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Old November 26th 03, 11:25 PM
Space Charge
 
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Default 25 pf Air Variable Cap Sought

Am trying to build the 80M loop at:

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

....and need a 25 pf air variable cap, but don't have one in the shack
parts bin with a high enough voltage breakdown rating/plate spacing.
The author recommends a plate spacing of 2mm (about .07").

Anyone have one they'd care to part with?

Short of that, a US parts source would be great...Jackson makes 'em,
but they're in the UK, and a bit pricey at that.

Thanks to the group,

Lin/KJ6EF
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Old November 27th 03, 04:20 AM
Cecil Moore
 
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Space Charge wrote:
...and need a 25 pf air variable cap, but don't have one in the shack
parts bin with a high enough voltage breakdown rating/plate spacing.
The author recommends a plate spacing of 2mm (about .07").


Fair Radio Sales might have something like that. 419-223-2196
--
73, Cecil http://www.qsl.net/w5dxp



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Old November 27th 03, 08:03 AM
OK1SIP
 
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Hi Lin,
use a relatively common air-spaced AM capacitor, also one with
deformed plates and temporary short-circuits can be used. Rip out two
plates of every three, both from stator and rotor, evenly spaced. This
way the spacing of plates triples.

BR from Ivan OK1SIP
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Old November 27th 03, 08:44 PM
Tarmo Tammaru
 
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I suggest you mark the edges of the plates that you are *not* removing with
paint, or something, to make sure you end up with symmetrical spacing. You
remove pairs of *adjacent* plates.

Tam/WB2TT
"Space Charge" wrote in message
news:3fc658f4.296883@nntp...
Most ingenious. Thank you, Ivan!

On 27 Nov 2003 00:03:20 -0800, (OK1SIP) wrote:

Hi Lin,
use a relatively common air-spaced AM capacitor, also one with
deformed plates and temporary short-circuits can be used. Rip out two
plates of every three, both from stator and rotor, evenly spaced. This
way the spacing of plates triples.

BR from Ivan OK1SIP


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Old November 27th 03, 09:14 PM
Tarmo Tammaru
 
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Don't assume the new capacitor value will be 1/3 of the original. You have
to take into account the thickness of the plates you removed. (I pried them
off with needle nose pliers). The new value might be more like 1/6 of the
original.

Tam/WB2TT


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Old November 27th 03, 11:57 PM
Joe Strain
 
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Hey !

Thanks for the URL...I need such an antenna for SWL

I dont need the rigid-specification capacitor you do, since I'm not
transmitting.

Accordingly I can get a 25 pf variable at Skycraft for a couple bucks but
their plate spaceing is half your specifications.

Yodar in O'do

==============================
"Space Charge" wrote in message
news:3fc53490.29195260@nntp...
Am trying to build the 80M loop at:

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

...and need a 25 pf air variable cap, but don't have one in the shack
parts bin with a high enough voltage breakdown rating/plate spacing.
The author recommends a plate spacing of 2mm (about .07").

Anyone have one they'd care to part with?

Short of that, a US parts source would be great...Jackson makes 'em,
but they're in the UK, and a bit pricey at that.

Thanks to the group,

Lin/KJ6EF
For email responses, remove "nospam_".


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