Living in an HOA area, my constant quest is for a stealthy, multiband, effective antenna. When I arrive at a good one, I plan to install it in the attic. That installation will reduce the everyday setup and teardown of the “backyard” portable antennas. Over the past year, I’ve tried many antennas and my antenna junk box is full of “spare parts.” I added more to the pile yesterday. It actually is a workable antenna, but one that fails to be as good as others, and fails to meet my expectations.
The antenna is an EFHW that I found in an issue of CQ magazine from several years ago. I won’t be more specific, because I don’t want to cast blame. The thing might work very well for someone else. Like all EFHW designs, this one is a transformer and a wire. The transformer is 36:1, the wire about 65 feet (later cut to trim for 20M), and has an RC network about 1/3 of the way along the length.
My test rig for such an antenna is putting it up in an inverted vee form using a 17 foot collapsible mast as the center support. That form sort of mimics the roofline of the house, for when I move it into the attic. Measurements are made with a NanoVNA.
My expectations are for multiband: at least the CW portions of 40M and 20M, others if I can get them, and SWR low enough that I can run the TR-45L transceiver without engaging its tuner. This antenna got me the first part, resonance at 7.040 and 14.040 (blue trace), acceptable impedance, but with SWRs too high for my liking.
There’s another EFHW that does better. We’ll see it shortly…
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