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#1
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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_". |
#2
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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 -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#3
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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 |
#5
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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 For email responses, remove "nospam_". |
#6
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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 |
#7
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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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