/HRG/ Ham Radio General

[Anonymous No.1369257]

In this thread we talk about:
- ham radio
- projects you have going on related to radio
- baluns and ununs on salvaged cores
- compact all-band antennas that fit into matchbox
- SDR
- discussing how should a new general trhead look like.
FAQ: In this thread we talk about:
- ham radio
- projects you have going on related to radio
- baluns and ununs on salvaged cores
- compact antennas for 160m band.
- SDR
- discussing how should a new general trhead look like.

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

FAQ: ftp://collectivecomputers.org:21212/Books/Cyberpunk/Tech/Radio/radio_FAQ_Preview2.htm
username/password is guest

[Anonymous No.1369275]

hey guys i built a 288' dipole, and its about 40-50 feet in the air. im getting absolutely not signal, a paper clip could do better. the antenna is made from solid copper in i have gathered from digging up wells. it is fed with 450ohm ladder line, going to a 4:1 tuner and finally to my radio. any suggestions?

[Anonymous No.1369277]

>>1369275
Why 288 feet?

[Anonymous No.1369279]

What is the appeal of amateur satellites and where would I start if I wanted to try it out? I know most satellites are meant for modes other than FM, how practical is it to try working satellites with portable equipment while hiking/camping? I also know you need to track the satellite orbits and need up to date SLE/Keplerian elements to accurately do so, but how out of date can you go before you start encountering problems? Can you ragchew on amateur satellites or are you only supposed to use them for basic contacts?

[Anonymous No.1369290]

>>1369279

https://www.youtube.com/watch?v=astteV2umOg

[Anonymous No.1369298]

>>1369290
Given those FM satellites are just basic repeaters rather than linear translators so only one contact can be going on at a time and they are only overhead for 10 minutes on average, any ragchew on those would seem to be extremely rude.

[Anonymous No.1369304]

>>1369298
It tends to be short conversations mostly.

HF and simplex is where the real ragchewers are.

[Anonymous No.1369314]

Was watching this on an AM net. Its this some Kahn type stuff?

>Carrier plus USB only

[Anonymous No.1369336]

>>1369257
The FAQ link is a bit outdated, it's already #6.

[Anonymous No.1369346]

>>1369279
I could listen to the ISS downlink with the built-in antenna of my portable all-mode radio, funny Doppler effect though. The Kenwood in the picture is dead now, no more digi mode.

[Anonymous No.1369535]

This is a reply to info dump about reactance at end of old thread >>1355280

Thanks for the info dump, I never knew anything about AC, only DC. I'll cap and save this.

So reactance is measured in ohms as well? When someone's talking about a radio "wanting to see 50 ohms" like previous post in old thread, they're talking about reactance and not resistance?

And do you mean that two wires just sitting next to each other in open air have effectively infinite resistance in DC (I know they do) but some amount of capacitance in AC?

Does placing an insulating material between the wires prevent any capacitance? Or does capacitance effect wires like this ladder line and coax and others that have two wires insulated from each other but still very near?

[Anonymous No.1369548]

>>1369257
>pic.
In what cases are an IC-7300 preferable over Elecraft KX3?

[Anonymous No.1369553]

>>1369548
>Power
>Waterfall display
>Local support

[Anonymous No.1369555]

>>1369403
>Shouldn't you..
You should, but you need not if you can tolerate a slightly radiating coax feed line. A literal monopole (one-terminal) antenna only exists as a thought.

[Anonymous No.1369559]

>>1369275
Have you tried bypassing the tuner on receive only as a test?

[Anonymous No.1369561]

>>1369555
Ah.

[Anonymous No.1369570]

>>1369559
i dont know if i can? the tuner i have is an mfj 901b. the next tuner i want to get has that option, but not this one.
besides that, this thing is pretty great
tiny too

[Anonymous No.1369835]

what do people think about this?
looking to start making baluns, but they are confusing to me for some reason.
https://www.ebay.com/itm/ET-51-MULTIBAND-BALUN-5-BAND-HAM-RADIO/323182635107?hash=item4b3f2fa863:g:lKMAAOSwx2dYGSXG

[Anonymous No.1369839]

>>1369835
5 Baluns with a central ground?

[Anonymous No.1369849]

>>1369839
im not sure. im using a fan dipole but only for 3 bands. i just hooked all the wires to the eye screws on the balun. wasnt sure if it was one balun or many, kinda want to open one up

[Anonymous No.1369882]

>>1369570
>has that option

Its not like you can't simply disconnect it all and stick the wires in the SO239 on the radio right?

[Anonymous No.1369887]

>>1369882
well im bringing the ladder line in to the tuner.

[Anonymous No.1369901]

>>1369835
Looks fishy to me, too expensive to be undocumented. Probably a single 1:1 balun with all dipoles in parallel. Needs a tuner of course.

[Anonymous No.1369909]

>>1369901
where would i get the toroid core from? i know i could buy one, but can i rip them out from transformers or something?

[Anonymous No.1369910]

Duck

[Anonymous No.1369923]

>>1369257
I know nothing of this and hate people in general. But it seems fun. One of the VERY few things i miss about being a super trucker.

There are only 2 guys in my town that got this stuff.

Been looking into broadcasting wifi to my workplace. Black hole for internet but have ATT here. I know 5g is out but likely i am a few years away from seeing it here.

Have unlimited 4g but horrible shit service out there. I hate att so fucking much for jerk dicking me around... i stream so much shitwhile busy working i keep frozen water bottles to set the phone on because it gets hot and stops charging.

>mfw att cucks remove all 3g shit to make room for 4g shit.
>mfw throttle at 22gigs
>mfw bought an alarm clock specifically so i can toss phone in the freezer and stream hd for nobody.

Anyway. I meant the tower i buy could serve both purposes.

Any anons know much about liniers? Used to see them in small truck stops but i thought they were illegal.

Cb puts out 4 watts by law but i ran an old cobra that puts out 150 watts. It works good but the mutherfucker has more switches, buttons, and knobs than the damned space shuttle.

If i get my ham liscense can i build a rig in my car that will fucking talk? Also, if i do it, would it actually fry other cb or is thst a myth?

[Anonymous No.1369926]

>>1369910
>lets
>get
>dangerous

https://youtu.be/0-Y2eM9KZ6Y

[Anonymous No.1369944]

>>1369909
PSU ferrite cores are too lossy.

[Anonymous No.1369957]

>>1369944
So what are you to use below 1MHz?

[Anonymous No.1369959]

>>1369923
>If i get my ham liscense can i build a rig in my car that will fucking talk? Also, if i do it, would it actually fry other cb or is thst a myth?
you can buy a rig. i doubt it would affect your cb
>>1369944
is there anywhere you can grab them from?

[Anonymous No.1369962]

>>1369923
For beaming the wifi, try looking in to a commercial solution like ubiquity.

linear amplifiers are illegal for CB use.

You could get/ build a rig that will _fucking_ talk. If you had a CB installed in your car, it is possible that you could fry your CB with the amateur radio.

[Anonymous No.1369970]

>>1369959
http://www.amidoncorp.com/
http://www.kitsandparts.com/
http://www.danssmallpartsandkits.net/
digikey.com
http://danscloseoutsandspecialdeals.com/index.html
https://www.fair-rite.com/
http://www.cwsbytemark.com/
http://palomar-engineers.com/

[Anonymous No.1369971]

>>1369970
Mods, I realise this post may look spammy. But it's the best answer to his question.

[Anonymous No.1369978]

>>1369970
Turns out amidon switched to a chinese supplier and may be selling bad toroids.
http://www.eham.net/ehamforum/smf/index.php/topic,85557.msg624623.html#msg624623


polite sage

[Anonymous No.1369999]

>>1369923
Use a booster.

[Anonymous No.1370015]

>>1369923
How far away is it? Do some I = P/(4πr^2) calculations to figure out how much of an amplification factor you need to get the intensity to be the same as it normally is when you're the maximum reliable distance away. In other words, the ratio of squares. If it's 10m to 5km, the ratio is (5000/10)^2 = 250,000W/W = 54dB gain. Of course you need this gain on both reception and transmission, so have fun figuring out how that works. Take apart a lower-power wifi booster I guess.

[Anonymous No.1370225]

I have a 5.8 GHz video signal from a drone that I'd like to extend to a longer range. If I stuck a repeater on a helium balloon and let it fly about 500 feet in the air, would that boost my range since you'd have Line-Of-Sight?

[Anonymous No.1370272]

>>1370225
Do 5.8 GHz video repeaters even exist?

[Anonymous No.1370296]

>>1370272

[Anonymous No.1370556]

>>1370225
Depends on how much other 5.8ghz is being spewed out from other ground stuff.

>Signal to noise ratio

[Anonymous No.1370837]

>>1370272
Not really. 5.8GHz video is analog and you cannot transmit and receive on the same band at the same time for $20. The 'repeaters' you can buy are all crossband transponders to 2.4GHz, which is heavily populated. I always had problems with moving analog video transmitters, even if line of sight. A WLAN link works much better if latency isn't an issue.

[Anonymous No.1370934]

>>1369257

[Anonymous No.1370936]

>>1370934

[Anonymous No.1370937]

>>1370936

[Anonymous No.1371015]

Is it possible to use multiband GPS signals as an alternative to ionospheric sounding?

[Anonymous No.1371028]

>>1370225
Ham license and run on atv frequency. They typically use 70 and 23 cm in this country.

[Anonymous No.1371045]

>>1371015
great question, wish I had an answer for you.

It's worth asking on an IRC channel or on stackexchange / reddit. Please post transcripts or a link if you end up doing so, I'd be interested in hearing the answer.

[Anonymous No.1371316]

>>1371045
I don't have a good impression of Reddit or Stackexchange in general, or are these sub categories any better than the rest?

My idea was that if most hams listened to L1 and L5 and reported this in to a central we would obtain a real time tomographic view of the ionosphere without having to do any sounding. The sounding itself is wasteful and really annoying for people trying to maintain communications.

I see this is a way to determine propagation issues in the E-layer but D-layer is harder. If we could also use L2 (hard problem) we might use a higher order polynomial to find the D-layer. Unconfirmed rumours is that L3 is meant for higher order polynomial recovery.

Presenting status on a map like Pic related would be a handy way to determine in real time where contacts are most likely.

[Anonymous No.1371319]

>>1371316
So if I understand right, you want to analyse the atmosphere (the ionosphere in particular) by comparing the amplitude of GPS signals from various angles and latitudes? Sounds very much like a CT scan, with the spacial fourier transforms and what.

[Anonymous No.1371328]

>>1371319
It is propagation delay between the same signal on two frequencies (L1 and L5, optionally L2) rather than amplitudes. Other than that you are correct.

All the parts are know, just like most inventions today it is just a question of putting parts from disparate fields (such as tomography in medicine) into a new field (radio comms and atmospheric sounding).

Most sites will see 10 - 15 satellites that move across the sky, leaving cross sectional traces in the model. Multiply by more sites and you will quickly get pretty good precision and a fine masked overview. Most moving things have GPS. Many fixed installations such as base stations also use GPS (for timing). Hams use it for GPS disciplined oscillators. Unfortunately L5 data is not available in most receivers yet though Broadcom launched a new GPS chip that does.

Something for the next Elecraft K4?

[Anonymous No.1371344]

>>1371015
>alternative to ionospheric sounding?
No, supplement.
Ionospheric Sounding Using Real-Time Amateur Radio Reporting
onlinelibrary.wiley.com/doi/10.1002/2014SW001132/abstract

[Anonymous No.1371349]

>>1371328
I hope you're not implying that you measure the differing speed of light through the ionosphere at different frequencies, but instead some form of frequency dependant scattering.

[Anonymous No.1371363]

Dumb question here as radio waves are complicated. I have a Uniden 436 HP scanner. I'm using an offset dipole which is better than a whip but its limited on freq. range. My question is when I buy a discone antenna why cant's I use a splitter and use both antennas at once? If the explanation is over my head you can just say "No"...Thanks, wish I knew a Ham guy would love a new hobby...Thanks in advance!

[Anonymous No.1371372]

>>1371363
i believe you can. i think you need a bit more than a t connection, you need something like what they have for splitting tv connections.
i might be getting confused with using multiple scanners on one antenna
what kind of dipole?
discone was my first antenna, it does ok, but if youre just listening near 155-146mhz, a jpole would be a lot better

[Anonymous No.1371376]

>>1371363
you probably could, but the new antenna array you've made is now sensitive to direction and phase. this article discusses the issue as it applies to 11 meters, scale these examples down according to the wavelength(s) you're trying to receive
http://www.bellscb.com/cb_radio_hobby/antennas/antarray.html

[Anonymous No.1371378]

>>1371349
But I do
http://www.navipedia.net/index.php/Ionospheric_Delay
>As the ionosphere is a dispersive media, the GNSS signals refraction depends on its frequencies (as the squared inverse). This dependence on the signal frequency allows us to remove its effect up to more than 99.9% using two frequency measurements (see Ionosphere-free Combination for Dual Frequency Receivers). But, single frequency receivers have to apply an ionospheric prediction model to remove (as much as possible) this effect, that can reach up to several teens of meters (see Klobuchar Ionospheric Model and NeQuick Ionospheric Model).

[Anonymous No.1371405]

>>1371372
Hell I deleted the post..Hate feeling stupid

I'm using a home made offset dipole using 3/4" copper. It does great for certain freq's. I'm pulling State Patrol from 200 miles. The antenna is 20' up on a pole and my house is the highest point around so that helps. But I noticed that if I use the small whip I get channels that the offset dipole misses all together. I need to do some reading. Its all Chinese to me at this point. Thanks for the help

[Anonymous No.1371411]

>>1371376
Thanks anon will read

[Anonymous No.1371415]

>>1371405
whats the antenna supposed to be cut for?

[Anonymous No.1371431]

>>1371378
Oh, via refraction and hence path difference, not via straight-path speed difference, which is probably more reasonable. I'll do the algebra now:

[Anonymous No.1371441]

>>1371431
aaand I've the same intermediate variable in two seperate tan() functions with no way to rearrange for them so that I can substitute the function for that variable in the time equation to get time as a function of the absolute angle from the satellite to the ground.

[Anonymous No.1371446]

>>1371431
Doesn't refraction change the speed of light in the medium?

[Anonymous No.1371449]

>>1371431
>>1371441
fucking nerd. stop making me realize how stupid i am

[Anonymous No.1371451]

>>1371415
I read an article that said this setup was great for all around use on a scanner. Granted I don't know shit to be honest about RF. Here is a link someone suggested in the article.

https://wiki.radioreference.com/index.php/Homebrewed_Off-Center_Fed_Dipole

[Anonymous No.1371463]

>>1371446
Well yes, but it will also make the light take a non-straight path. By either accounting for this difference in path or not you can calculate what kind of difference in measured time it would make. Or at least attempt to. But either way, since 20,000,000m is our minimum distance, and the speed of light is 300,000,000m/s, the time it takes for a signal to arrive will be 2/30 seconds, which is about 70ms. So multiply that by |n1-n2|/20 and you'll get some idea of what sort of numbers to expect. 20 is the ratio of satellite altitude to max ionosphere altitude. The ionosphere also has an index of refraction less than unity, which is a little bizarre. I can't find any values for the index of refraction online (nor do I know what to do about their imaginary part, does it change the phase or polarisation?)

[Anonymous No.1372152]

>>1371405
>State Patrol from 200 miles
From a height of 60 feet the horizon is 10 miles away.
>>1371451
Like you, the author avoids mentioning a frequency.

[Anonymous No.1372178]

>>1370225
Legit awesome idea anon.

If it works build a heavy lifter and make the load a giant fucking battery pack set that bitch to hover and go nuts

[Anonymous No.1372179]

>>1370837
Transmitter/reciever run 2.4ghz. Is why the video feed is 5.8.

[Anonymous No.1372202]

>>1372152
>my house is the highest point around
>r is constant
pick only one.

>>1372179
>implying there's not more than 5MHz bandwidth in the 2.4GHz band

[Anonymous No.1372205]

>>1372152
Like I said before my farm is the highest point for miles and the antenna is on a mast. I ask a simple question. I wont stoop down to your level with some snide remark. Just stated the truth. Have a great day!

[Anonymous No.1372388]

Are the 33 cm band and 23 cm band used widely used in the US or are they just used in certain larger cities? I'm setting up an RTL-SDR to do band surveys to find out where there's activity and I've heard that the 33 cm band is just a dumping ground where amateur radio enthusiasts are secondary users to tons of shit (which I figure may lead to me digging through a lot of signals I wouldn't care about possibly to find nothing) and the 23 cm band is only used in large cities. I should note that I'm doing my band surveys in a few different places with the highest populated place being a city of 50k.

[Anonymous No.1372400]

>>1372388
I figure I should also ask about the 1.25 meter band. I have about 30 hours of band surveys over a period of a few days and haven't seen anything on it yet (though I don't think I've done anything past 2 PM yet).

[Anonymous No.1372431]

>>1372205
Thanks for the 200 (s)miles, fairytale-kun.

[Anonymous No.1372472]

>>1372431
>filename

I'm guessing whatever this "State Patrol" is won't be bouncing off the ionosphere?

[Anonymous No.1372491]

>>1369257
ham radios is dead, bury it.

[Anonymous No.1372498]

>>1372491
Well it's fucking mandatory for using a high altitude balloon or long range drone usage.

[Anonymous No.1372646]

>>1372498
In the UK, Clause 2(1)(c) of the Amateur Radio licence explicitely prohibits the operation of any Unmanned Airborne Systems (UAS), including balloons (tethered or untethered). Does the FCC/FAA handle this differently?

[Anonymous No.1372658]

>>1372646
Must suck to be in the UK. On the wikipedia page for high altitude ballooning half the page is dedicated to amateur radio use on these balloons. In particular, APRS is an amateur radio telemetry system that transmits on the 2m amateur band that is frequently used for high altitude ballooning.

[Anonymous No.1372693]

Just wanted to thank you guys for answering my question. Since my offset dipole is picking up the highway patrol 200 miles from my house and you thinks it's BS that tells me this antenna is kicking ass. Thanks Again I knew I built an awesome antenna.

[Anonymous No.1372698]

>>1372693
you sure it's not picking up a repeater?

[Anonymous No.1372785]

>>1372658
From the quoted text my impression is that they are OK with using ham privileges for ham purposes but not where the end purpose is to drive a drone at extended range.

If, instead, the purpose was to launch a balloon at great altitude and use it as a relay (say hang a REALLY long copper wider down as a 2200 m band antenna and use a different band for relay/control they might be OK with that. I think.


Mmmm, interesting idea...

[Anonymous No.1372824]

You can do Canadian ham radio practice exams to see if you'd pass:

http://www.ic.gc.ca/eic/site/025.nsf/eng/h_00040.html

[Anonymous No.1372928]

>>1372785
>they might be OK with that
Even if, the physics certainly isn't. A hanging wire alone is not an effective antenna. I'd suggest to tether the balloon and keep the station on the ground, including the necessary extensive network of (burried) grounding radials. Unless the CAA (FAA in the US) intervenes reminding you that a ham radio licence is not a 'licence to kill', this could be done.

On the continent ARTOB (amateur radio transponder on bolloon) was popular in the late 1960's. The balloons carried a 70cm uplink 2m downlink transponder, reached a height of about 30km and the flight time was 2..3 hours. After that, fox hunt.

Meanwhile such a project requires extensive planning, flight path simulation, notification, documentation, permissions, insurance, fees.. The most active groups are now high school students and teachers.

Image: Balloon, parachute, radar reflector, payloads.

[Anonymous No.1372945]

>>1372928
>A hanging wire alone is not an effective antenna.
Why not?

[Anonymous No.1372962]

bands are SO shit lately, really sucks. Gives me an incentive to try to learn code tho

[Anonymous No.1372975]

>>1372824

[Anonymous No.1373009]

>>1372945
No current path.

[Anonymous No.1373032]

>>1372388
I decided to do a short hour and a half band survey of the 33 cm band and I think it's safe to say it isn't worth spending my time on as there's no way I'll see a signal that may be of interest to me through all this shit and I highly doubt there's a local 33 cm contest going on right now given there are no repeaters on that frequency listed in this area.

[Anonymous No.1373080]

>>1373009
>what is a 1/4 wave monopole
You don't need to be grounded to the actual planet earth to transmit radio waves, there isn't a high altitude balloon out there that's been run with a tether.

>After that, fox hunt
APRS helps with that as it will transmit GPS coordinates, among other things. It's a nodal network (provided you have people with active APRS transceivers nearby) so even if you can't receive the beacon's signal directly, someone else will and you can get it relayed from there. At least I think so.

[Anonymous No.1373205]

>>1372824
79/100 for my half-arsed attempt, but I got a lot of the regulation and policy ones wrong as I'm not a leaf and don't know leaf-specific laws

[Anonymous No.1373232]

>>1372824
That's how I practice for my exam. Got in the 90s% when I wrote it

[Anonymous No.1373248]

>>1373080
>1/4 wave monopole
Basic misunderstanding, deception by appearance, has been explained often enough, scroll back. - 2200m needs no high altitude, context. - There was no GPS at that time, context.

[Anonymous No.1373296]

>>1373248
Oh yeah, 2200m. I mean sure they didn't have simple GPS modules like that nor anything resembling APRS back then, but I was just stating that now days we do have things specially made for that.

[Anonymous No.1373322]

>>1373248
The altitude was just to get enough distance for a long wire, which is easier to hag down than erect upwards.

In any case you would probably need a counter poise which can be shorter and upwards,

[Anonymous No.1373351]

>>1373296
Yes, the ARTOB shown in the image was fully equipped for flight path tracking. It still had an autonomous robust VHF fox hunt beacon for the recovery scouts, you never know where it really lands (trees? lakes?) and what is still intact and how long. In this case the 'bounty' was a non-descript scientific payload supplied by a federal aerospace agency.
>>1373322
My post was also addressing the legal situation in the UK. You have a _manned_ station on the ground at a fixed and known QTH and the balloon merely holds your antenna. If you can have an unmanned free floating system, a simple configuration could be: balloon - quarter wave wire - transmitter etc. - quarter wave wire - weight; essentially a vertical half wave dipole, no ground required.

[Anonymous No.1373455]

>>1373080
A monopole is not just a hanging wire. See below.

>>1373351

I disagree with the statement "essentially a vertical half wave dipole, no ground required."

If an antenna is unbalanced, it requires a radial system or counterpoises.

I am unaffiliated with the following website:
http://www.sgcworld.com/radialstechnote.html

2. A and B. appear at face value to be correct.

The following website appears to indicate the same:
http://faculty.frostburg.edu/phys/latta/ee/station/antennas/antennas.html

[Anonymous No.1373508]

>>1373455
>If an antenna is unbalanced
The one I described is fully symmetrical and thus perfectly balanced.

[Anonymous No.1373520]

My neighbor is a hamfag his house looks like shit with all his antennas and shit everywhere. I snuck over one night and shoved a straight pin in all his coax and broke them off so you can't see them. He's been in and out all day looking his shit over. Too funny

[Anonymous No.1373629]

About the pixie (Pic.) I wonder, what is the audio output like? What is the bandwidth like?

I am still thinking of attaching it to an Android app.

[Anonymous No.1373987]

>>1373629
Low headphone level, bandwidth adequate, clicks on keydown.
Pic: http://www.bandconditions.com/

[Anonymous No.1374349]

>>1373987
How many kHz audio bandwidth is available when receiving?

Also, is the level at +IN on LM386 sufficient to drive the mic input on a mobile phone without amplification?

BTW nice diagram.

[Anonymous No.1374361]

[Anonymous No.1374389]

>>1374361
Ah. Antenna pr0n. Perhaps I should share a few images?

[Anonymous No.1374407]

>>1374389
I'd definitely enjoy that

[Anonymous No.1374459]

>>1374349
Don't know about the noise bandwidth (C9) but the signal is between zero and a kHz or two, depending on how far you pull the crystal. The +in level may be a bit weak but you can always attenuate the phone out signal.

[Anonymous No.1374738]

>>1374407
Let us start with the legendary Wullenweber (tragically my back yard is too small for it).

Perhaps one that works on while octaves on HF bands would be more compact...

[Anonymous No.1374751]

>>1374738

[Anonymous No.1374983]

>>1374389
>Antenna pr0n
Have some coax pr0n.

[Anonymous No.1375018]

>>1374983
I've always heard that called a waveguide at that size.

You also need to monitor the air pressure
In it and keep it pressurized with dry air.

[Anonymous No.1375051]

I like SWLing (and monitoring in general; I'm a lurker by nature) and I'm looking at actual rigs for when I have some dosh in my pocket; does anyone have experience with the KX2, KX3 or Buddipole? I was also thinking about a wellbrook or maybe a boni-whip.

[Anonymous No.1375077]

An article about balloon telemetry using the 2 m band:
https://www.rtl-sdr.com/creating-a-high-altitude-balloon-telemetry-system-with-raspberry-pi-rpitx-and-rtl-sdr/

[Anonymous No.1375202]

>>1375018
is it still a waveguide if it has a central conductor rather than a dimensioned cavity?
I vote no

[Anonymous No.1375212]

>>1375018
No, different principles. A waveguide has no second conductor.
The 10 cm(?) coax was for analog VHF TV. It was filled with dry nitrogen, sealed and left alone for a decade or two. The smaller one is for UHF digital TV.
Picture: a coaxial cage line transporting 2000 kW to a 300m medium wave antenna.

[Anonymous No.1375295]

>>1372388
>>1373032
After reading these posts I decided to try doing a band survey of the 33 cm band to see how bad it actually is. While I didn't see any signals that were longer than about 20 seconds max at a time with anything else near them that would look like normal voice traffic on the waterfall, there are a ton of small blips under 20 seconds long everywhere that are making me wonder if anyone has ever played around with morse burst encoders or high speed digital modes on the band for privacy purposes as such a short transmission would blend in with all the other normally occurring signals.

[Anonymous No.1375505]

Are there standards for measuring radio noise at a wide range of frequencies? With a well-characterised antenna you'd just be measuring the amplitude of noise when tuned into different frequencies, multiply that by the antenna's efficiency at that frequency, but you might also want to measure noise at different polarisations (north-south, east-west, up-down) so you'd need to know how well your antenna picks up those polarisations, and I know the surrounding terrain will make a difference.

[Anonymous No.1375741]

>>1375295
>band survey
>>1373032
>band survey
>>1372400
>band surveys
>>1372388
>band surveys
Interesting.

You can find some good info about the situation on the 33 cm band at
http://www.repeater-builder.com/tech-info/900mhz-frequencies-to-avoid.html

There once was a 220/900 MHz dualband radio (pic) but it has been discontinued years ago.

[Anonymous No.1375813]

>>1375212
I saw similar to that pic on a 5kw station once. There was a dead bird stuck in it with a hole burnt in it where it shorted to the centre conductor. That site is now gone and the station runs diplexed with another station.

[Anonymous No.1375817]

>>1375741
>discontinued

Neither of those bands are amateur in my country. I guess radio manufacturers targeted a wider market.

[Anonymous No.1375839]

>>1375817
222..225MHz and 902..928MHz is only allocated in Region 2.

[Anonymous No.1375890]

I have a baofeng uv5r that I plan to mount in my vehicle since I never have keyed up and probably won't ever. I want to reuse my Nagoya na-701, but I got some worries and questions.

Is a sma fitting strong enough to support a ~14" rubber ducky at 65-70 mph? or contact from trees and brush?
Does the amount of adapters/connectors effect receiving quality? sma>so239>so239>sma so I am able to upgrade later
Any good low/middle range 2m/70cm mobile radios and antennas?
Is the 6m (50-54 mhz, I only have technician license) any good? I might save up for a decent one if so.

[Anonymous No.1375919]

>>1375890
>Is the 6m (50-54 mhz, I only have technician license) any good? I might save up for a decent one if so.
What on 6m? If you're wanting repeaters or FM simplex, then repeater availability varies a lot depending on the state and FM simplex most likely varies with that. In Nebraska for example only one of the 158 repeaters in the state is on the 6 meter band, while in North Dakota 4 of the 66 repeaters in the state are on the 6 meter band (giving them comparable representation to repeaters using D-Star or other specific digital voice implementation in more populated states).

[Anonymous No.1375922]

>>1375741
I opened up the waterfall plot I made in Gimp and marked off the areas where those frequencies were, even still there's a lot of blips everywhere and I don't think people's lower power devices would be powerful enough to cause imaging issues.

[Anonymous No.1375923]

>>1375212
You an engineer?

[Anonymous No.1375946]

>>1375919
>What on 6m?
I assume singals can go further than 2m at the same power output.
I [currently] live in Arkansas which upon a quick lookup has 10 repeaters open and may travel to; texas (26), Tennessee (16), Oklahoma (4), Colorado (5) and Wyoming (3). Even if it has no purpose to me, I find it interesting.
Also since lots of HF radio come with 6m support, which may encourage me to up my license. Plus I've read that it has propagation modes of both VHF and HF.

[Anonymous No.1376013]

>>1375946
>Also since lots of HF radio come with 6m support, which may encourage me to up my license. Plus I've read that it has propagation modes of both VHF and HF.
If you're looking at using the 6 meter band for fun with long range propagation, you're going to want something that can do SSB voice. I don't think many people use FM on the 6 meter band outside of repeaters.

[Anonymous No.1376475]

This solar weather is fucking killing me.

[Anonymous No.1376533]

>>1376475
Time of a Quiet Sun, but a sudden flare is always possible. Image: Tail end of Solar Cycle 24, the weakest for more than a century. SC 25 is predicted to be similar or weaker. In about five years we will know. (Source: http://sidc.oma.be/silso/ssngraphics))

[Anonymous No.1376535]

>>1375813
A US Coast Guard DGPS beacon site was experiencing mysterious SWR issues around sunset almost every night..until someone went there and observed this.

https://en.wikipedia.org/wiki/Differential_GPS
https://www.navcen.uscg.gov/?pageName=dgpsMain

[Anonymous No.1376537]

How do I identify torroids? There seem to be many with similar dimensions

[Anonymous No.1376559]

>>1376537
toroids.info

[Anonymous No.1376560]

>>1376475
This regular weather is fucking killing my wifi. How does that even happen? The router is on the ceiling in the next room.

[Anonymous No.1376603]

>>1376535
>Top loading

[Anonymous No.1376618]

R8 m8’s

[Anonymous No.1376865]

>>1376618
Need to separate the museum from the working rigs. Show us you /DIY/ transmitter.

[Anonymous No.1376866]

>>1376618
Jelly/10

I wish my house wasn't surrounded by fucking power lines.

[Anonymous No.1376868]

>>1376618
MEGA DIAMONDS HARDON

[Anonymous No.1376885]

>>1376866
just cut them down. dont they know you need to play radio?
power companies can be so rude sometimes
i can loan you my blades if you want, pic related

[Anonymous No.1376887]

>>1376618

[Anonymous No.1376890]

>>1376887
im gonna guess this guy died in a fire

[Anonymous No.1376892]

Hi all,

i'm new in ham radio, i got my belgian ON3 license from 2 days now. I don't have make anything right now.

What can i do without real stuff right now?
What kind of stuff do you recommend to start ?

The only stuff i have is Baofeng uv-5r

[Anonymous No.1376947]

>>1376892
You can listen to local FM simplex and repeater traffic. Just don't program too many in since Baofeng's can only scan 3 channels per second, so with say 21 channels to scan it's possible to completely miss a transmission under 7 seconds long.

[Anonymous No.1377084]

>>1372646
The FCC (as far as drone usage) requires line of sight and actual site at all times :ie If you use a headset that allows you to see what the camera sees, like goggles, then you don't have actual site and must have someone with you to keep eyes on the drone. This is both private and commercial, and applies unless you have a qualified flight plan. With the flight plan and air clearance or ROS then you can do so. It isn;t that hard to make and file the plan and get approval. I am a licensed drone operator.

[Anonymous No.1377102]

>>1377084
Ah, nice to know. But I suppose that doesn't apply to high-altitude balloons.What kind of drone operation do you do, filming?

[Anonymous No.1377127]

>>1377084
One local drone operator in my country has flown them over 90km away.

[Anonymous No.1377138]

>>1377084
>licensed drone operator
107 or 336?

[Anonymous No.1377147]

>>1376892
You can easily make a crystal radio set. There are a few suggestions in the FAQ.

[Anonymous No.1377183]

>>1377084
>I am a licensed drone operator.
nigger anyone can be a license drone operator these days it's a stupid test.

[Anonymous No.1377261]

>>1377183
>stupid test
How long did you prepare and what was your passing grade?
How much did you have to pay for the certificate?
When is your next recertification?

[Anonymous No.1377788]

>>1369257
I just bought this as my first T1 & T2 DMR radio, pretty cheap at £60.

Have I dun goof'd?

Looking at setting up a codeplug for it before it gets here - anyone had any experience with the GD series?

[Anonymous No.1377850]

>>1377788
Congrats and happy beta testing
Radioddity downloads and
Facebook Radioddity Two Way Radios

[Anonymous No.1378474]

Ham Radio Workbench Podcast
http://hamradioworkbench.com
HRWB045-DMR Basics Part 1
HRWB046-DMR Basics Part 2
HRWB047-Yaesu System Fusion

[Anonymous No.1379074]

so anyone have plans for a 5v 2.5a powered MURS or FRS radio that I would be able to power off a USB battery bank/solar panel?

[Anonymous No.1379103]

>>1379074
No, because it isn't legal to use non FCC certified equipment on those frequencies. Not to mention the issue of radios being harder to home build the higher the frequency you're trying to use, so the people with the skill/equipment to do so wouldn't be wasting their time on an FM transceiver for frequencies they can't legally use.

[Anonymous No.1379109]

>>1379103
well then, what service would a home built kit be legally usable then that doesn't require a license, and would be power-able off USB level voltages?

[Anonymous No.1379118]

>>1379074
>2.5A
>USB
Gonna trigger the overcurrent shutoff unless you're using a generously rated chinese power bank with paralleled ports or dual plugs.

[Anonymous No.1379119]

>>1379109
Why not just get a license, considering there's tons of resources for building your own equipment to work on the amateur radio bands?

[Anonymous No.1379126]

>>1379119
because the old guy next door is the local examiner.

[Anonymous No.1379138]

>>1379126
Drive to the next town over and take the test there? I actually had to drive about an hour to the place where I took my test since that was the only place that had tests on days I didn't have to work.

[Anonymous No.1379174]

>>1379126
That could also go in your favour if you can get along with him.

There is a guy around here with a rather low IQ. He got interested in CB and the old ham 3 doors up helped him study. He got his base level license. idk if he is smart enough to go further but time will tell.

[Anonymous No.1379262]

>>1379109
>and would be power-able off USB level voltages?
you can just convert to a higher voltage to power some off the shelf unit

[Anonymous No.1379352]

I want to output a FM signal from my SDR. How do I convert e.g. a .wav file properly? What modulation equation do I use exactly? How can I take the .wav file, and have it play on some frequency? I'm using C by the way.

[Anonymous No.1379355]

>>1379352
You mean use your SDR as a transmitter or take a signal you received via the SDR and transmit it separately? I don't believe the former is possible, while the latter is somewhat of a challenge. If you just want to transmit FM from stored music there are far easier ways of going about it, including buying one of those car audio senders and amplifying it. There are some pretty primitive FM transmitters out there.

[Anonymous No.1379553]

>>1379109
>legally usable
LowFER (Low Frequency Experimental Radio)
https://en.wikipedia.org/wiki/LowFER
FCC Part 15.217 Operation in the band 160–190 kHz.

[Anonymous No.1379719]

>>1379352
You could use GNU Radio Companion to do it, instead of C. It's pretty straightforward, and I believe there's at least one example for FM transmission over an SDR device.

[Anonymous No.1379723]

>>1379138
>tfw taking the technician test next week and it's administered 300 feet from home

[Anonymous No.1379849]

>>1379723
How would that make it easier?

[Anonymous No.1379864]

Which one of those would be the best ducky replacement for my innawoods handy, Nagoya 701, 717, or 771R?

[Anonymous No.1379940]

>>1379849
It's relief from when I found out the test would be within walking distance, because I didn't want to have to drive an hour away.

[Anonymous No.1379961]

>>1379355
I just want to transmit audio from my SDR, it's definitely possible.

>>1379719
I've already done it with GNU Radio, but that sadly teaches me nothing even though it's very easy.

How exactly do I "Wideband FM Transmit"? Even a point to the right direction would be a blessing.

I just wanted to learn more about radio frequency security, but it turns out I'm going full telecommunications engineer now.

[Anonymous No.1379980]

>>1379961
>Wideband FM Transmit"?

Shit tier: pifm

Semi shit tier: bh1417 or variants including most chink eBay devices.

For better tier stuff lurk radio necks with your bs filter activated.

[Anonymous No.1379983]

>>1379864
771 with a tiger tail if youre really on the fringe of a repeater

[Anonymous No.1379985]

>>1379961
i dont think you can transmit on the real cheap ones. i think you can do very low power on the hack rf

[Anonymous No.1379999]

>>1379983
I'm only considering 771R because the full-length is too impractical to carry in my scenario. I saw a few people mention that you need to be extremely careful extending and folding it, but not really substantiated by "professional" reviews. Still, a bit of concern.
Don't think I need tigertail, and with 771R wouldn't that turn it into a full-wave for 70cm anwyay?

[Anonymous No.1380002]

>>1379999
i have the 701 on the baofeng i carry to work, it doesnt get in the way. i would never buy a telescoping whip, im guessing i would snap it within a day.
i dont think it would, but im not sure. i do know when i was hiking trying to hit repeaters the tigertail got me in, without it i couldnt even key up the repeater

[Anonymous No.1380015]

>>1379999
>Don't think I need tigertail
Tail first, new antenna later: HRWB044-Basic HF Antennas. Highly recommended. Like with the other three podcasts (DRM)), you can skip the intro without missing much of what this edition is about. You will understand why there is no single pole antenna.

[Anonymous No.1380091]

>>1372962
What's your qth and do you know any code at all?

[Anonymous No.1380697]

>>1380091
Planet Earth and dress code.

[Anonymous No.1380860]

the ARRL license exam questions get changed this summer right? what date? I want to study up and get all 3 before the material changes.

[Anonymous No.1380863]

>>1380860
found it, it's June 30th for the Technician exam

[Anonymous No.1380874]

Total newfag to radio, found this on the curb on junk day. Wat do?

[Anonymous No.1380880]

>>1380874
Lucky cunt

[Anonymous No.1380910]

>>1380880
I'll take that as a good thing, I really don't want to break it.

[Anonymous No.1380934]

>>1379980
I've already used PiFM and rpitx. The thing is I already have an SDR capable of this, and I want to use that instead of the RPi3's shitty oscillator hack by learning some radio theory.

>>1379985
The HackRF is capable of it, but so is any SDR with TX capabilities. I can blurt out random shit (effectively noise) into the air, but I can't actually do frequency modulation (FM) in good old C or Python. GNU Radio Companion does it for me, but again, it teaches me nothing.

Man, RFcomms is hard.

[Anonymous No.1380951]

>>1380874
>ssb
noice

[Anonymous No.1380980]

>>1380874
>found this on the curb
Give it back.

[Anonymous No.1381051]

>>1380860
>>1380863
>I want to study up and get all 3 before the material changes.
That's what I thought too, but the amount of changes is so minuscule that it wouldn't really matter, most changes are just rephrasing or changing numbers in some questions.
Anyway, I'm doing my Technician and General next week, and Extra in June maybe (not like I have the gear to make any use of the privileges yet).

[Anonymous No.1381088]

>>1380874
>found a 10 meter/12 meter band transceiver by the curb as junk
Wow, I knew band conditions were bad but didn't think they'd drive someone to do something like this. You can build a transverter so that you can use it on a band that would actually be active now, or you can just sit on it for a while, those bands should by open again some time before 2025.

[Anonymous No.1381659]

>>1380874
god DAMN IT TYRONE

[Anonymous No.1381701]

>>1381088
Could be diseased estate. Some relatives throw out stuff to just clean a place out fast to sell it.

That may have belonged to someone illegally using it on 11 metres too.

[Anonymous No.1381707]

>>1381701
One other fun story.
>work at electronics shop
>old grandma walks in with IC735
>Impulse bought at thrift shop for $15
>wants a plug to plug it into main so she can listen to fm radio
>explain how this will not work
>offer her $20 for it
>she takes it instantly
It turned out to have a fault but may get around to fixing it one day. It does work on some bands though.

[Anonymous No.1381766]

Lot of radio/ham relevant updates on the FTP site:
ftp://collectivecomputers.org:21212/Books/Cyberpunk/Tech/
(also check the sub directories)

[Anonymous No.1381888]

>>1381766
Tech/Radio/Electronic_Warfare/ is new

[Anonymous No.1381902]

>>1381888
>gendered ship pronouns meets the modern era
What a world we live in.

[Anonymous No.1381987]

>messing around doing band surveys with my RTL-SDR
>decide to turn the antenna horizontally to see if what it picks up changes
>notice some activity on the repeater output section of the 2 meter band that I hadn't seen before
>checking online, the nearest repeaters operating on those 2 frequencies are ~90 miles away and a little over 200 miles away
>the ~90 mile away repeater was picked up consitantly throughout the day
What the fuck? How common are repeaters that aren't registered online?

[Anonymous No.1382145]

>>1381987
I think it would be interesting to mount a long Yagi on a servo driven table and scan slowly around the horizon, flipping between H- and V-polarised, to see all that is out there. You could turn it into a polar plot where angle is spatial angle and radius relates to frequency.

Colour H- and V-polarised signals in red and green channels to resolve the data.

Colour DF does colour coded angles, sometimes with 180 degrees ambiguity, not sure why just sometimes.

[Anonymous No.1382148]

>>1381987
That can happen easy if there is an inversion. The other day I heard a vk7 talking to vk3 with 5 watts on 2 metres.

[Anonymous No.1382220]

>>1382148
That is probably it. The 50 m opened up, big time:
http://mailman.qth.net/pipermail/elecraft/2018-May/255656.html

[Anonymous No.1382221]

>>1382220
* 6 m (of course). Bah.
Have a nice pic. as compensation.

[Anonymous No.1382667]

Anything new on UVB-76?

[Anonymous No.1382682]

>>1382667
>UVB-76

http://argon.printf.cc:8000/buzzer.ogg

[Anonymous No.1382699]

>>1382667
Oh people here still care about that? After some reading I don't think it's anything special, just a reservation of a radio station for emergencies, but their apparent use of a microphone and speaker to transmit the signal instead of wiring it directly is certainly odd. Even more so that they've kept the system the same even after moving location only a decade or so back. Perhaps a failsafe, in the case the station is reserved for use transmitting launch codes/signals? Some funky duplex setup?

>>1382682
Thanks for that link, know where its being received from?

[Anonymous No.1382873]

>>1382699
>received from?
http://fasoland.pl/
receiver located in Silec, Poland, QTH KO04SD
http://argon.printf.cc:8901/

[Anonymous No.1383261]

>kind of want to try playing around with HF
>only have a technician license for CW on the 40/80 meter bands
>not interested in digital modes
Given the current band conditions, is it even worth upgrading to general right now or would my time be better spent learning morse code?

[Anonymous No.1383387]

What police scanner would lads recommend? (under $300)

[Anonymous No.1383394]

>>1380874
refurb and sell for big bux

[Anonymous No.1383397]

I live in the UK and would like to get started with DMR radio. I don't have an amateur radio license. Is it legal for me to use a DMR radio for listening only and how do I do about this?

I've aware that the TYT MD-380 is quite a popular radio and has community developed firmware available. Assuming it's legal for me to listen only without an amateur radio license, what values do I program in for items such as callsign/radio id/radio name etc.

[Anonymous No.1383398]

>>1383397
>Is it legal for me to use a DMR radio for listening only and how do I do about this?

In the US its legal, as for the UK probably not seeing as you unironically need a license to operate tying your boots.

[Anonymous No.1383411]

>>1383397
>what values
Nothing, leave blank.

[Anonymous No.1383425]

>>1383387
you country is digital i presume?
>>1383397
in murica you can listen to anything you want, at home. having a scanner in your car in certain states can get you into trouble if you dont have your ham license.

[Anonymous No.1383428]

>>1383261
nigger, get your general. we need more of us on the air

[Anonymous No.1383434]

>>1383425
I live in the US.

[Anonymous No.1383448]

>>1383434
if youre in a city you probably want a digital scanner. but look it up on radio reference

[Anonymous No.1383465]

>>1383425
>in murica you can listen to anything you want, at home. having a scanner in your car in certain states can get you into trouble if you dont have your ham license

Like a pig gives a flying rats ass about a ham license omg I about spewed coffee on that one

[Anonymous No.1383466]

Irony
Be a fat toadlette hamfag with radio that can reach around world
Spend all day posting on 4shit

[Anonymous No.1383625]

>>1383466
This. We never talk.

[Anonymous No.1383671]

>>1383261
given the recent movement by ARRL to prompt the FCC for more tech HF privs, consider waiting... That being said, study anyway! it's fun and you can learn a lot.

[Anonymous No.1383675]

>>1383465
just telling you from experience in jew york
>>1383466
i cant reach my ham equipment over this computer, i have too much piled up
>>1383671
fuck that. why would we give tghem more for the first license? earn that shit, nigger

[Anonymous No.1383677]

Is a Quadrifiliar Helix Antenna better for GPS than a patch antenna? I would have thought it would reject first order reflections due to polarisation but somehow the patch antennas get good reviews.

How does the receiver compensate for reflections?

[Anonymous No.1383680]

>>1369279
> What is the appeal of amateur satellites and where would I start if I wanted to try it out?
Working them is difficult from a pure operating perspective. Due to the huge footprints and many operators working, there is an extreme obligation to operate efficiently such as to not ruin the pass for others. Unless you have a lot of money for az/el rotators and good feedline and expensive radios, you are probably going to be operating portable, which means no notepad and paper, just you and a portable handheld radio and a portable handheld antenna. Depending on what helps you, you may need an accurate wristwatch, you may need a compass, you may need a voice recorder. You need to be on your toes and on your bearings, you need to know where the satellite ought to be, you need to know where in the pass it is, and how it's approaching you, such that you might adjust for the doppler shift. It's very fast, you only get the opportunity a few times a day to get on, a lot of things to manage, and high stakes or you look like an idiot to others. I find it exhilarating.

> I know most satellites are meant for modes other than FM, how practical is it to try working satellites with portable equipment while hiking/camping?
The FM sats have the most traffic, I'd definitely start there because the barrier to entry is so low.
Working portable while hiking/camping is extremely doable. I can basically pack all my equipment in a bag that's the size of an arrow quiver. In practice, I just throw it in my tiny backpack and still have an enormous amount of room to spare.

[Anonymous No.1383681]

>>1383680
>I also know you need to track the satellite orbits and need up to date SLE/Keplerian elements to accurately do so, but how out of date can you go before you start encountering problems?
I've never had a problem, don't worry about this

>Can you ragchew on amateur satellites or are you only supposed to use them for basic contacts?
If you worked one of the SSB sats with less traffic, it's possible that you could ragchew on a satellite but it's frowned upon, it's really meant to just be there to make a short contact, exchange callsign, grid and ask for receipt, and then give time for others to call. Small remarks like, "good to hear ya" are common, but again, it's really not good to push it. Unlike the HF bands where you're sharing frequencies, this is different because there are only a few passes a day and you're sharing the transponder timeslot as well as the pass itself. If it's clear that no one else is on the pass, you can start to talk more freely. This can be seen on Saturday nights on AO-92 when it switches to L/v, only a handful of people are up at that hour and have equipment to work it on 1.2Ghz.

[Anonymous No.1383683]

>>1383677
good question, I don't know, but this paper seems to give some good information
https://www.radioeng.cz/fulltexts/2013/13_04_1202_1210.pdf

>In order to mitigate the GPS multipath efficiently,
>many new approaches have now been presented, and some
>of them have got widely used in GPS receivers. At the
>receiving end, according to the place where the multipath is
>mitigated, the GPS multipath mitigation methods can be
>roughly categorized into two types: the front-end methods
>and the back-end methods. For the first type, the multipaths
>are mitigated at the receiver’s antenna. The techniques
>such as the choke ring antenna [3] and the multi-antenna
>array [4] are typical of this kind. For the second type, the
>multipaths are mitigated by processing on the received
>signal’s ACF in the receiver. Based on the number of the
>correlators used in the receiver, this type can be further
>classified into two kinds [5]: (a) the conventional techniques
>such as the narrow Early-Minus-Late (nEML) estimator
>[6], [7], the Double Delta estimator (∆∆) [8] including
>the High Resolution Correlator (HRC) [9], [10] and the
>Multiple Gate Delay (MGD) estimator [11], [12] and so on;
>(b) the advanced techniques such as the Multipath Estimating
>Delay Lock Loop (MEDLL) technique [5],[13], the
>Fast Iterative Maximum Likelihood Algorithm (FILMA)
>[14], the TKO [15], [16] and so on. For this kind of (b),
>they often use more correlators than those in (a). Besides
>the techniques mentioned above, the post-processing techniques
>are also now becoming an important part of the
>GPS multipath mitigation methods, and these techniques
>include Wavelet Filter (WF) [17], Adaptive Filter (AF) [18]
>and so on.

[Anonymous No.1383687]

>>1383677
what are you trying to pick up

[Anonymous No.1383792]

Some Ham Radio stuff

[Anonymous No.1383813]

>>1383792
Is that a bike seat?

[Anonymous No.1383817]

>>1383792
>>1383813
FFS DeMarcus

[Anonymous No.1383832]

>>1383813
Yes, a Flite Titanium Transalp from the mid nineties. Unused NOS condition.
I'm into cycling since ages.

[Anonymous No.1384101]

>>1383681
>never had a problem
Any other usable real-time sat maps?

[Anonymous No.1384150]

>>1384101
Xephem perhaps? It does a lot but also satellites:
http://www.clearskyinstitute.com/xephem/earthsat.html

[Anonymous No.1384193]

>>1383683
Interesting find. Choke Ring Antennas seem to have the problem of obstructing satellites near the horizon which will degrade HDOP significantly. The rest of the paper seems to be about recovering data by rejecting multi path. It would seem best to avoid the problem as close to the antennas as possible. It is however noticeable that Quadrifiliars were not mentioned.

>>1383687
I was thinking of emitter localisation using multilateration in which case very accurate timing is necessary,

[Anonymous No.1384241]

>>1384101
https://www.n2yo.com/?s=43017|43137|40967|27607

[Anonymous No.1384670]

Something strange is going on with my $15 SDR in the 30MHz range. The waterfall I get seems to change nonlinearly dependant on my centre frequency. For example, pic related shows the same AM signal on each waterfall at a different frequency and surrounded by different frequencies just by moving the SDR's centre frequency from 29.7 to 29.6. A few more tests revealed that the relationship between f_c the centre frequency and f_s the signal frequency was f_s = 89.1 - 2*f_c. Checking I found nothing of note at or around 89.1MHz, though a different signal there was also in AM. I'm guessing this is aliasing or some other A-to-D issue, but I can't wrap my head around it.

I measured the adjacent signals also, though they sound like they could be two versions of the same signal with different distortions. Their equations were f_s = 4*f_c - 88.8 and f_s = 4*f_c - 89.6 respectively, and again there is nothing at those frequencies.

This shifting doesn't happen at higher (100MHz) frequencies, though the FM mode doesn't appear to be functioning properly. Any ideas?

[Anonymous No.1384671]

>>1384670

[Anonymous No.1384707]

I'm out to take my Technician and General in a minute. Cross your fingers for be anons.

[Anonymous No.1384723]

>>1384707
good luck anon!

[Anonymous No.1384794]

>>1384723
Thanks! Everything went better than expected. Wasn't even the youngest taking it today.

[Anonymous No.1384812]

I have an idea for a contest. Try to get a qsl card from a black person in the age range of 20's through 30's

[Anonymous No.1384819]

>>1384812
samefag here, extra points if you can do it QRP

[Anonymous No.1384824]

>>1384794
Congratulations!

What rig are you getting?

[Anonymous No.1384834]

>>1384794
I have this Kenwood for primary and a baofeng uv-5r for backup

[Anonymous No.1384864]

>>1384794
nice. what did you use to study?

[Anonymous No.1385128]

>>1383387
I second this question. Would like a nice police scanner for comfy listening

[Anonymous No.1385230]

>>1384670
Ok I tracked the 29.7MHz down to a copy of some sort of 92.6MHz; the concert FM station. The wide bandwidth should have given it away, but the Vivaldi did instead once I improved my antenna position.

Any idea what's causing this "aliasing"? It appears as if a bunch of FM stations are being downconverted and obscuring a selection of 10m transmissions.

[Anonymous No.1385260]

>>1385230
Harmonics?

[Anonymous No.1385278]

>>1385230
Could be happening in the antenna or some other metal structure.

This sdr gets FM broadcast interference

http://websdr.mwrs.org.au:8901/?tune=7100am

Which is 1/15th of

http://streema.com/radios/play/343

You can hear the audio a bit if you tune off the side and slope detect.

Makes a mess of the 7125khz AM net.

[Anonymous No.1385289]

>>1383397

In the UK to access the DMR networks you have to register with your callsign to be assigned an ID (9 digits with leading zero), sorry bud but you'll need to get your foundation license.

On the plus - you'll be able to transmit, the exam is piss easy it's mostly basic physics I,V,R and a few questions about the limitations of the foundation license - 10W transmit power, only 70cm/2M bands

look up 'foundation license now' and find a link with mc0mnx in it hosted on webs

There is also a book they'll probably have you read through called 'foundation license now' by the RSGB. Better get your license soon senpai, they're changing the requirements at the end of 2018.

[Anonymous No.1385310]

>>1385289
>they're changing the requirements at the end of 2018
Sharp antennas now illegal and should be dumped in specialty roadside bins.

[Anonymous No.1385334]

>>1373629
To follow up, will pic. be possible? What bandwidth can you expect to see in the waterfall?

[Anonymous No.1385647]

>>1385334
>waterfall
Probably won't get one since you'd only see whatever you're tuned to. You'll have already demodulated the signal by the time it enters the phone, so there won't even be a hint of RF left.

I'm a little curious how the circuit works as a receiver though, and I don't think that mic-input will be doing much.

[Anonymous No.1385673]

>>1385647
It's a direct conversion receiver, original circuit at >>1373629. Q1 is the local oscillator and Q2 is the mixer. Audio output on the emitter.

[Anonymous No.1385829]

How do you tell the difference between SSB and AM when looking at a saved waterfall rather than listening? I'm monitoring CB radio activity so I have the advantage of what I'm monitoring being channelized, however I'm at a loss for how to tell what's actually SSB and what's just a weak signal from someone's poorly aligned radio that's transmitting slightly above or below the frequency it's supposed to be on.

[Anonymous No.1385830]

>>1385829
AM should have a distinct carrier visible.

[Anonymous No.1385843]

>>1385830
I can see the carrier on stronger signals, but it's not as clear on the weaker signals. Should I try increasing the resolution of my recording of the waterfall? Currently it's at 1 pixel = 250 Hz, should I be opting for something like 1 pixel = 100 Hz instead?

[Anonymous No.1385896]

You should be able to receive AM in SSB mode if you get the tuning right anyhow so listen and tune accordingly.

[Anonymous No.1385918]

>>1385829
AM tends to be visibly symmetric, SSB is not.

[Anonymous No.1385920]

When a diesel train goes past my window I get noise in my ears, but when an electric train goes by I get noise in my reception. Any way to filter out that awful commutation noise?

[Anonymous No.1385928]

>>1385920
No easy solution here, just a lot of work:
- good grounding
- directional antenna
- narrow filters

[Anonymous No.1385931]

>>1385928
I guess I'll get around to the first two when I make a proper antenna, but I think my grounding is sufficient.

[Anonymous No.1385952]

>>1385928
Phase cancellation can work if done right.

Google: amateur radio phase noise cancelling

[Anonymous No.1386264]

>>1385647
>I'm a little curious how the circuit works as a receiver though, and I don't think that mic-input will be doing much.
I uploaded a new sub directory on the FTP site: ./ham
ftp://collectivecomputers.org:21212/Books/Cyberpunk/Tech/Radio/ham/
In that directory is the file "NCRC_PixieOperation.pdf" which explains how it works.

[Anonymous No.1386281]

>>1385289
Thanks, I have a copy of that book lying around somewhere.

Just need to find a club where I could practice/take the exam. I'm quite interested in doing an accelerated course, I'd be looking at London Hackspace as they've done something like that before.

[Anonymous No.1386429]

>It takes $5 to apply for your ham licence here
Why do more people have a driver's licence?

[Anonymous No.1386505]

>>1385843
>>1385918
I tried increasing the resolution and this is now clearly visible. I really need to see what CB activity is like outside of the city I live in since lots of truckers are always coming through here. Looking at the waterfall plot from 1 PM to 6 PM today, I think CB channel 38 LSB may actually be more active here than all 2 meter and 70 cm repeaters combined.

[Anonymous No.1386517]

>>1386429
It's $15 to take the test in the US. Although the NCVECs are agreeing to a new fee next year. Probably $20.

>FYI IF YOU HAVE BEEN STUDYING FOR YOUR TECHNICIAN IN THE US, THE QUESTION POOL IS CHANGING SOON: THE OLD POOL IS BEING DISCARDED FOR A NEW ONE VERY SOON:

New Technician class (Element 2) pool will take effect on July 1, 2018.
Important Reminder: Basic Qualification Question on New 605 Forms.
Exam Maker Software - Unavailable.
Resources for ARRL VEs.


========================================================================


NEW Technician class (Element 2) pool will take effect on July 1, 2018 will be valid until June 30, 2022.

On July 1, 2018 a new Element 2 Technician class question pool will take effect for examinations. VECs and VEs will have new test designs available for use at exam sessions effective that date.

The newly revised pool released in January 2018 (updated and re-released February 12, 2018) by the Question Pool Committee (QPC) of the National Conference of Volunteer Examiner Coordinators (NCVEC) must be in use starting July 1. There are three graphics required for this pool and 423 questions in this pool, down slightly from 426 in the previous pool.

ARRL VEC will be supplying all its (near 1,000) Field Stocked VE teams with new test booklets about the 3rd week in June.
Do not destroy the 2014 versions of the Technician exams until June 30!
With the Technician class exam questions changing July 1, new test designs must be used effective that day. Previous ARRL VEC supplied Technician class exam booklet versions (2014 series) and computer-generated Technician class exams created from the 2014 question pool are only valid until midnight June 30, 2018. At that time VE Team leaders should destroy or throw away the old versions of the Technician exams (do not return them to VEC). To avoid a mix-up at the session, do not save old exam versions!

[Anonymous No.1386641]

>>1386429
Oh but it's another 95 to get your callsign and certificate.

[Anonymous No.1386984]

>>1386264
Thank you. There's also the schematics of the Frog (2 crystals), a modern direct conversion transceiver called QXC (pic) and more interesting stuff like the antenna series by W8JHD (antennabook.pdf).

[Anonymous No.1386999]

>>1386984
>There's also
Yes. I have a large library on my computer and increase it all the time. When relevant I dump what I have on that FTP site hoping more people will enjoy this.

I aim to avoid questionable documents to avoid the site being shut down.

[Anonymous No.1387036]

>>1386999
>I have a large library
If you happen to have anything about VHF/UHF turnstile antennas maybe you can upload it and I will find it. Thanks.

[Anonymous No.1387145]

>>1387036
you trying to listen to satellites?

[Anonymous No.1387407]

My SDR has better signal to noise when the antenna plug is unplugged and held a cm or so away from the dongle's antenna socket. I lose 30-40dB on both the noise and the signal, but for whatever reason it sounds clearer without than with.

[Anonymous No.1387410]

>>1387407
Then again this makes sense since I'm using a short monopole indoors. Electric field noise and all that, though I swear the relative amplitudes of the electric and magnetic fields are kept constant a la Maxwell's equations.

[Anonymous No.1387502]

>>1385952
This example just in:
https://www.rtl-sdr.com/demonstrating-two-channel-coherent-spatial-filtering-in-a-gnu-radio-simulation/

[Anonymous No.1387572]

>>1387036
>anything about VHF/UHF turnstile antennas
Sorry, not much there (yet), my main interest is in HF, for historical reasons. However your question tickles vague memories of an alternative that should still work...

Checking on https://www.rtl-sdr.com/?s=turnstile
gave me this: https://www.rtl-sdr.com/simple-noaameteor-weather-satellite-antenna-137-mhz-v-dipole/

That might be a simple but still well working alternative.

[Anonymous No.1387625]

>>1387410
If you had an outdoor antenna that should change.

[Anonymous No.1387679]

>>1369535
>And do you mean that two wires just sitting next to each other in open air have effectively infinite resistance in DC (I know they do) but some amount of capacitance in AC
You've just described a capacitor. Yes, that is why they work as high pass filters.

[Anonymous No.1387900]

>>1369535
>>1387679
I'd suggest to read
https://www.allaboutcircuits.com/textbook/alternating-current/chpt-14/characteristic-impedance/

[Anonymous No.1387953]

>buy one of those "FM microphone" kits for shits and giggles
>turn it on
>look at waterfall
>it's fucking disgusting
I don't know what I expected for a single transistor job. Suppose I'll test it's range next.

[Anonymous No.1387958]

>>1387953
pic of waterfall ?

[Anonymous No.1387973]

>>1387958
Before on top, after on the bottom.

[Anonymous No.1387975]

>>1387973
I can't determine any fm in the waterfall or spectrum. What frequency is it broadcasting ?

[Anonymous No.1387982]

>>1387975
It's those shitty moving red lines in the lower spectrum. Since I was being quiet the mic wasn't picking up any sound so it was just broadcasting the carrier. Clapping makes bands a couple of MHz quake, though that is with my antenna a yard away from the thing.

[Anonymous No.1388103]

Radio noob here. I might be going to live on a farm in a third-world country for a while. I have programming experience so I thought it might be fun to bring a software-defined radio. What's a good SDR and what are some things I can do with it that I wouldn't be able to do in the USA?

[Anonymous No.1388112]

>>1388103
If it's radio spectrum listening, there's nothing illegal about that in the US. If they transmit, you can legally receive it all, even if it's encrypted and you break the encryption.

[Anonymous No.1388128]

>>1388112
I'm going to be on the order of 30 miles away from my current USA home, what kind of setup would I need to transfer data back and forth? This farm (country in general) doesn't have great internet availability, would I be able to transmit data packets via radio?

[Anonymous No.1388133]

>>1388128
Only if you're licensed to do so in that country or they have reciprocity with the US and you can use your American license there.

Otherwise, I'm not allowed to assist your question.

[Anonymous No.1388177]

>>1388128
In the south they use an abandoned geostationary fleetcom sat to stay in contact. http://www.qsl.net/py4zbz/ec/ec.htm has the story.

[Anonymous No.1388221]

>>1388177
DId some guy really take over an abandoned military satellite to broadcast family photos? How does this work?

[Anonymous No.1388228]

>>1388221
SSTV, slow scan tv.

[Anonymous No.1388239]

>>1388177
Love letter in CW is funny.

[Anonymous No.1388917]

>>1388239
Gringos not amused
https://www.solarix.net/us-military-warning-to-pirates-on-260-625/

[Anonymous No.1388957]

>>1388917
>Brazilian satcom pirates
>They gave message in English and Spanish
>Spanish
fucking americans

[Anonymous No.1388994]

Anyone hearing anything good tonight? I can't find shit.

[Anonymous No.1389025]

>>1376560
Ahh, I just found out that even though I'm in the middle of a city we have a microwave link for our internet.

[Anonymous No.1389103]

>>1388957
>burgers announcing shit in both of their languages
i don't see a problem there

[Anonymous No.1389128]

>>1389103
They're announcing to Brazilians who speak Portuguese, not Spanish.

[Anonymous No.1389160]

>>1388917
Russian dual-use satcom experimenters
solarix.net/262-275-russian-satcom-pirates/
Explore the solarix tag cloud for more
Image: mattblaze.org/misc/uhf-sats/spectrum.html
Portable satcom station that fits in a Pelican case
Link to parent page at the top

[Anonymous No.1389411]

>>1384824
>Congratulations!
>What rig are you getting?
Thanks! I haven't done much research on what to get yet. Truth is, I got into ham after buying a pair of UV-5R for my bug out bag (I live near San Francisco and the quake in January bothered me enough to build one). After I started reading about radio in general and licensing and all I fell down the ham rabbit hole. I never had much to do with radio and electronics proper, but I had a lot to do with networks and PC technology so I was already kinda half way there.
All I know is that I don't know enough. I also don't want (and can't) spend too much right now either. Quick look on Amazon, AT-6666 or AT-5555N or TH-9800 (if I forgo SSB) would be sort of affordable. But then I realise they're all chinkshit and I'd be better off saving that money for a Yaesu, but that would delay it even more and I still would have a hard time dropping close to $1k on a radio rig. Is there even anything interesting going on 10m these days?
Last thing is I live in a rented apartment so not many options for an antenna. At least it's 3rd floor and there is a patio, but I would need to conceal it somehow because the lease has rules specifically against putting outdoors antennas anywhere.
Sorry for tl;dr and my life's story, I'm happy to hear any advice for my situation though.

>>1384864
Reading a whole lot of random resources and absorbing the basics, but mainly Hamstudy. Not just cramming the cards but actually reading the explanations for each question and the linked resources. I learned most of what I know now that way. Also ARRL mock exams because Hamstudy kept giving me almost same set of questions each time.

[Anonymous No.1389417]

>>1389411
>I also don't want (and can't) spend too much right now either.
A Pixie QRP radio will cost you about 3 USD. It is fixed 7.023 MHz (40 m band) though you can replace the crystal for other frequencies within the same band.

[Anonymous No.1389428]

>>1384707
Were you at the Methodist Church, in the session with the really drunk guy?

[Anonymous No.1389439]

>>1389417
Nice, I'll have a look into them. I can't CW to save my life though.

>>1389428
Nope.

[Anonymous No.1389451]

>>1389439
Ah. I was a VE on Saturday. Was just curious if you were one of the examines at the Charlie Foxtrot.

[Anonymous No.1389467]

>>1380934
You're going to have to play around with waveforms in Matlab/Octave/Jupyter. Going to need to learn some basic sampling theory. Key phrase is "signals and systems"...

[Anonymous No.1389471]

>>1389439
> I can't CW to save my life though.

Those pajeet ubitx radio kits don't look to bad if you are looking for hf ssb on the cheap.

I have heard delivery can be a bit slow on them.

[Anonymous No.1389575]

How do you get started with learning morse? It just seems a little impenetrable, like you know it or you don't. I imagine seeing morse written down is quite different from hearing it too.

[Anonymous No.1389675]

>>1389575
You up for Koch Method? http://www.g4fon.net/CW%20Trainer.htm

Farnsworth method?
http://www.mechanicalpuzzles.org/codepractice/learning.html

I have a tone issue with my ears so Dih and Dah sound the same to me. Farnswoth is therefore better for me.

[Anonymous No.1389713]

>>1389675
That Koch method looks pretty neat, I'll give it a shot once I've got some free time on my hands.

[Anonymous No.1389716]

>>1389417
>A Pixie QRP radio will cost you about 3 USD.
Can you actually do much of anything with one of those though? They only work on one frequency so you have to call CQ rather than try to respond to other people calling CQ and they transmit at less than 1 watt if I remember correctly.

[Anonymous No.1389736]

>>1389716
Well I imagine it wouldn't be too hard to hook one up to a high-gain antenna+amp, but it's really not worth doing. But if you've a broad SDR waterfall for browsing frequencies for CW it may be the cheapest way to go by far, though you wouldn't have to use it as a receiver at all.

[Anonymous No.1389743]

>>1389675
An old guy I know told me when he was a kid the post master would serve customers at the counter and read morse at the same time

[Anonymous No.1389804]

>>1389716
>you have to call CQ
want a pixie channel pileup?

[Anonymous No.1389852]

I'm interested in building my own FLARM receiver with a Raspberry Pi and a rtl dongle.

My current understanding is that the software uploads FLARM data to Open Glider Network and then you view an online map.
Is it possible to setup the software in such a way that I can view aircraft (that are in range of my receiver) on a map on my local machine without having internet access?

[Anonymous No.1389870]

>>1389852
what?

[Anonymous No.1389871]

death to ham radio and this thread.

[Anonymous No.1389880]

>>1389871
Given we passed 310 this thread will have to end soon, perhaps five days or so. It was a good run and a comfy thread.

Might look into getting a Pixie.

[Anonymous No.1389892]

>>1389871
There's just going to be another thread, regardless of how many stale memes you post or bump limits we reach.

[Anonymous No.1389899]

I've been looking at Bob,s take on an AM transmitter.
The power supply and pre amp doubles as a mic, guitar, pre as well.
Plus it's pine board construction, not some smd chink soldered shit.

[Anonymous No.1390033]

>>1389870
Are you familiar with FlightRadar24? Well its very similar to that, but specifically for gliders/light aircraft.

[Anonymous No.1390073]

>>1389716
I have checked with SDR and there is a lot of activity on 7023 kHz.

[Anonymous No.1390138]

>pixie qrp
How fucked am I if I never even managed to properly solder a 3.5mm jack without melting the insulation, burning my fingers and getting a cold joint in the end anyway? $3 is not a lot, or rather $10-15 from what I see, but I still rather get a couple of beers with that than toss it in the bin after a few hours of frustration.

>>1389471
Very interesting, thanks. However, see above.

>over $100
>on the cheap
Eh, I'm still probably better off saving it for a proper brand name rig. Soldering is my fucking nemesis and not for the lack of trying, trust me I've made enough honest attempts over the last 25 years. It's like I have some dyisability when it comes to it.

[Anonymous No.1390162]

>>1390138
It's not as unusual as you think, PVC insulation is pretty prone to melting and making a mess. Things that help are a temperature controlled iron, a little extra flux so you can get a clean joint quickly, a well tinned iron, and clean wires/leads/pins. But soldering on a board you'll have more leeway since the board will sap up some of the heat that would go to frying a component, though this does mean you may have to leave the board for a minute if it gets too toasty. If you don't have flux-core solder, get some or an external flux tube/tub. Any sort works, but I've heard good things about no-clean flux sticks. Leaded/lead-free doesn't make a noticeable difference in my eyes, but you might find one easier than the other.

$2.50 on aliexpress btw.

[Anonymous No.1390177]

>>1390138
Well start practising soldering on some junked board out of discarded junk pile electronic device. Take parts out then put them back.

[Anonymous No.1390254]

>>1390073
Fun fact of the day: transmitting at the Pixie frequency of 7023 kHz requires an Extra class license.

[Anonymous No.1390367]

>>1390162
>>1390177
Gotcha. I'll try the advice. My iron is probably shit, but after getting burned this many times figuratively and literally I never felt like spending on a better one.

>$2.50 on aliexpress btw.
All the cheap ones are 7.023 which is useless to me as a general (see >>1390254). And the kits with multiple crystals are about $15. If I'm spending this much I may as well throw a few more bucks at it and get an assembled kit complete with a crystal saddle for easy replacements and spare myself the disappointment.

[Anonymous No.1390372]

>>1390367
Buy a cheapie and swap the crystal? May not work of course.

[Anonymous No.1390423]

>>1390367
>after getting burned this many times

Cerebral palsy or something like that? If you have a disability see if the local club will help you do stuff. I know around here the hams sometimes help out other guys who can't do stuff for what ever reason. I met a blind ham once.

[Anonymous No.1390510]

>>1390423
Having no flux or insufficient heat is a very easy way to burn yourself. You keep trying to flow two joints together but they won't stick, until the component you're holding imparts a little too much kinetic energy into your hand. Was the same for me before I got a temp-controlled iron and external flux. Even then I still burn myself every five sessions or so.

>I met a blind ham once
I'd say it's one of the few in-depth hobbies they can get completely involved with, there's really nothing about the analog stuff that needs sight at all, if you're listening and speaking.

[Anonymous No.1390520]

>>1390372
Why shouldn't it work?

[Anonymous No.1390592]

>>1390520
..sockets for the crystal and final transistor, two additional crystals (7.030 and 7.040)..
http://wb4son.com/wpblog/?s=pixie

[Anonymous No.1390610]

>>1390592
>http://wb4son.com/wpblog/?s=pixie
Good find. Replacing the filter seems like a good investment.

[Anonymous No.1390898]

>>1390520
Well I doubt a 32kHz crystal would work, same for a 50MHz crystal (if they even make those).

[Anonymous No.1390931]

>it's after 5 PM
>weather adversary issued
>hail coming down for a little while now
>no amateur radio weather net
There's always been one in the past, I hope that doesn't mean this is dying where I live as well.

[Anonymous No.1391009]

What's the situation with digital voice modes like DMR? After hearing claims that most radios can't be programmed without a separate computer, I realized I have no clue as to what the situation is for setting up radios to transmit with digital voice modes and would like to know more about them. In particular:
>is programming a radio to transmit on digital modes really not possible without a computer for most radios these days, or has that changed over the past couple years
>can you get the information needed to program the radio (talk group and other code plug data) from listening like you can with PL tones on normal analog FM, or is it necessary to get this information by asking someone else/using the internet
>if a computer is necessary to program the radio, is FOSS software available or are you just stuck with the manufacturer's closed source software on the OSes that the manufacturer wants to support

[Anonymous No.1391030]

>>1385230
Maybe try reducing AGC? Strong local signals may already be on the verge of swamping your sdr.

[Anonymous No.1391034]

>>1391030
I'm unsure how the AGC works for FM, but I find I'm getting better signal-to-noise with a smaller/no antenna, which would confirm the theory that my SDR is getting swamped with too-high amplitudes. I'll try adding some sort of attenuator in series with my antenna to see if that helps. I'll put a potentiometer in there with one side to ground and the other to the antenna, with the centre to the SDR. Any idea what resistance I should use? I'm guessing logarithmic would be better.

[Anonymous No.1391041]

>>1391034
>Any idea what resistance I should use?
Not a clue. I'm not actually a ham, just an interested nerd, who got interested through building tesla coils. You're basically responding to a caveman. I wish you luck though!

[Anonymous No.1391122]

>>1391041
>I'm not actually a ham, just an interested nerd
Makes two of us.

[Anonymous No.1391152]

>>1391122
There are a few of us. I've worked with RF to about 30kw but not actually a ham.

[Anonymous No.1391169]

Anyone know what a ham licence is like on a CV?

[Anonymous No.1391170]

>>1391169
I think I used mine back in the day when I had little in the way of academic qualifications. It didn't help much but might be useful in distinguishing you from otherwise similar candidates.

[Anonymous No.1391177]

>>1390898
I was more thinking about another frequency within that 40 m band.

[Anonymous No.1391182]

>>1391009
Well, on further looking it seems that most all DMR radios aren't front panel programmable. Not entirely sure about the others yet.

[Anonymous No.1391191]

>>1391182
What kind of programming do you wish to do? Frequency lists? Or new codecs?

[Anonymous No.1391197]

>>1391041
Looks like using anything under 10Ω will turn into some variety of filter at FM frequencies, guess I'll have to buy another pot.

[Anonymous No.1391201]

Cheap Arduino FPGA board coming:
https://www.electronicsweekly.com/news/products/bus-systems-sbcs/arduino-announced-fpga-board-new-atmega-uno-wi-fi-2018-05/
Could be pretty interesting for ham use. I have pondered using some for goniometer use.

[Anonymous No.1391209]

>>1391034
>what resistance
First attempt 100Ω lin. Connection as you described or alternatively: input (antenna) to slider, ccw end to ground, cw end to output (receiver). Real 50Ω attenuator at www.qsl.net/z33t/rf_step_attenuator_eng.html

[Anonymous No.1391278]

>>1391209
Ah, just read how having an incorrect input impedance would cause some signal to bounce around. I'll make a test network or two and see what works.

[Anonymous No.1391320]

>>1391191
I'd like the ability to program new frequencies for repeaters when traveling.

>Or new codecs?
Is this even possible/needed?

[Anonymous No.1391335]

>>1391320
Sure. The codec just converts between bitstream and audio. And Codec2 is open source. You just need to access the bit stream. Off the shelf radios are unlikely to do this but some have been jailbroken.

[Anonymous No.1391405]

>>1391009
Alright, it seems that Yaesu System Fusion radios can be programmed without a computer and seems to be just substituting digital voice in place of analog voice with no features like TDMA. D-STAR radios also seem to be programmable on the go without a computer, but are rather complex. DMR radios can't be programmed with a few exceptions and are also more complex to program like D-STAR (though D-STAR may be a slight bit more complex). D-STAR/Yaesu System fusion radios seem to be significantly more expensive than DMR radios though (even when considering the cost premium due to the manufacturers that make them), and I think they'd be kind of hard to justify given their lower/more varying popularity. I think it'd be for the best if I avoid investing in something like this right now.

[Anonymous No.1391666]

>>1391405
>avoid investing in something like this
I arrived at the same conclusion.
Too much CONTROL, too much MOTOROLA.
"Don't call CQ - this is not HF"
www.dmruk.net/gettingstarted.htm

[Anonymous No.1391767]

bump

[Anonymous No.1391773]

>>1391767
anon...

[Anonymous No.1391777]

Is this any good? https://chattanooga.craigslist.org/ele/d/two-yaesu-ssb-radios/6596212373.html

[Anonymous No.1391849]

>>1391777
Big if true.

>check local cl
>a couple >$1k rigs in questionable condition
>a hundred baomemes sold for $75 as "police scanners"
kill me

[Anonymous No.1391873]

>>1391849
Well we've got a surprising number of this sort of thing.

[Anonymous No.1392020]

>>1391278
Well I made a 10dB attenuator, it doesn't help at all. I'll see what I can do later.

[Anonymous No.1392030]

New thread >>1392029

New thread >>1392029

New thread >>1392029