.

>>1341006
>I could send a heartbeat signal every second or two seconds.
permissible heartbeats under Part 15 on 433MHz are on the order of 15 minutes or an hour, iirc. if you are in an FCC jurisdiction, you should probably read the sections pertaining to the frequency range you want to use before you proceed
besides, the HT12x will provide significant protection against inadvertent operation by interference. you probably wouldn't need a heartbeat with those
on second thought, now that you've ordered the transmitters already... if you're really concerned about misoperation and don't mind smol microcontrollers in place of the HT12x chips, the nRF24L01+ would be great for this application. 1km range is not unusual with mods to the antenna. the 2.4GHz band is a wee bit more open to frequent transmissions under Part 15 and you have 125 channels to choose from. also the chips automatically handle checksumming and ARQ if the packet is corrupted so you wouldn't necessarily even need a heartbeat. all this, controlled by a convenient SPI interface

>>1341005
fug

>>1341005
do you really need to model your house? if you're putting the antenna on top, maybe analyze the house independently as a ground plane, or just guesstimate it, then plug it into the ground section of MMANA-GAL as such

>>1341044
The heartbeat isn't about interference, it's a fail-safe to disable the remote switch if the transmitter goes out of range.
How closely could these rules possibly be monitored? It's hard to believe sending a single code every two seconds could cause any mayhem.

>>1341044
>do you really need to model your house? if you're putting the antenna on top, maybe analyze the house independently as a ground plane, or just guesstimate it, then plug it into the ground section of MMANA-GAL as such
I want to evaluate verticals/ocfd dipoles/delta loops and slopers befre rigging anything.

>>1340780
Cb is actually very civil now band is wide open and noise is low during the day. our local channel has a net once a week. It's more fun to get on 2 meter and yell at those guys at this point. Now that everyone got a cheap Chinese handheld ham is destroyed.

(1/2)
>>1340967
>fair enough, just be advised "moar is beddar"
I am rather looking for a chip set for radio use. i know that Tentec uses Uno32, which while interesting is not quite that well suited.

> there's literally no advantage to paying extra for a Snapdragon chip
The Snapdragon is an ARM chip with a DSP, and it is meant for low power mobile RF use so it is a better fit than raspberry Pi or Arduino.
>(and the extra layers of a board it would require, power management, six gorillion decoupling caps, and so on)
I never noticed those on the boards I saw.
>unless you really really need a GPU for 3D graphics flying around on your directional finding device.
Nope, just CPU, DSP and some graphics. No 3d needed.
>even then, it still won't synthesize actual RF signals for you,
I had expected there would be some RF paths on the chip set. Data is hard to come by, do you have some?
>and barring that, a Pi is more than enough. remember, price and availability are paramount for homebrew
The Pi is a bit power hungry and not that well suited for DSP work.

>>1341202
(2/2)
>>the frequency might be OK for some DF tests I'd like to do
>consider chinkshit AD9850s if all you need is CW tx on a fixed frequency. you won't need a whole lot of filtering to clean up
Yes, I want to do CW and digital modes, not voice.
>>Just why?!
>I believe
>>inb4 stop making shit up
>PIC, Arduino, Pi, etc. are mostly the thing in ham due to the small overlap between digital and RF electronics. the large volume of literature and lore going back 20 years or more, with PIC's foray into ICSP, made it a no-brainer choice over the other main commodity option, which was an 80C51 with a full address/data bus and EPROMs. AVR was sadly a latecomer and somewhat under-represented, but STM32 seems to be picking up some speed these days thanks to, among other things, megasample DACs
Unfortunately these are also power hungry and not suitable for portable use. Qualcomm wants to engage the community, they say, yet they keep the prices unbelievably high and documentation close to inaccessible. Mobile phone chip sets are highly optimised for low power consumption while delivering good DSP power.
>>using one with a pixie
>in the pixie, the crystal's role is cleverly switched back and forth between the inductive element in a Colpitts oscillator (for Tx) and a narrow band-pass input filter (for Rx). thus, a real crystal or other high-Q resonator is required. maybe you could usefully pull it to the next channel with a varactor and a voltage source, idk
I had hoped a DSP could do the filtering, obviously need a ADC.
>>why they cannot be made the size of a cell phone
>I think they could if old farts would get into the 21st century already and lern2SMT
Elecraft KX3 has some SMT but not 100%. Discussions on the forum indicated many would hate touch screens but none commented on the alternative with buttons around the periphery as on the panadapter. So yes, I think many are too conservative.

Time for the 4chan rebel?

My dipole has stopped giving me 3:1 or better SWR on 40 Meters thanks to an ice storm/buildup. I can get 1:1 on 20 Meters, though.

Would transmitting on 20 with 100 watts heat the dipole enough to warm the wires and melt ice?

>>1340967
>I think they could if old farts would get into the 21st century already and lern2SMT
I thought the reasoning for this was due to the very limited selection of choices for finals on the hobby market that don't require 9V-12V or are only good up to 1-2 watts TX. It's kind of hard to make devices smaller when you still need to deal with bulky batteries to run them. If it wasn't for that, you could probably shrink a KX2/KX3 down to the size of a large smartphone (if you were willing to give up the physical buttons and replace them with a touch screen that is). On the other hand, you could just go with even lower power than the normal full 5 watt QRP (possibly try QRPp with a max power of 1 watt) and get gud.

>>1341388
A 1 W QRP transceiver would be fine with me. As for smart phone format we shouldn't forget that it is not that long ago since smart phones featured scroll wheels, pic. related. In fact it is far more comfortable to hold in your hand than most modern smart phones.

>>1341388

>>1341365
>Would transmitting on 20 with 100 watts heat the dipole enough to warm the wires and melt ice?
unlikely

>>1341209
>Mobile phone chip sets are highly optimised for low power consumption while delivering good DSP power
>I had hoped a DSP could do the filtering, obviously need a ADC.
Gays please stop it, DSP & EE/RF are way beyond your knowledge.

>>1341365
Run DC through it, assuming you have access to the ends.

>>1341388
>I thought the reasoning for this was due to the very limited selection of choices for finals on the hobby market
>implying implications
pls to be unpacking ja
>that don't require 9V-12V or are only good up to 1-2 watts TX
pretty sure 3S battery packs of useful amperage-hourage are not impossibly large, certainly smaller than Pic related, by which measure there already are HF trx small enough
>give up the physical buttons
okay, high-res encoders can take up a lot of space too, but buttons are thin
don't forget the slider form factor. great for RTTY

>>1341209
come back when you've got an Amateur Extra ticket

>>1341365
>>1341493
Hit it with a stick, for Christ's sake.

>>1341529
Too high up and the extension ladder is trapped in the garage.

>>1341538
Then you are SOL

>>1341559
Whatever was causing the SWR issue has returned to normal. I'm guessing the clump of snow bridging the elements electrically was blown off the connector.

>>1341538
Throw a stick at it, genius.

>>1341484
I have no idea about your preferences but I programmed DSPs for a living a few years ago. It is not too hard if you have done a bit of assembly programming.

>>1341523
>The world ends at the US coast
Why should I emigrate to the US to get another ticket when I have full privileges at home already??

>>1341856
>Why should I emigrate to the US to get another ticket when I have full privileges at home already??

That's right stay put we have enough shit here

>>1341523
If by "cell phone size" you mean bag phone or brick phone, then just get a Yaesu FT-817 (5.3"x1.5"x6.5") or an Elecraft KX2/KX3 (2.8"x5.8"x1.5"). Both of those can use internal batteries.

>>1341856
apparently, whatever Cracker Jack box country you got your ham license from doesn't require that you demonstrate the sort of knowledge of electronics it takes to homebrew
p.s. fuck off we're full

>>1341953
>get a
DROPPED

If we had 1kHz or so sinusoidal mains electricity and therefore no longer needed switched-mode PSUs for a lot of things (just using transformers and autotransformers instead), could we actually have less radio noise?

>>1342023
you're forgetting all the battery-operated devices, and other devices requiring multiple and/or regulated supply voltages, which are many
if we started treating electromagnetic sanitation with the same concern we treat foodservice sanitation or HOAs treat lawn maintenance, we could actually have less radio noise

>>1342031
Well I was assuming that most battery powered devices wouldn't have a significant effect on the noise since they're much lower power than things like computer PSUs and the like, but I guess with high-powered Li-ion devices about the place you never know.

>>1342053
I'm thinking smaller devices = smaller inductors = higher switching frequencies, often rnear or in the 160m band
among other losses, skin effect becomes interesting at 1kHz in power-line-sized wires. now maybe a dc grid would neatly fix the problems

>>1342066
Well the idea is that you don't run switched-mode PSUs and instead use transformers, so you don't have nasty square waves causing higher frequency harmonics. A DC grid would mean even more switched mode power supplies. It's not like there's much radio at 1kHz anyway, except for a few radio-determination and time-beacon bands.

>>1342206
iow you're ignoring battery powered devices which aren't going away. dI/dt is still quite large with some portable devices
anyway, to answer your question, yes, the bands would be slightly cleaner if people were willing to give up power efficiency, cost effectiveness, performance, and cool operation to switch over to a linear-regulated world. good luck with selling that

>>1333520
I'd move. The fight likely can't be won.

Operating on 70cm, I'm getting QRM that sounds like a high-speed diesel engine, typical of what you'd find in a fast motor launch. It comes and goes. Any time of day. I call it "motorboating" interference. Any idea what might be causing it? I get it fixed or mobile. I'm near a waterway and a coast guard station. No radar seen.

>>1342237
>linear-regulated
I never said anything of the sort. I was just implying that transformers at 1kHz are probably efficient enough per volume to compete with flybacks or buck converters.

>>1342247
8/8 troll, got me gud

>>1342023
>If we had 1kHz or so sinusoidal mains electricity and therefore no longer needed switched-mode PSUs for a lot of things (just using transformers and autotransformers instead), could we actually have less radio noise?
You know there is a thread for people like you, it's /ohm/, feel free to go there and share your genius ideas with the worlds. Anons there are unqualified enough to like them and discuss.

>>1342312
fuck no
send them to /g/

>>1341951
>That's right stay put we have enough shit here
I believe you.

>>1342003
>apparently, whatever Cracker Jack box country you got your ham license from doesn't require that you demonstrate the sort of knowledge of electronics it takes to homebrew
It does over here too, I just have no idea what made yo think I lack the knowledge.
>p.s. fuck off we're full
i consider that fully documented, thanks.

Past 350 posts and on page 10, anyone want to make a new thread?

>>1342731
Go on

the ARRL must get a shit ton of money selling mailing lists

>ARRL is pushing to give people with technician class licenses the ability to use HF digital and phone modes with up to 200 watts
>hear people say that doing so with kill local VHF/UHF activity similar to what happened in the UK when they added all mode HF up to 10 watts with their basic license
>think how much worse could that really be than it already is
>RepeaterBook shows the UK only has 543 repeaters in the country
>New York state has 760 repeaters with about 3/5 the land area of, a bit under 1/3 the population of the UK, and 18% more amateur radio operators per capita (effectively a bit over 1/3 the population of amateur radio operators)
>North Carolina has 583 repeaters with about 3/5 the land area, a bit over 1/8 the population of the UK, and 72% more amateur radio operators per capita (effectively about 1/4 the population of amateur radio operators)
>when adjusting for population of amateur radio operators, vs New York state or North Carolina the UK should have 2280-2332 repeaters
>when adjusting for repeaters per land area, vs New York state or North Carolina the UK should have 972-1267 repeaters
Jesus fucking christ, I guess we can expect local VHF/UHF local activity to reach levels of death we never previously thought possible in the future if the ARRL gets this passed considering that's 1/2 to 1/4 the number of repeaters (if the numbers actually happen to scale). On a side note, I wonder who will buy the rest of the 1.25 meter band because there's no way that will stay around and what other bands we'll see sold off due to lack of use.

Numbers are from RepeaterBook, Wikipedia for poplations and the size of countries/states, the FCC ULS, and http://www.arrl.org/news/ofcom-releases-uk-amateur-radio-license-stats

Its times like these 40 meters needs some hard core rag chewers to get going and utterly ignore the contestfags.

>>1342940
get these tech buyfags off my HF. code is more than enough for those scrubs

Some japs are truly funny animals
> Amelica
> Blavo
I fucking love them.

>>1343155
>>1343155
>>1343155