Barrett wrote:
Some one sent me an email and said these will do the job. Ceramic capacitor
disk 10KV/1000pF. Do you think these would work?

I don't know about those particular ones. Some ceramic
capacitors are meant to be DC biased for bypass service.
I once tried to use disc ceramic caps across my ladder-
line. They caught on fire because they were not rated for
AC service and lit up the night sky.

Someone told me the ceramic insulator was actually
trying to physically vibrate at the RF frequency and
friction heated it up. I don't know if your capacitors
are rated for AC operation.

A friend of mine used silver mica capacitors for his
traps and they worked fine.

This is my first attempt at making traps and I do not fully understand how
they work. I am willing to learn as this is what makes the hobby great but I
cannot find enough step by step info to lead me in the right direction.

-------trap----------FP----------trap-------

An ideal trap is parallel resonant with a high Q. That
gives it a very high impedance at the resonant frequency
and acts somewhat like an open circuit at the resonant
frequency blocking the flow of current to the outer
parts of the dipole. At the resonant frequency, the
inductive reactance and capacitive reactance are equal.
A Grid Dip Meter will indicate the resonant frequency.

At 1/2 that resonant frequency, the inductive reactance
goes down and the capacitive reactance goes up so the
"trap" acts like a loading coil instead of an open
circuit on the lower frequency.

Traps can be made out of coax if you are interested.
The coiled outer shield provides the inductance and
the capacitance is provided by the center-wire-to-
shield capacitance.

Kraus talks about self-resonant traps with no physical
capacitors. The inter-winding capacitance of the coil
wire supplies the necessary capacitance.
--
73, Cecil http://www.w5dxp.com