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Old December 18th 03, 02:04 AM
Space Charge
 
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Default 80M Loop Antenna Quandry

Built the loop at:

http://w1.859.telia.com/%7Eu85920178...s/frameant.htm

....but am having some problems with it; mainly, it seems resonant at
3.2-3.4 Mhz, and all "fixes" seem useless, including installing
"spreaders" as the author suggests.

Pics of the finished loop/thing/dog are at:

http://www.moonlightsys.com/misc/

If anyone could take a minute and look at the *^$%^% thing, and see if
anything obvious jumps out at them, I'd appreciate it. Maybe I've
been looking at it too long to see the obvious. sigh

Thanks to the group in advance,

Lin/KJ6EF

[...please note that the variable tuning cap is disconnected in the
pic, as we were trying to get some resonance readings on the loop.
Also, the wire used is #8 Belden stranded/insulated. Frame is sched
40 PVC.]
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Old December 18th 03, 11:14 PM
Mark Keith
 
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(Space Charge) wrote in message news:3fe10872.29137452@nntp...
Built the loop at:

http://w1.859.telia.com/%7Eu85920178...s/frameant.htm

...but am having some problems with it; mainly, it seems resonant at
3.2-3.4 Mhz, and all "fixes" seem useless, including installing
"spreaders" as the author suggests.

Pics of the finished loop/thing/dog are at:

http://www.moonlightsys.com/misc/

If anyone could take a minute and look at the *^$%^% thing, and see if
anything obvious jumps out at them, I'd appreciate it. Maybe I've
been looking at it too long to see the obvious. sigh

Thanks to the group in advance,

Lin/KJ6EF

[...please note that the variable tuning cap is disconnected in the
pic, as we were trying to get some resonance readings on the loop.
Also, the wire used is #8 Belden stranded/insulated. Frame is sched
40 PVC.]


You need to have the cap hooked up. It's part of the circuit. If with
the cap, it's tuning low in the band, you need slightly less turns on
the loop. Might have to take a bit off. Maybe a 1/4-1/2 turn. Hard to
guestimate on that one. Just trim the loop until it's resonant where
you want it with the value cap you have.
MK
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