The Best Two Antennas I Have Ever Had

For all low bands, 160-30M, my own designed “Modified Bobtail” is a very clear winner. I’ve blogged extensively about this antenna, and the best antenna tuner for this antenna – and my favorite antenna tuner of all time is the Palstar BT1500A. Every feature, knob and button is useful and perfect for the Mod Bob. The best yagi antenna I have ever had was…

Final Notes on the U.RAT

I installed the URAT out back at the base of the “Mod Bob” antenna. I experimented for a few hours and I was able to get a decent SWR on 160, 80, 40 and 30 by doing this: 160M – bypass the capacitors and use a shunt coil at the antenna feed 80M – use the capacitors with that same shunt coil 40M – same…

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…

The S and Z Match for the URAT

I was going to disassemble the u.RAT and re-use the components, but I have just come into a second variable capacitor – which is the Palstar C600, a true work of art. I am trying to get rid of having a roller inductor in the circuit, but would much rather have a switched inductor. Yesterday I posted this circuit: And the Palstar BT1500A has…

Collins 32-V3 Antenna Tuner Circuit

I stumbled on a suggestion for a balanced tuner circuit that is suggested in an old Collins 32-V3 transmitter manual. The top circuit is one that I am most interested in. I’d love to try it and compare it to the Palstar BT1500A – which works perfectly, but it would be super if I could use the URAT with two variable capacitors and a…

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…

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:    

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  practical 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….

The Best Antenna Coupling Presentation by W0QE

Excerpt from Palstar BT1500A balanced antenna coupler. I did a few Google searches for “LC Antenna Tuner” and found the best presentation on the topic yet: http://www.w0qe.com/Papers/Antenna_Tuners.pdf It is just packed with so much useful information – and it covers the topic at a level that reminds me that I still have a lot to learn. In fact, it pulls everything that I have been thinking…