[ADXA] Get 160m inv L to 80m?

[Jussi Eloranta]

Hi Pat,

On 2/20/25 11:09, Pat Patterson wrote:
> I use a coaxial trap...RG214 on a piece of 4" thin wall PVC. Trap 
> resonates at 3.45 MHz.
>
> Looked at using a vacuum relay...lower losses but more complexity.
>
Thanks. Yes, I would like to avoid relays... I have currently a shunt 
coil in place so that I can get the feedpoint impedance close to 50 ohm 
on 160m. With that coil in place, I checked the antenna with analyzer 
and noticed that there is some sort of resonance very close to 3.5 MHz 
(X = 0) but there R is around 5 - 10 Ohms (with the 160m shunt coil in 
place). Of course, probably need to do eznec to make sure that this does 
not end up being an EME antenna (take off angle towards the moon) :-)

Can you give some more details on the trap? Or 1:9 UNUN would also do 
the trick I guess. But that would need to be switched in and out.

Thanks,

Jussi (AA6KJ)