/hamradio/ - Electronics

>>990

Perfect!

>>1187

There's no mainstream technique that I'm aware of (beyond some speculative stuff associated with 5G cellular, and that seems to be fun and games with polarization that's only viable at SHF over short distances) that lets multiple stations transmit on the same frequency at the same time and simultaneously receive every other station.

Most existing techniques for doing this rely on some central facility that receives individual transmissions on diverse channels, mixes them, and then provides a single downlink stream. It's easy to imagine a system for doing this "over the air" via TDMA and/or FDMA, which is most likely what the Cardo system is doing, but those systems all have fundamental limitations when it comes to the number of users and the system topology.

There's not usually much amateur or professional radio interest in this technology for medium or large scale applications, because human beings can only reliably hear one person at a time.

Get on 6666kHz and 10420kHz and cheeki breeki with the surviving ruskies. Maybe with some 3400kHz AM thrown in and 3900kHz EC thrown in.

Everybody radios will be dead from EMP, except those who have vacuum tube (valve) radios. But then no one will have the power to run one. And who will listen?

>>1076

The dreaded emp is still just the same kind of electromagnetic radiation your radio was designed to detect. Just too much of it. Keep your antenna and power connectors capped off and/or put your radio in an ammo can.

Most military radios today are tested to withstand a typical nuclear EMP. It’s not a death ray that will wipe out everything electrical.

>>1092

On the bright side, it'll sure clean up the airwaves.

>>1076

Yeah, no.

Channel 1 on FM PMR446

>>1081

Tried adding more capacitance in parallel to the variable cap to push the resonance down?

Ould be just a piee of RG58 (QRP) or RG213 (100W and down).

>>1120

I did build a resistive VSWR meter as a new ham. Ony had a dual band HT and no money, so I made my own.

Used the "homo ludens electronicus" resistive bridge design.

>>1181

>Tried adding more capacitance in parallel to the variable cap to push the resonance down?

Yep, I got around to trying out ~30cm/30pF of RG213, but didn't achieve much.. That antenna is kinda retired now that I've made up dipoles with neato kevlar-core copper(braided) wire.

>>1166

Was going to replace it with something..

"your mom lets you eat two baofengs" actually sounds funny now.

>>1168

Radios need antennas, you fucking Technicians.

>>1163

>Gee Bill! How come your mom lets you eat you baofengs?

Eating? These are going up my ass.

>>962

>>968

The cheaper transceivers' frequency starts crawling when you have a slightly longer QSO, and the rigs have shit RF protection. Also, the cheaper the rig is, the more spurious emissions they transmit, usually. And the manufacturers often claim that their cheap rigs have some BS marketing features, like a hand-held that has ~10 W of TX PWR. The Wouxun/baofeng UV5R and baofeng UV-82 are pretty much the only good cheap transceivers. If you want to get a HF/Multi-band rig, you should buy a second-hand one.

>>1139

Ha– moments after posting, a video of that appeared on YT.

…unfortunately, it stops half-way through the questions (when a CCARC guy came in and announced the winner of the door prize, and Rowe bitched about the loud noises next door..)

>>1138

>Well for hamband stuff extreme range IS a plus.

Yes, but neither D-STAR nor Fusion are 6.25kHz wide. That line was directed at NXDN anyway.

>Then build the systems?

I'd love to, anon, but radios are too expensive for me to embrace my inner NEET and work on something like that full time.

>>1140

Now with more FreeDV 2020 on-air demo

>>1133

Yep, especially when they (the japs) have a 1500MHz TDMA trunked network (weird system distantly related to MIRS/iDEN).

Australia is ditching their public safety TETRA and replacing it with P25 Phase2 system from Motorola.

>>1143

MMDVM can use old mobile radio that FSK well or ham rigs with 9600baud packet port (flat audio).

Just building that for some garage DMR or P25 repeater can be a starting oint for experiments and later testing on ading freeDV.

And peole have stuffed 2400A thru annalog HT's.

But yeah I can understand that there's never enough time to work on something like this.

But even a bad kludge with some documentation might inspire others to continue the work.

>>1086

imo, having a license exam is only a good thing but there should be only 1 or 2 license "tiers" or "types". Having a small barrier to entry is pretty much required because what >>1087 and >>1088 said. Also, passing the exam and getting the license proofs that you have at least some technical knowledge and you know how to operate your rig and know the standard parlance and terms.

Anyone try out cnranger?

>>1130

Sounds fun, but unfortunately I'm not my own WISP, and I don't think it's going to be readily adaptable to HAM bands.

>>1129

Yeah microwave's is where it stuff starts to literaly become plumbing instead of traditional electronics.

It would be, because the frequency bands are re-used on new satellites and thus you would interfere with them.

In general just transmitting on those bands, even unsuccesfully would be illegal.

And if you want to pirate voice coms, there are better thargets like the 255MHz US Navy milsats. And more or less all the TV satellites have some unused transponder capacity at the edges.

Just be aware that pirating satellites IS posecuted in usa an milsat pirats have gotten rather large fines.

Most pirates for those systems are in brazil and russia.

>>1111 (reluctantly checked)

These Satellite frequencies ARE available on a technician's license.

but why do they retire working hardware?

>>1141

Because they now have hardware which sends more data over the same (frequency) bandwidth. Why continue to transmit 1 megabit/s when you could transmit 100 megabit/s for only twice the price?

>>1123

Hamband stuff yes.

ANd the ulink to the ryskiye Meridian UHF transponder <;)

>>1141

They usually don't. But you have th have enough fuel to push it to the graveyard orbit. You dont want it drifting there in that orbital slot for eternity when it dies, as GEO slots are very sought afther, and if you eave it there you'll never get launch or frequency permits for new sats.

The new sats usually have more power, more band width and more sensitive receivers.

So you get better SNR, more stuff via it and the end users can use smaller antennas or get more reliable service.

>>1154

Watch the video Hamchad. That external 10 MHz calibration can only be done from the menu (..and then starts drifting immediately). It doesn't lock to a continual reference signal like most rigs of that price band would do (IC-7610..)

The guy I know who bought this lemon has gone back to using his FT-818 (1/4 the price..) and the drift there is only very rarely worse than 1Hz.

>>1155

I did watch the video. They didn't explicitly mention why they weren't using the 10 MHz reference input to lock the local oscillator, only made vague allusions to the IC-9700 "not able to be GPS locked". Given the nature of most appliance operators, that could mean almost anything.

You have to dig quite a bit to find that the "10 MHz Reference Input" on the back panel is only used for the self-cal feature, and doesn't actually lock the local oscillator. Icom doesn't even mention that in either of their transceiver operator's manuals, which is a bitch move on their part.

I could understand doing that on an HF rig, where manual tuning is expected, but it's fucking ludicrous on an exclusively VHF/UHF unit that's being sold as the best on the market.

If not afraid to void the warranty:

They can use a GPS disciplined crystal oscillator,

Have more thermal mass around the reference crystal,

Build a crystal oven for the reference crystal

>>1157

The thermal insulation tricks were tried, as well as a mod to the fan. Didn't improve things much.

This guy <http://www.cortexrf.com.au/IC9700lock.html> has succeeded hacking external GPS locking directly to the internal oscillator.

>>1158

Place one np0 capacitor as a thermal buffer on each pad. Dead bug style with legs sticking up.

The capacitance will probably lower the frequency.

Have the crystal inside a crystal oven at a stable temperature higher than 40Celcious to bring the fre…

Having just typed all the above I googled the board…. Wow, what a small crystal. No wonder it's susceptible to thermal drift. It looks like a pain to get a crystal oven in there too… hmmm

props to the guy who locked the internal oscillator

Solder a beefier crystal in there? Way to save 20 cents I-COM

>>1135

What does one call that ride?

The duke of health hazard?

>>1136

Proof that the owner is… on the spectrum.

Here's a list of GNURadio examples for sending digital files and messages. I believe you can use an audio sink instead of software radio if you want to use conventional transceivers. You should be able to use hackrf in place of usrp, but you'll need an amplifier if you want to transmit beyond your neighbors.

https://github.com/gnuradio/gnuradio/tree/master/gr-digital/examples/packet

>>779

Small/no images.

If/when we get our hamnet thing running It's likely going to feature YaCy distributed search engine, Asterisk/SIP, repeater linking, a wiki, some nostalgic fuck is gona host a BBS and I'm gona stuff up an imageboard.

Pskmail works for basic jobs, no video and slow data files. I used to use it before real internet arrived and while at sea. Its free..

>>835

>pskmail

Fantastic– finally a reason to get off the Novice/Foundation licence. Talking to boring normie strangers is a fucking drag.

https://www.youtube.com/embed/99H6z5rmvco

>>627

with the stucco-foam house I'd say they live in southern california, a shitty place that is wtf as it is.

>>629

Except my lad, natural selection does not really work in the modern world. We've got bright scientists who die without reproducing, and 70IQ Africans having 6-9 offspring.

>>1118

Evolution gives zero fucks about living in space stations– it's all about staying ahead in the race with the microbes.

you know, for some odd reason, with my radio, I've never been able to pick up anyone on 14.313, are the signals too weak for my portable antenna? or do I just have bad timing?

but when listening to 27.025 however, I get plenty of chaos there, particularly around 0200 onwards.

>>631

I go on 27.025 and I just hear weird beeps

>>558

What a bunch of faggots.

>hurr these guys say MEAN THINGS they should go to JAIL REEEEEEEEEEEEEEEEE

>>635

THE NUMBERS

>>635

>I go on 27.025 and I just hear weird beeps

Thats cb CH6 aka Da Bowl.

Mostly just redecks and dindu's running dirty 1-10KW amps yelling over each other on AM.

>>1098

holy shit, that's nuts.

The closet I got is an old dude in a nursing home. cool guy, rambles a lot but never heard anything terribly crazy or odd about him. just that he was old as hell (sounds like 80s/90s).