[AMRadio] Antenna tuner info

Brett gazdzinski brett.gazdzinski at verizonbusiness.com
Wed Jan 10 08:34:15 EST 2007

As I think about building a tuner, I was 
wondering what size components would be needed
for my power levels.
The pair of 813's can run up to 700 watts
of carrier output, but I usually turn it down
to about 500 watts out, around 1500 watts pep.

the antenna will likely be about 100 feet
in a flat top setup, up about 30 feet, fed with 
about 30 feet of open wire line, made with #12
wire spaced an inch or two apart.

Cardwell is selling new caps, model 153-11-1 100pf 7000 volt
for about $100.00 (for a shiny new cap).
They also make dual caps and higher volt caps up to 9000
volts, but other models have a $125.00 setup fee if they 
are not in stock.

Would 7000 volts be enough for most situations?
What size copper wire to make the coil with?
Bigger is likely better, but what is the minimum
size that would work, #12, #10?

Does anyone know what sort of parts were used in the
Johnson KW matchbox?

The ARRL handbook says for 250 watts of AM, 4500 volt
caps and #14 wire are good.

Another thing I was wondering about is:


Looks like I could just hook up the feedline
on that to a balanced tuner and have it work well?

Or, what do you guys use for GOOD wire and rope?
The rope is in tree's, and the wind rubs it some,
the best stuff from home depot holds up 4 or 5 years
before it looks bad enough to change out.
Anything better out there?

I used to use radio shack copper clad antenna wire,
but of course they no longer sell that.

Any info will be helpful, thanks,


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