That was a cool video. 90's me would have been in awe of it and would have obsessed over replicating it. 😜

It did rekindle my desire to do something similar, but using modern hardware. Specifically, SDR tools.

I've got a couple quality SDR dongles I use quite a bit. I love surfing the airwaves, I find it very relaxing. I've seen several projects where people use SDR to pull down weather sat images. Looks like a lot of fun. 😀

Thanks! You're welcome! ^^

I really liked the tinkering part. The classic etching, the veroboard etc.
It's also pleasent being able to unite two hobbies here, vintage computing and vintage amateur radio.

JV-Fax can still be used today for receiving weather fax or SSTV on shortwave.
It just needs an SSB capable radio. It also has a Sound Blaster driver (sbjvfax7.zip, 3rd party).

Frequencies: German weather service (sea fax) @3855/7880/13882.5 KHz USB, ham radio SSTV @14230 KHz USB

(ISS SSTV pictures from space need PD120 support, which JV-Fax doesn't have yet.
Scotty and Martin modes used on sortwave are supported, though.
WinPix for Windows 3.1x has PD120, but it's tricky to get running.)

Building a very simple hamcomm modem using an 741 op-amp IC is also possible (it's a comparator/data slicer).
I've built quite a few and did some experiments: https://tinyurl.com/mrxa4rcw

They do still work within VMs, if a serial port pass-through is available.

DE-9 USB serial adapters are a small issue, though, because the 741 modems often rely on positive/negative voltages of a real V.24 port.

As a workaround, two 9v batteries can be used in principle to provide the voltage needed for the comparator function.

There are many more programs that work with a simple 741 modem.
HamComm, RadioRaft, PKTMON, GSH-PC. Just to name a few.

TX/RX sample circuit: https://tinyurl.com/yewbtuk3
GSH-PC in action: https://tinyurl.com/ybyhmzr5

Jo22

PS: About the SDRs.. Back in time we've used soundcard for demodulation: SDRadio, DREAM, SAQrx..
They're from the good old days of Windows 98SE and XP.

All it needed was a so-called direct-conversion receiver (DC receiver), a regenerative radio (audion), or any type of radio with an IF output (intermediate frequency output).
In practive, the signal had to be 7 KHz wide or more (say 12 KHz).

If the sampling rate of the soundcard was good, say 192 KHz @24-Bit,
then it was possible to receive VLF signals such as SAQ or time stations directly.
All it needed was an antenna at the audio in port (with some precautions).

Speaking of RTL-SDR dongles for USB, there's GQRX on Linux and Mac OS X (10.6+, port here).
It's easier to use than most of the other SDR applications, I'd say.

Edited. 2x.

It would be fun to get an SDR working on one of my retro computers but those modern units/programs can really take a lot of processing power I think..? can anyone confirm?

Sphere478 wrote on Yesterday, 06:25:

It would be fun to get an SDR working on one of my retro computers but those modern units/programs can really take a lot of processing power I think..? can anyone confirm?

Modern SDR software can indeed be CPU heavy and does require at least somewhat modern hardware.

Though, SDR++ runs great on everything I've tried it on so far. All running Ubuntu. All of it is about 10 years old, give or take.

• Zotac ZBox Nano P Ci320 with a 1.83 GHz quad-core Celeron

• Atomic Pi with a 1.44GHz with a quad-core Intel Atom x5-Z8350

• Intel NUC NUC5PPYB with an 2.4GHz N3700 quad-core Pentium

There are also SDR software options for Raspberry Pi, and they all recommend a Pi 4.

I did run across https://www.sodirasdr.de and thought about seeing what it can do on my Windows 98 machine, just for fun. I just haven't tried it yet to see if I can get it to work with one of my dongles. 😀