This testimony als confirms my earlier message. The TX antenna must be
resonant to re-radiate. The length and the termination of the feed line on
RX, in allmost all cases plays an important role.
TThank you for your testimony, Paul!
73
John, ON4UN
At 17:50 3/5/98 -0700, you wrote:
>I can't comment directly about beverage and transmitting antenna
>interaction, but I have made observations about antenna interactions on my
>urban antenna "garden" that is 120'x120'. My transmitting antenna is a
>bent piece of wire that goes upward from the ground at an angle of about 60
>degrees above the horizontal to a maximum height of 52', then slants back
>towards the ground--included angle between the two segments is about 110
>degrees, and the far end is about 12' above the ground. The ground system
>consists of buried radials, probably about 40 in number and ranging in
>length from 15' to 100', restricted essentially to one quadrant (except for
>the few tht I was able to sneak into the alley behind the house). By trial
>and error I made the total length such that, with an appropriate series
>capacitor (about 170 pf), I get an swr of 1:1 at 1830 mhz. 2:1 swr
>bandwith is from 1805 to 1855 mhz (approximately). Some of you that are
>good at modeling want to tell me how bad my ground system is?
>
>My receiving antennas consist of three 8' diameter and one 12' diameter
>shielded tuned loops--plus one coax bazooka type. If I do not open, with a
>relay, the fed end of the transmitting antenna while receiving, both the
>directivity patterns and S/N ratio of the receiving antennas are grossly
>degraded.
>
>With a Radio Shack portable receiver, tuned to 1830 mhz and in the CW mode,
>held about a foot away from the transmitting antenna, the difference in
>noise picked up by receiver when the fed end of antenna is (a) open or (b)
>connected to the feed system amazed me the first time I tried it. With the
>relay open and noise barely audible, the noise became a loud roar when the
>relay was closed. The difference in noise reradiated by my transmitting
>antenna is significant in the two configurations.
>
>73 Paul W5DM
>
>--
>FAQ on WWW: http://www.contesting.com/topband.html
>Submissions: topband@contesting.com
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>Problems: owner-topband@contesting.com
>
>
***************************************************************
* John Devoldere, ON4UN, AA4OI, OT8T *
* e-mail: john.devoldere@innet.be *
* address: Poelstraat 215 *
* B9820 Merelbele *
* Belgium *
* mailing addres: P.O.Box 41 *
* B9000 Gent, *
* Belgium *
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* *
* PLEASE CALL US IN THE CONTESTS (ON4UN OR OT8T). THANK YOU! *
* *
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FAQ on WWW: http://www.contesting.com/topband.html
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