[Antennas] Re: Thank you All!

[John Tait]

Hi Mick..
        Mechanically, doorknob caps are circular, with a china body (hence
the "doorknob" tag). They can be wire ended, tag ended, or have threaded
mounting holes, as in the case of the larger ones. They vary in size from
about 1/2" diameter, up to gigantic ones of 2" diameter. They are usually
seen in commercial TXs, amplifiers, ATUs etc, and in the better quality
Amateur gear. They are used where large RF currents and voltages are
present.  High voltage disc ceramics etc may be able to handle high voltages
OK, but are not up to coping with high RF currents.. Doorknob caps are
extremely expensive if bought new, but there should be lots available very
cheaply at flea markets etc.
     I hope this helps
           Vy 73
             de
          John EI7BA   http://www.iol.ie/~bravo/



> Dear Ron,
> I Have seen reference to these door knob capacitors over the years but
never
> seen a photo, drawing or  a live one, so I have a question to ask &  I bet
I
> am not the only one who would like to ask it.
> My question is "what is a door knob cap" and how is the construction of
> these different to any other  capacitor and what is there special place in
> the world of capacitors.
> Regards Michael Harley,
> Curator "The Radio Shack" Caboolture Historical Village, Brisbane
Australia.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Original Message -----
> From: "Ron Bracklow" <n6pww@earthlink.net>
>
>
> > Wow, thank you All for your help in offering the door knob caps and also
> the
> > locations of where to purchase them.
> SNIP
> > Ron, N6PWW
>
>
> - - -
>
> Your moderator for this list is:
> Larry Wilson KE1HZ antennas-owner@mailman.qth.net
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