Hello all,
I was trying out my station with a second antenna - an 65-foot End Fed Half Wave. I had built it to the kilowatt level, with a big toroid core on the matching transformer. Instead of a counterpoise, I used an 8-foot ground rod - the kind they sell to ground your house.
Probably needs a counterpoise also...
The far end of the antenna is supported by a monster oak tree on my property. Got it up there with a slingshot.
I hooked up a spare MFJ998RT autotuner to the EFHW and thence to my station through
a 40-foot length of Davis Buryflex RG/8.
It worked fine on the base T41 - decent SWR on 40, 20 & 15M. And it actually worked
on 80 - although the autotuner was clearly struggling.
HOWEVER, when I turned on my KW amp, I pushed the PTT, and the power immediately rose to 950W or so out...without me talking. And somebody on the frequency said "what's that noise?".
I figure that RF is getting back into the T41.
Probably need to stick a counterpoise on the EFHW, and maybe a common mode choke.
My main antenna does not give me any such problems; it's a trap vertical up the hill,
and it has an excellent ground - an Ufer ground, consisting of 80 feet of thick copper wire embedded in a 10 by 70' concrete slab.
I'm trying the EFHW to see if it's any quieter than my vertical. So far, it's about the same.
- Jerry, KF6VB
