Concurring with Tom, assuming you have the polarity of the X correct, and there's more.
A short 1/4 wave-ish vertical that shows R=57 in the R+jX expression is a vertical/counterpoise or radial(s) combo that has far too much resistance and is a dead giveaway for a considerably inefficient antenna and may be wasting 3 dB somewhere. A full quarter wave vertical over 60 1/4 wave radials should be showing 32-35 ohms at resonance, e.g. 33+j0. A theoretical 1/4 wave L in free space with lossless conductors should be 12-15 ohms. In the real world over real dirt with an efficient counterpoise, and lacking various possible real-world inefficiencies an L should be something roughly 25 ohms. Mine is 28 ohms on a calm day over dried out dirt. Frankly, if it really is efficient, 57-j130 sounds like a fairly *longer* than 1/4 wave-ish L aerial wire over an FCP without using an isolation transformer. A bad idea for a stack of reasons. Otherwise, there is likely a lot of dielectric material inside the bend of the L adding loss in the R measurement in addition to 32-35 ohms. An efficient L should show lower R yet to be efficient. Mine is 28 ohms, measured with an AIM4170 with a calibrated feedline factored out by the software. An occasional measurement right at the feed is always very close. In your case R = 57 instead of R = 28 probably means that something like 29 ohms of that 57 is recoverable loss for some reason or other. 73, Guy K2AV On Tue, Feb 28, 2017 at 10:05 AM, Tom Boucher <[email protected]> wrote: > Fred, > If your inverted 'L' was a bit less than a quarter wave long, it would have > been capacitive and showing 57-j130 (not plus). In which case you needed a > small inductor to match it to your 50 ohm coax, not a capacitor. > > 73, > Tom G3OLB > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
