[Elecraft] OT - Source for Air Variable Capacitors

[Dauer, Edward]

Many thanks to all who replied, both on-list and off.  Apparently these things are available even if I couldn't find them.  I guess I need to improve my research skills, and maybe make more visits to hamfest flea markets.  In any case, once again the group on this reflector came through.  My thanks.

73 all,

Ted, KN1CBR    
    
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    Message: 14
    Date: Sat, 16 Jun 2018 23:57:06 -0700
    From: Walter Underwood <wunder at wunderwood.org>
    To: Elecraft Reflector <Elecraft at mailman.qth.net>
    Subject: Re: [Elecraft] OT - Source for Air Variable Capacitors
    Message-ID: <506D8E2A-6EB9-45AD-B905-45C4E448AD64 at wunderwood.org>
    Content-Type: text/plain;	charset=utf-8
    
    For a magnetic loop, the contact resistance of the wipers on typical air variable capacitors causes big losses. That is why he?s specifically looking for vacuum, butterfly, or split stator variable capacitors.
    
    The MFJ butterfly capacitors are reasonably priced, at $70 and $90. MFJ uses them in the mag loop tuners they sell.
    
    wunder
    K6WRU
    Walter Underwood
    CM87wj
    http://observer.wunderwood.org/ (my blog)