[UK-CONTEST] OT: 20m Trap design

[James Hill]

Hi Guys,

I know there are some good antenna brains on here.....

Basically, my 40m Carolina Windom is shot (havent got it down for 
autopsy yet), and I'm looking to replace it with a 20m vertical (half 
wave CB type at the correct length, with the matching unit removed from 
the bottom).

However, my 80m inverted L does not seem to work too well on 40m (tunes 
up at 1:1), but appears to be terribly inefficient on both TX & RX. 
Works fine on other bands (even managed to work 3B7 on 17m with it!).

What I plan to do, is something along the lines of the "battle creek 
special", and put a 20m trap on the top of the vertical, and extend it 
with wire to the top of the tree at the bottom of the garden, to make it 
good for 40m too.

I've googled for trap designs, and got designs for virtually every type 
of trap, except the type that I want!

I've read a lot about coaxial traps, and that appears to be the way to 
go, as I have drum after drum of RG58 here that I will be able to use. 
Power wise, then 100w tops will be the order of the day, no QRO here! 
Although an LC type trap will be considered, if it's quite easy to make, 
and I have the required capacitors kicking around.

Any thoughts? and more importantly, links to any designs would be 
appreciated!

Thanks,

James G0FHM