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| To: | [email protected] |
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| Subject: | RE: LF: Antenna tests |
| From: | "Rik Strobbe" <[email protected]> |
| Date: | Fri, 13 Dec 2002 12:01:07 +0100 |
| In-reply-to: | <[email protected]> |
| References: | <[email protected]> |
| Reply-to: | [email protected] |
| Sender: | <[email protected]> |
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Hi Hugh and Gary, If you have a 136kHz TX it's rather easy : measure the antenna current and the TX output voltage, R = U/I. The calculated R is the total loss resistance + radiation resistance, but the last is far less than 1 Ohm so you can ignore it. If you want to know the ground loss (or better said environmental losses) you have to subtract the loss in the loading coil. An more direct resistance measurement can be done using a Wheatstone bridge or something similar ("antenna analyzer"), have a look here for some construction ideas : http://home4.swipnet.se/~w-41522/bridge/bridge.html http://www.lwca.org/library/articles/k0lr/lfanalyz/lfanalyz.htm http://www.lwca.org/library/articles/k0lr/lfanalyz/mfj259.htm http://www.geocities.com/df8zr/zx.html Some interesting reading on ground loss at G3NYK's webpage : http://www.alan.melia.btinternet.co.uk/aelossbr.htm 73, Rik ON7YD At 21:43 12/12/2002 +0000, you wrote: Hi Hugh, |
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