Need disc ceramic capacitors- Comet GP-15 antenna

Submitted by K3RSJ on Thu, 02/14/2019 - 21:06
Forums: 
Help Wanted

My junk box is depleted and I need 500 VDC Disc ceramic (approx1/4 in in size) capacitors.

24, 27, and13 pf

more or less pf is fine, small silver mica may work (size is critical)

Or does anyone know a piece part source?

Note, for owners of Comet GP-15 antennas, these are the parts that will fail.

Distributor does not stock replacement parts

73, Bob K3RSJ

N3ADF - Fri, 02/15/2019 - 06:49

I can't help you on the capacitors but I'm very curious how the capacitors are used in the antenna.  The Comet GP-15 is a 6m/2m/70cm antenna.  Are the capacitors used to isolate different parts of the antenna for each band?  And what causes the capacitors to fail; high power?  I have a GP-9 (2m/70cm) and wonder if it is of simular design.

73, Jim - N3ADF

 

K3HMX - Fri, 02/15/2019 - 09:25

Bob,

I’ve got some of each, though the 13pF are rectangular - need to look up their composition. How many of each do you need?

-Brian Mary 

K3RSJ - Sun, 02/17/2019 - 20:05

Thanks Guys, I can't attach pix, so if you send me your email addresses I can attach pix for both of you.

This antenna is superbly engineered.  Caps can wear out over time, but I suspect nearby static discharges over time ultimatly caused failure.

Brian, what are the dimensions compared to a small (`1/4 in) disc ceramic?

Size is critical.

73, Bob