brainwagon

A few days ago, I posted a .WAV file for a classic 8s SSTV image and asked if anyone could decode it. Nobody replied (I wasn’t surprised) so I set about writing my own demodulator. Since I’m inherently lazy, here was my idea: generate the complex signal using my previously debugged Hilbert transform code. Then, […]

Well, it wasn’t so much a difficulty with the Hilbert transform as a difficulty with my understanding. But with the help of my good friend Tom, my understanding was soon put right, and I thought it might make an interesting (in other words, horribly boring to anyone but myself) post, and at the very least, […]

I was trying to determine the exact timings for the classic “8 second” black and white SSTV mode. Copthorne MacDonald suggests 15 lines per second, to make 120 lines in 8 seconds. The vertical sync pulse has a duration of 30ms, and the horizontal sync pulse duration is just 5ms. The sync frequency is 1200Hz, […]

I haven’t had much time for actual experimentation, but I have spent some time researching and some more time thinking about how to properly implement and test analog SSTV modulators and demodulators. I haven’t made much actual progress, but I thought I’d document some of the information that I’ve discovered and my current thoughts. First […]

Last night while watching television, I decided to code up an SSTV modulator for the most popular US mode, which is reportedly Scottie 1. I had done most of the heavy lifting when I created a Robot36 encoder a few years ago, so I mostly cribbed the meat out of that code, and modified it […]

My recent playing with SSTV images coming from ARRISSat-1 have made me think a bit more about SSTV. I used two different applications to decode SSTV images (MMSSTV on Windows, and Multiscan on OS X), and got slightly different results in terms of performance from each. This leads me to ask “just what are the […]

Courtesy of a new $1.99 app called Word Foto, I give you:

Some of you may remember that I wrote my own APT satellite decoder. I ran across someone else who did the same: ATPDEC by Thierry Leconte (F4DWV) It has the same basic philosophy as my own crude efforts: hand it a WAV file, and it will find and produce the APT imagery from inside it. […]

I got pointed at this rather large collection of shortwave recordings which are archived on the archive.org website: Shortwave Pirate Radio : Free & Unlicensed Shortwave Radio Stations : Free Download & Streaming : Internet Archive They have many crazy recordings of radio pirates, some of which are pretty dull, but some of which were […]

I was interested in WSPR and visual MEPT oeprations for quite some time. I operated both a beacon and a QRSS aggregator on 30m for a while, but I grew a bit tired of it, and it’s been silent for a year or so. But I haven’t stopped thinking about them. In fact, I’ve had […]

I found this manual to be informative as I continue my quest to making a properly functioning 8080 emulator. I’m learning lots, but still not quite there. This is just bookmarked for future reference. Digital Research CP/M ® Operating System Manual.

I overslept this morning, and woke up a scant 10 minutes before this morning’s good pass of ARISSat-1 was to begin. Still, all I had to do was go out to my car, grab my Arrow, and my HP laptop, and my trusty VX-3R, and I should be able to make it. I started pulling […]

Okay, not 8080 bottles, but 99 bottles of beer anyway… [proof:~/adad] markv% ./adad ::: brainwagon 8080 emulator version 1.0 ::: 637 bytes of code loaded. 99 bottles of beer on the wall, 99 bottles of beer. Take one down, pass it around, 98 bottles of beer on the wall. 98 bottles of beer on the […]

After getting a version of Tiny BASIC running on my emulator, I was scanning around to try to find something else to run. And, of course, when you look, you find all sorts of cool stuff. I happened across this cool page which is an 8080 emulator which is written in Javascript, and runs entirely […]

I’ve made a tiny bit of headway, but also encountered a link which makes me envious of much greater hacking skill. Óscar Toledo did an 8080 emulator that can boot CP/M as part of the 19th International Obfuscated C Code Contest, winning Best of Show. Its brevity is the “soul of wit”. Check it out. […]