[Lowfer] Coax Caps

[Peter Barick]

>>> we0h@gentekcom.com 02/05/03 05:10PM >>>
"
My EF Johnson 500pf air variable gives me little trouble. I took LPS-1
and
sprayed the brush contacts last summer and it is still working. Of
course my
cap is the size of Bill's final enclosure so it might present a bit of
trouble stuffing it in there. The 3/4th inch pipe variable cap would be
good
as there are no contacts to worry about but it is 21" long. Hi Hi...
.........
Mike>WE0H
"
-----------------

Mike, here's a thought: To obviate the weak link of the wiper on the V
Cap, a short flex wire could be soldered to, say, one of the rotor
plates and then to the frame, as it only turns 180Ds. Those newer Al
solders may be applied here, though I haven't tried it. :-) Your old
Johnson may be the right age for some reconstruction at this point, huh?
Plus, I'd like to know more about Al soldering and none of the shops
here have it. May have to order some. Once saw a demo of propane
soldering of Al plate at the Oshkosh Air Show, boy it was smooth looking
(Was that guy really using Al?).

On Coax Caps, when this topic was raised last (summer?) I went to a
Tesla site (think Ralph, XSR, mentioned) and they made it into an art
form. The site went into some detail on rolling the plates and
dielectrics, and filling and purging the oil pool. The Teslas used it
for HV, H Cur. so it should work at LF, right? BTW, these were furniture
sized objects. Ah, so befitting for large loops!  :-)

Peter