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Radio Man wrote:
Mark...Can you be specific on what type and/or impeadance of the transformer you are using? Also what antennas are you using it on? I mostly use 9:1 impedance matching transformers I wound myself according to the directions on CW's web site. http://www.kc7nod.20m.com/new_page_1.htm On antennas: #1 is out at the moment because of a lightning strike a few weeks ago and I've been too busy to get it replaced - but it was a 65' random wire made with #14 wire that's 225 feet away from my house (and farther from the neighbors) The coax is underground. It gets practically no RFI. I'm sure it would work almost as well if it was 60-70 feet away from the house, but I don't have tall sturdy trees there. Here's a web site with a discussion of this type of antenna. http://www.anarc.org/naswa/badx/antennas/low-noise_antenna.html #2 is a triangular horizontal loop antenna that's partially over the house. It was made with about 150 feet of #14 wire. Loops are low noise designs, but my house is filled with gizmos that cause rfi, so it's not my favorite. It has a 4:1 impedance matching transformer. #3 was my first antenna at the house - it's 40 feet of wire stapled to the rafters in my attic. It's closer to the RFI and I haven't used it in years. 9:1 transformer. #4 is my current camping and vacation antenna. It's a 3 meter folding whip originally intended for a PRC-25 or PRC-77 with a 9:1 impedance matching transformer that mounts onto a photographic tripod. It works quite well. #5 is an Electro-Metrics ALR-25 Loop. I still need to create a control box to switch bands on it electrically, but ultimately, this may become the "portable" antenna for places I can drive to where I need to use an indoor antenna. This has it's own impedance matching circuitry built in. I have some extra #43 ferrite's on hand that are a little smaller than the one CW's design calls for. They work well. If you'd like one, you can have it for the price of a small padded mailing bag and a couple of stamps. Contact me directly for details. |
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