Andy wrote:
I have nothing here to measure the Q of the trap.
Is there another way of working out the correct frequency needed for the
trap?

Sorry, I would just be guessing. I made my 40m traps
resonant on 7.4 MHz and they worked well over the
40m band. But I never made any measurements or A/B
comparisons.

The traps are made from RG58 C/U. I think these are a low Q but I'm not
sure.

The following web page might be of interest:

http://www.seed-solutions.com/gregor...n/CoaxTrap.htm
--
73, Cecil http://www.w5dxp.com