[Lowfer] SIW (WM) in CT

[Garry]

Mike, I notice you mention your normal lowfer antenna current is about 
75 ma. With 1 W input that implies a quite high net resistance of about 
178 ohms. Ground resistance is certainly a part of that but I wonder if 
your variometer to resonant the antenna is an even bigger source of 
resistance. The first variometer I wound used run of the mill magnet 
wire and had way too much DC resistance when enough turns were wound to 
reach the roughly 2mH needed for antenna resonance. I eventually got 
some decent litz wire and lowered the resistance to around 10 ohms. I 
don't recall the total system resistance I ended up with but I'm sure 
the antenna current is at least 150 ma. So I'd suggest you measure the 
DC resistance of your matching inductor (yes, the AC resistance at 185 
kHz will be somewhat different) and if it's high consider working on 
that first. It's surely much easier to improve than the ground system, 
at least in the winter, hi.
-- 
73, Garry, K3SIW, EN52ta, Elgin, IL