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HT's are as close to having an isotropic antenna as anything to be had.
Dave WD9BDZ Dave Platt wrote: In article , Dave Bushong wrote: You missed my point, I think. The counterpoise is the (poor) metal of the radio and of the user's hand. Any connector/adapter will be coaxial and probably low loss, but the counterpoise stays put. The feedpoint rises but the "ground" plane does not. For an SMA adapter, it might not be enough to hear a difference, but the radiated signal will be worse when using such an adapter. I'd say "may be worse" rather than "will be worse". In some cases, it may be better. From what I've seen (and measured) the actual impedances, "counterpoise" effectiveness, etc. of HT antenna setups vary all over the map, and change constantly depending on a whole bunch of factors... how you grip the HT, whether you happen to be wearing a glove, how you angle the HT near your head (antenna-loading effects from the head can make SWR change dramatically), and probably whether you're sweating or not. A typical HT case is almost certainly _not_ serving as a tuned counterpoise at 2 meters, nor is your arm and body. Adding a centimeter or three of SMA-to-BNC connector to the length of the "counterpoise" may have some small effect in some cases, but I believe that [1] it's as likely to work for you as against you, and [2] it's probably less than the sorts of impedance variations which a typical HT has to face every day as it's moved around the user's head during transmission. |
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