[Lowfer] Active Whips

[JD]

I'm glad you mentioned the separate battery power approach, Tom.  I thought 
I might be something of a wacko loner in using that method myself, since one 
never seems to see mention of it anywhere...but it is definitely the more 
effective way at the lowest frequencies of keeping out noise and reducing 
signal loss.

Someone taking a casual look at my antenna setup (a 40 ft vertical mast 
feeding a buffer amp at ground level) might not think of it as an active 
whip, but electrically it's no different from an active whip atop a pole 
reaching the same height.  The main differences are logistical: I don't have 
to lower it if I want to replace something or recharge the battery, and I 
have 30-some fewer feet of coax to worry about.

With no coupler network at the amplifier end, the only potentially lossy 
element would be a ground isolation transformer at the receiver end.  But 
since I've gone mostly battery powered and almost never operate the radio 
from AC mains these days, I let the antenna ground be the radio's RF ground 
as well and don't bother with any isolation.  Despite the antenna sitting in 
a 60 Hz electric field that reaches 5 V/m on a bad day, there's no sign of 
common mode conduction from anything except sometimes the computer, which is 
also battery powered and usually easy enough to fix.

John