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#1
September 3rd 08, 07:02 AM
posted to rec.radio.amateur.antenna
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r7 vertical resonates too high
On Wed, 3 Sep 2008 05:33:58 +0100, coyotevergreen
wrote: any ideas? Radials/counterpoise went south. 73's Richard Clark, KB7QHC |
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#2
September 3rd 08, 08:47 AM
posted to rec.radio.amateur.antenna
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r7 vertical resonates too high
"Richard Clark" wrote in message ... On Wed, 3 Sep 2008 05:33:58 +0100, coyotevergreen wrote: any ideas? Radials/counterpoise went south. 73's Richard Clark, KB7QHC ---------- The R7 doesn't use radials or a counterpoise. It is the electrical equivalent of a 1/2 wave antenna on all bands. That was one of the reasons that it was so popular. Like the OP, I tend to agree that the problem is in the black box. There were several articles published on how to restore the black box to original specs. Anyone know of their location? Ed, NM2K |
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#3
September 5th 08, 12:52 PM
posted to rec.radio.amateur.antenna
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r7 vertical resonates too high
Those 5 spokes are a 'capacity hat' loading the bottom half of the 'dipole'.
If the problem is on ONE BAND, I would look at the capacitor assy for that particular band. They are usually the first item to fail. Your R7 has been on borrowed time for a few years. Emil W9NM "Edmund H. Ramm" wrote in message ... In "Ed Cregger" writes: [...] The R7 doesn't use radials or a counterpoise. Yes it does, those 5 spokes are the counterpoise. It is the electrical equivalent of a 1/2 wave antenna on all bands. Lambda 3/8. [...] Like the OP, I tend to agree that the problem is in the black box. There were several articles published on how to restore the black box to original specs. Anyone know of their location? http://www.iol.ie/~bravo/r7_vertical.htm 73, Eddi ._._. -- e-mail: dk3uz AT darc DOT de | AMPRNET: If replying to a Usenet article, please use above e-mail address. Linux/m68k, the best U**x ever to hit an Atari! |
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#4
September 4th 08, 12:37 AM
posted to rec.radio.amateur.antenna
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r7 vertical resonates too high
Richard Clark wrote:
On Wed, 3 Sep 2008 05:33:58 +0100, coyotevergreen wrote: any ideas? Radials/counterpoise went south. 73's Richard Clark, KB7QHC Ill second that, OR, maybe a crudded joint below the point where the traps start ( remove, clean, and coat with something like Noalox), then reassemble. Also, see : http://www.iol.ie/~bravo/r7_vertical.htm and: http://www.telusplanet.net/public/te...craft_trap.htm for info on R-7 repair-- Jim NN7K |
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