brainwagon

I was looking up technical information suitable for implementing some of the SSTV modes (Robot 36, given the recent satellite activity). Here’s a paper by JL Barber, N7CXI that gives you what you need to know. Robot36 is particularly fussy: uses an odd color space, Y, R-Y, and B-Y, with the difference channels sent only […]

Big big thanks to Bill Meara of the Soldersmoke blog for calling my attention to the following link. Even bigger thanks to author Paul Verhage, for putting together this huge collection of useful information about balloon launches. My own high altitude balloon launch ideas have stalled a bit, but this book is excellent inspiration. Near […]

During a morning chat, N2MCS mentioned that he was looking at a simple QRP linear amplifier design and gave me the following url: JBOT – An Easy QRP linear amplifier It was designed by Ashar Farhan, VU2ESE, who is perhaps better known as the designer of the rather popular BitX20 rig. The amplifier takes a […]

I haven’t really been monitoring 10m very much, but I’ve been hearing more about activity there, so I tuned up tonight and caught VE7MTY/B coming in pretty darned well. Check out the .mp3 file: VE7MTY/B, received from CM87ux, 2009-06-15, around 8:00PM local

When I first began mucking around with WSPR, I was using my Macbook, and I couldn’t get WSPR to compile properly. As a result, I reverse engineered the format a bit, and wrote my own transmit only beacon. That was a lot of fun, but recently I picked up a little netbook (thanks honey for […]

At the Maker Faire this weekend, I picked up a Waveshield kit for the Arduino. It’s a cute little board with an SD card interface, an I2C DAC, and a little op amp circuit to provide an audio interface. It took me about an hour and a half to solder together (I’m slow, but careful) […]

I haven’t blogged much about my Softrock 40 since I finished its construction. I knew that it basically “worked”, but I was pretty sure that the opposite sideband cancellation was quite poor, and I wasn’t thrilled with the various software options that I had available, so it sat on my dining room table for a […]

I was reminded that the CQ WW WPX contest is coming up this weekend. I’m not much of a contester, but perhaps it would be a good opportunity to get my Softrock receiver for 40m online and to record a few hours of activity as the basis for future DSP experiments. Activity is always high […]

In the last few days, I’ve heard a few stations in countries I hadn’t seen before, like Guatamala, Brazil, and Portugal. Here’s my updated map:

Over the past few days, I finally got a windows box up and running so I could run the official WSPR executable from WSJT. In the short time I’ve been listening, I’ve gotten quite a few spots from stations who haven’t been able to hear me. I made a quick map of all the sites […]

Project Blue Horizons is a group which is attempting an unmanned Trans-Atlantic balloon flight from the United States to Europe. They are estimating a launch around 0:00-3:00 UTC on the 30th of April and they are supposed to be sending telemetry on 40m. You can follow their updates on twitter. This will be PBH-10, you […]

A while go, I posted a link to AA5CK’s website and his use of the iduino as a QRSS keyer. He used a little oscillator/buffer from Nightfire Engineering along with a home brew, single transistor amplifier. So, I ordered two. And built one. At $7, who could resist? It works, but it obviously isn’t very […]

Here are some interesting kits, all designed to use the 1 Wire sensor bus. In theory, the Open Tracker can use these directly. Perhaps the barometric pressure sensor would be useful on my balloon project. Weather : Hobby Boards : Complete 1wire Solutions

Yep, I’m still working on my balloon project, and part of it is still scoping out the flight hardware. I found this library for interfacing a GPS to the Arduino, and it looks like it could be quite useful. TinyGPS « Arduiniana

So, a couple of nights ago, I went ahead and assembled the OpenTracker Plus kit that I had ordered from Argent Data Systems. The kit is dead simple to assemble, taking me only about an hour, and I was going fairly slowly, checking each solder joint fairly thoroughly. The kit only uses through hole components, […]