Field Strength Meter

I’m going to use this new old stock Simpson panel meter for a field strength meter. I’m thinking of making it Arduino or Raspberry Pi based so it can be made wireless – have the sensing circuit out in the yard and it sends data and have the meter in the shack. Kind of a weird digital – analog mash up. There are many…

U.RAT Version 2.0 and Experiments

The u.RAT that I will set up tomorrow will replace the Palstar BT1500A, but only as a test – to see if two Palstar C600 variable capacitors plus one inductor will work on 160M. I expect it will work on 160 and 30M, but not sure about 80M. I split the control box and the drivers so that the Raspberry Pi Zero is in…

Balanced Vs. Unbalanced Antenna Matching

I’m going to add the URAT to a 70′ tall wire vertical with 96 buried radials, and this is a classic 80M quarter wavelength vertical. Its an unbalanced feed with an unbalanced antenna. It will require an L matching circuit: I like VE7BPO’s diagram, and I am guessing that I will need to wire the variable capacitor and roller inductor using circuit B, but…

The Best Part About Ham Radio? Learning

I’m very pleasantly surprised that my latest big excitement in Ham Radio and “Making” is reading about the physics of electronics. Its because I am finding this book to be fascinating. When I was at University of Pennsylvania at Lock Haven in the late 70’s, the physics professor needed a full class for an electronics class he wanted to teach. Lock Haven did not…

The Future of DX-ing and DXCC: ROBOTS!

I’ve been grappling with this for a few years, ever since I was involved with fund raising for VK0EK. I don’t think the average DX-er really knows what a big job it is.  The funniest thing about this blog post is that it came about while sipping a very nice Uinta Detour Double IPA and just sitting back and thinking – musing about the…

Measuring The u.RAT With an Oscilloscope

This is a nice little tutorial on how to use a signal generator and oscilloscope to measure the resonance of a tank circuit. Here is the video: https://www.youtube.com/watch?v=G_RCyDdt2rM He doesn’t show a frequency counter, but my Rig Experts AA-30 will act as a frequency counter. Here is a great video on what I might try with the u.RAT:    

Siglent SDG800 Function Generator

I’ve been researching test gear, and it is actually more for my education than anything. For pure digital circuits, the Salaea Logic Analyzer is a good choice, and while I understand it can handle some analog signals, this is where a function generator and oscilloscope comes in. At Circuitlab.com, I can draw a schematic diagram and simulate what it would look like in an…

First Stop on the u.RAT World Tour: EBARC in El Sobrante

I will be giving my first Maker – Ham presentation at the EBARC meeting this Friday: 7:30pm, Friday, August 11th, at the El Sobrante Library on Appian Way This will be my “warm up” for Pacificon, and several Diablo DXers will be on hand    

ARRL Guide to Antenna Tuners

This is a decent book which covers all of the different kinds of commercial – and a few home brewed antenna tuners (couplers). It is a high level book and offers ┬ápractical explanation of why you might choose one model over another and also whether or not you would use an internal or external or tuner in the shack or out at the antenna….

U.RAT Ready for World Domination!

The final part of this u.RAT “science fair project” is wiring the variable capacitor and roller inductor with a 50 ohm dummy load resistor and then attaching the Rig Experts AA-30 so we can see how tuning the components affects SWR and what the L, C and X values are. I have been playing with different “equivalent circuits” and using a 56 ohm as…