The Cranky Sysadmin A world of technology, fun, and ignorant rants.

February 27, 2013

Why Become a Ham?

Filed under: ham radio — Cranky Sysadmin @ 8:21 pm

A friend of mine from Finland discovered the hobby of amateur radio a few days ago. He doesn’t have a license or a rig. As far as I can tell, the hobby just looks interesting to him. That got me thinking about why someone would want to become a ham radio operator.
No, not that kind of ham

February 26, 2013

Arduino Signal Generator Demonstration

Filed under: Arduino,Electronics,ham radio — Cranky Sysadmin @ 8:26 pm

I have a lot of work to do on my arduino DDS signal generator, but it’s good enough to demo. Too bad I’m bad on camera. Once I have this signal generator to the useful stage, I’ll post some details about it.

February 25, 2013

Antenna Analyzer Progress 1

Filed under: Arduino,Electronics,ham radio — Cranky Sysadmin @ 8:21 pm

I spent a fair portion of the weekend testing my new AD9850 DDS modules and attempting to use some bare AVR chips with internal oscillator as cheap arduino. Read past the fold if you’re interested in the progress.
The Fold

February 23, 2013

Two DDS Modules Have Arrived!

Filed under: Arduino,Electronics — Cranky Sysadmin @ 7:57 pm

I ordered two new AD9850 DDS modules from Amazon. They were shipped from China and arrived in about two weeks. For a quick test, I followed the instructions from N8RO. Both modules seem to work. According to my ancient but still seemingly accurate Fluke frequency counter, one module was off by about 100 hz at 10MHz, and the other was off by about 208hz. Each module will output a nice sine wave up to 40 mhz. Above that, the signal gets really small, and the wave form gets wonky looking. Since antenna analyzers need a signal generator, my next step is to breadboard out one with a DDS module, a rotary encoder, an LCD, and some push button switches.

February 21, 2013

First Phase in Building an Antenna Analyzer

Filed under: Electronics,ham radio — Cranky Sysadmin @ 5:02 pm

What I have is probably a case of “Make a problem as hard as possible before solving it”-itis. I’ve been looking up at my G5RV-lite antenna and considering a replacement almost since I bought it. The antenna seems to perform well enough on 20 meters and up, but at 35 feet high, I mostly hear local traffic on lower bands. I’d like to solve that problem by building a new antenna. This leads me to the fact that I would like to measure said antenna. Since I’m looking for solutions for ARRL Field Day, I’d like something more portable than my Atten AT6011 spectrum analyzer.

February 18, 2013

HP HEDS-7501 encoder data

Filed under: Arduino,Electronics — Cranky Sysadmin @ 4:44 pm

I recently tore down some old controller for an X-ray device that I bought at a surplus shop for $15. I couldn’t find a data sheet for this model, so I derived the pinout from the circuit it was in. The pinout and characteristics that I could figure out follow the fold.
the fold

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