Ham Radio / Off-grid communication

BIG BILL HELL'S said:
I've built a QDX (works) and a QCX (doesn't work for some reason). I don't really know why everyone complains about winding the toroids, it's fine if you take your time. My problem has been that some of the soldering is really tricky because the pads are so close together.

I recommend printing the instructions out so that you can mark things off as you complete each step.
Click to expand...
I built an mcHF QRP set a few years ago, it is nice and small and works well with a laptop via USB. The PCBs are an easy enough build, fitting it into the case is actually a bit tricky as it’s so tight.

Still seems to be available, as pre built too.


Project source: https://github.com/m0nka/mcHF/
 
888Flux said:
This looks great but I'd be concerned with quality control issues buying one pre-assembled from China. I really like the 10 watts of TX power and internal USB soundcard though.

Do they sell these as kits?
Click to expand...

Well, it’s an open source project and I bought my kit from a ham in Slovakia! It was very nicely prepared, instructions were good, and I got an ATU board for it at the same time.

However their website no longer exists and I can’t find anyone else doing the kit.

If you are keen, I saw this post giving a full and fairly current parts list, and of course ordering the PCBs from JL PCB or similar is quite cheap and easy.


The design and software is pretty mature so I wouldn’t worry too much about it seeming quiet on the development front, that’s just the way these things go.

Another way to go is buy the Chinese made one but go through the test and setup yourself, and adjust the toroids if necessary.
 
Y'all
If we superchat the money do you think we can get null to get his license that way?

Surely we can scrape together enough for a General License, a UV5R, and a digi-rig to get him started! Even he's not too retarded to pass it in a month or two.
 
Ayo what's up greyheads. I am a man under the age of 30 who's interested in talking to boomers with archaic radio technology. What do I need to purchase to start harassing old people in old Soviet countries
 
Platonic Ideal said:
Ayo what's up greyheads. I am a man under the age of 30 who's interested in talking to boomers with archaic radio technology. What do I need to purchase to start harassing old people in old Soviet countries
Click to expand...
Welcome to the club! The OP has a few resources and recommendations to get started. Cheapest way is to get a handheld (or base station for a little extra), get a Technician license (if in the US) by studying for and passing a basic test and then hit your local repeater. That gets you on the air more-or-less locally or regionally. International contacts (barring using EchoLink/Allstar which is basically an internet messaging platform with extra steps) are a bit trickier and more expensive if you want your voice in particular since you'd need to transmit on what's called HF (also explained in the OP real well), but there's still plenty of fun things you can do there even for relatively cheap - this thread has a whole load of cool projects people have done and talked about. There's a shitload of different things you can do. Have fun!
 
Platonic Ideal said:
Ayo what's up greyheads. I am a man under the age of 30 who's interested in talking to boomers with archaic radio technology. What do I need to purchase to start harassing old people in old Soviet countries
Click to expand...
Welcome! You'll want to focus on HF radio stuff, so at least a General License (assuming you're in the US) otherwise, check the OP and if you have further questions feel free to ask!
 
Found this vid today, interesting design for 10/15/20 meter HF dipole using stuff from a hardware store

You could definitely do FT8 with this
 
⚞⛇⚟ said:
Can microwaves in short bursts affect people's health?
Click to expand...

Microwaves are non-ionizing radiation (the bad stuff ionizes) and you’re being bathed in it constantly from radios, WiFi, Bluetooth and the like.

Unless you’re hanging out on top of a military radar installation you’re good. Even if you were it would burn you not give you cancer aids.

Whatever they’re using that causes Havana syndrome is something else.
 
⚞⛇⚟ said:
What do you all think about Havana Syndrome? I feel like the people in this thread would have a better understanding of it than anyone else on this site.
Click to expand...
I'm not sure. There's a lot of hysteria surrounding EM radiation, ranging from stuff about 5G to fanfiction about HAARP. People hear the word "radiation" and go crazy, as it's like a magnet to schizos.

The main risk of non-ionizing radiation are thermal effects because the body is a good conductor, since it's mainly water with a bunch of different ioons. But this requires both extremely close proximity and insane amounts of power.

A lot of the basis for claims that RF radiation is dangerous are based on casual relationships and ill supplied data. The WHO classifies cell phone emissions as possibly carinogenic but the study they did is all bullshit and based on a very small sample size. And the classification was given based on the relationship between cellphone use and acoustic nueroma, and also more preventative than anything.

If "Havana Syndrome" was the result of something electromagnetic I think it would be much more noticeable. You would have visible burns. And there is no way you could hide the signature on the RF spectrum of something like that.

If I had to take a guess it's probably something that operates similar to this: https://en.wikipedia.org/wiki/Long-range_acoustic_device

If you look at the symptoms of "Havana Syndrome" they all correlate to inner ear disturbances. Dizziness, naseua, balance problems, etc. The vestibular system maintains all of that function. And the common denominator in ALL reported cases is a high pitched tone.
1771277711766.png
 
888Flux said:
Dizziness, naseua, balance problems, etc. The vestibular system maintains all of that function. And the common denominator in ALL reported cases is a high pitched tone.
Click to expand...
Infrasound was always something I wondered about. It's a hell of a lot harder to measure accurately since your equipment moves from mics to something closer resembling a seismograph. Ultrasound is surely possible too, but nature is a low-pass filter and it's hard to push ultrasound very far without a shitload of directed energy, so you would want to use proximity to your advantage as an attacker. Very similar to transmitting distance and antennas. The high pitched tone they report could very well be their ears ringing from exhaustion.

The fun part of all this is you can cause these symptoms with just about any tone/frequency if you play it constantly without breaks. Happens to me all the time while doing bass sound design work lol. It's that awful "I wanna get off this ride" sort of feeling.
It's a lot worse if you introduce any weird stereo effects. It makes sense considering a sound being significantly louder in one ear has historically been associated with an annoying insect buzzing in your ear—something that understandably agitated our ancestors. The psychoacoustics of sound localization and spatial hearing has long been an interest of mine, so I could ramble about this for hours.
 
Last edited:
very cool vid (using manim!) on I/Q sampling, this guy has a whole channel for radar maths but also applicable to anything DSP


Juan Números said:
modem73's latest version, everything is still fine, except I'm also receiving all the packets I send.
Click to expand...
There's now a TX blanking option. For full-duplex audio or loopback issues from your rig you can enable that and it will lockout the decoder from receiving your own packets that you send.

Also, there's now a new scope tab with a realtime OFDM constellation diagram that renders in the terminal, example using 8PSK:
 
X6100 armbian image https://github.com/Links2004/x6100-armbian running modem73



1771631685396.png

one of the drawbacks is you have to connect the radio's DEV to HOST port into itself to get access to the RX audio. doing this brings the noise floor up a notch because of the electrical gnomes, but I'm playing with different cable configurations to see if this can be mitigated.

my goal is to make everything self-contained so you only need to bring with you the radio, instead of radio + computer for data operations. it should also be possible with the X6200 https://github.com/tom-acco/Xiegu-X6200-Research
 
888Flux said:
X6100 armbian image https://github.com/Links2004/x6100-armbian running modem73

View attachment 8588811

View attachment 8588809

one of the drawbacks is you have to connect the radio's DEV to HOST port into itself to get access to the RX audio. doing this brings the noise floor up a notch because of the electrical gnomes, but I'm playing with different cable configurations to see if this can be mitigated.

my goal is to make everything self-contained so you only need to bring with you the radio, instead of radio + computer for data operations. it should also be possible with the X6200 https://github.com/tom-acco/Xiegu-X6200-Research
Click to expand...

So this is a ham radio running Raspbian? That’s fucking awesome.
 
888Flux said:
X6100 armbian image https://github.com/Links2004/x6100-armbian running modem73

View attachment 8588811

View attachment 8588809

one of the drawbacks is you have to connect the radio's DEV to HOST port into itself to get access to the RX audio. doing this brings the noise floor up a notch because of the electrical gnomes, but I'm playing with different cable configurations to see if this can be mitigated.

my goal is to make everything self-contained so you only need to bring with you the radio, instead of radio + computer for data operations. it should also be possible with the X6200 https://github.com/tom-acco/Xiegu-X6200-Research
Click to expand...
Really neat to see! It's amazing what the X6100 can provide. I oughta get one of these things sometime and then maybe a 100W amp for it.
I'm starting to look into BBSes myself, especially on HF. Has anybody worked with them before? Not entirely familiar with the scene.
 
Channel Catfish said:
Really neat to see! It's amazing what the X6100 can provide. I oughta get one of these things sometime and then maybe a 100W amp for it.
I'm starting to look into BBSes myself, especially on HF. Has anybody worked with them before? Not entirely familiar with the scene.
Click to expand...
Wait there are BBSs on HF? This is like finding out there is a secret world underneath the earth’s crust
 
You must log in or register to reply here.
Back
Top Bottom