You probably have a current fed vertical so you don't have to worry
very much about the voltage on the cap. Any air variable with around
1/4 inch spacing will be fine. It should not be hard to find
something with the value you need--the tune cap in any ham RF amp will
probably be okay as an
My top-loaded vertical needs a series 260pF capacitor at the feedpoint to
match the 53 + j335 impedance (1.825 MHz) to my coax feed.
I have a few different air-variables I could use, but I was wondering what
sort of fixed capacitors would be suitable in this application.
Max power is 1500w. I
Thanks for the cap suggestions everyone, and for the V and I calculations
Tom.
Ideally I'd like the 300pF (or so) vac. variable and so will watch for a
decent deal on one.
In the meantime, I will parallel four 50pF doorknobs (7500v and 1.8A at 1
MHz) and single 100pF variable with .05 plate
I know someone who uses aluminum plates with
HDPE plastic to make a fixed capacitor. Works great
with 1.5kw on Topband. Formulas to get the cap in
reasonably close is in most ARRL RA handbooks. Tweek
with a capacitance meter.
73,
Charlie, N0TT
On Sun, 2 Aug 2015 18:10:57 -0600 Steve Flood
My top-loaded vertical needs a series 260pF capacitor at the feedpoint to
match the 53 + j335 impedance (1.825 MHz) to my coax feed.
I have a few different air-variables I could use, but I was wondering what
sort of fixed capacitors would be suitable in this application.
Max power is 1500w. I
Hi Steve,
I am shunt feeding my 80 ft tower with a stack on top. I first tried air
variables and the loading changed with power. I went to vacuum variables and
all is well. 500pf @ 7.5kV. 73 Price W0RI
On Sunday, August 2, 2015 7:11 PM, Steve Flood kk...@bresnan.net wrote:
My
