brainwagon

Okay, I got about half of the Plan 13 code ported to C++. It’s a fresh port of the original BASIC code, but modularized into objects better, and with a few bits of tidiness that C++ provides over basic. I estimate another hour or so to finish the code, if I work carefully and efficiently. […]

Well, tonight I had some mild success! My Gameduino satellite tracker is up and running! It’s not got much in the way of a user interface, but it here you see the ISS position marked with a purple/magenta dot, and then dots showing the position of the ISS every three minutes for the next two […]

This article was linked from hackaday, and seems very, very cool. Sure, GPS receivers are cheap, but building one is cool. I am not likely to be doing a project like this, but it’s cool to read about. Homemade GPS Receiver.

My face is red. I had claimed yesterday that nobody had tried to decode my SSTV challenge, when in fact both Ken and Eric decoded it. Eric was the first, who sent me this decode: It’s a bit noisy, because he just played the sound file on his laptop and decoded it on a PC […]

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 […]

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 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 […]

I’ve been trying to get out and record more ARISSAT-1 passes, in the hopes of getting some nice SSTV images. If you follow @brainwagon on twitter, you are likely to see some of the more mundane images that I’ve been getting thusfar. I keep hoping to snag some truly great ones, but thus far, the […]