Topband: A couple of Beverage questions

[Richard (Rick) Karlquist]

Greg - ZL3IX wrote:

> The common mode characteristic impedance is also more or less as 
> expected, but does not seem to be so dependent on the far end 
> termination, leading me to believe that there is considerable loss in 
> this mode.  First question - what should I expect the common mode loss 
> to be for a 2 w/l Bev?  Eznec gives the average gain as -17 dBi, leading 

When I first got my QTH in 1997 I immediately put up the longest
Beverage I had room for, being about 1300 feet, over 2 wavelengths
on 160 meters.  This was also the first Beverage I ever built.
The front to back was terrific, comparing WWV to WWVH, but independent
of termination resistance.  Long story short, only the first 400 feet
were acting as an antenna, due to ground losses.  The remaining 900
feet was just acting as a dummy load to provide a well matched
termination.  I eventually built a current probe and confirmed the bad 
news.  My high conductivity ground is great on transmit, but lousy for 
beverages.  You might want to build a current probe and see how much
current is making it to the far end.

Rick N6RK