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Antenna article
"Jeff Liebermann" wrote in message ... The coil has nothing to do with why some types of 5/8 verticals show little or no gain vs a 1/4 GP, or isotropic. Just a minor note on this issue. If the coil actually did contribute a 1dB power loss, the lost power would need to be either reflected or dissipated by the coil if it's not being radiated as RF. I haven't seen any high VSWR 5/8 wave antennas, so it's not VSWR. I haven't seen the matching coil on my Larsen 5/8 wave antenna, with a 45 watt VHF mobile, become warm. If it was dissipating 4.5 watts, I should be able to see it get quite warm[1]. I pointed an IR thermometer at the coil and transmitted for about 5 minutes. No change. However, I did see a very slight temperature rise from a mercury thermometer taped to the stainless steel antenna rod (which could be attributable to my sloppiness). The test is easily reproduced. Have fun. Just the same type of easy test that can be done with the old saying of 1 db loss per connector. Connectors have a very small loss in them. If they did have the 1 db or even 1/2 of a db loss and you put 100 to 1000 watts through them you could really feel the heat after a short transmission. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com |
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