Gene Bigham wrote:
> I know this is not about amplifiers, except for being able to use one on a
> trapped antenna, but has anyone found a set of traps for 40 and 80 that can
> handle a legal amplifier output?
You have two problems in making traps: current and voltage.
I made some using 5KV doorknobs (for 160/80) and exploded the doorknobs
at less than legal power. This was a result of heating as a result of
inadequate current capacity. They also drifted a bit before blowing up.
Now I have one made of a 6 KV mica capacitor that is about 3" x 4" x
3" which worked fine at QRO.
The trick with traps is to make sure they are NOT resonant at a
frequency that you will operate on! The voltage across a parallel
resonant circuit increases enormously as you get close to resonance.
For example, my 160/80 meter inverted L (used for CW only) trap is
resonant at about 3480 KHz. The impedance in the lower part of the band
is still high enough to isolate the 160 M section, but the voltage isn't
astronomical.
You can make traps out of coax which will handle the power. Just google
'coax traps' and you'll find some information. They are heavy, though.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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