It took a lot longer than I expected, but after trying many LC circuit combinations, and I can make the SPE Amplifier happy on 160, 80 and 75M. Trying to add in 40 and 30M were possible, but by adding in more components and thus causing some loss – which is silly since the DX Engineering DV-40-P works much better on 40M and even works “well enough” on 30M.
I was actually able to tune the antenna to 1.0:1 at 1.822 khz and the SPE tuner easily lets me cover the entire 160M CW band, which is where I find my “DX-citement” these days
I’ve never liked 80 or 75M all that much – but if an ATNO is there, I have it covered. Malpelo is the only ATNO where I worked it first on 80M CW, and its just never been much of a strategic band – not even at sunspot minima. A simple retuning and voila!
After measuring the antenna with the AA-30, I found that the Balun Designs 1:1 current choke followed by this circuit:
I also tried the DX Engineering 4:1 balun, and while it had some interesting properties, I feel better with the simple current choke. There was some strange intermittent behavior with the 4:1, so I will skip that. It seemed to result in giving better 80M CW band coverage, but I’m guessing there was some saturation that stressed it too much, because an amplifier fault occurred after a short while sending at full power. Besides, the SPE makes up that difference anyway with its built in ATU. I’ll take safety and stability over lower SWR but instability any day.
The Spiderbeam push-up mast as Inverted L vertical.
The far support for the Inverted L wire, it is 68 feet away and the rest of the antenna wire drops down from that support. Theoretically, I pick up almost 1 dB gain by not using that mast where the antenna used to be an Inverted U. It’s very interesting how the tuning changes between an Inverted L and an Inverted U.
One bit of sad news, a cheapie Chinese 12v / 5v step down unit burned up and took out my Raspberry Pi Zero W, but I have a spare to press into service. Since I am on 160M 99% of the time, I might not even bother. Less is more when you have high power . . .
I’m getting good on air signals, and with just some very slight tuning, I can get 160M down to about 1.06:1 and 75M about 1.5:1.
With just one test message I was picked up quickly from the East Coast to Hawaii – and it looks like with a strong signal.
OK – all of this work seems to have paid off – now – when will I get to 90 DXCC on Top Band?