Topband: Beverage Frustrations

by way of Bill Tippett <btippett@alum.mit.edu> kb9cry@attbi.com
Wed, 26 Jun 2002 14:30:10 +0100


I mount my terminating resistors in a small Radio Shack 
plastic project box which is attached to a short bamboo 
pole right at the ground rod at ground level.  My 
antenna wires slopes down to that point.  I'd mount them 
at the ground.  Also, I've drilled a couple small holes 
in the bottom of the box to let out any accumulated 
moisture.  I use 12 watts worth of resistors (I only use 
carbon composition types) by paralleling a bunch of 2 
watters in the proper combination.  Finally I wire a gas 
discharge tube (about 150 volt firing spec) to protect 
the whole mess.  Never have had a problem.  One thing 
all should remember, besides lightning, these antennas 
are designed to pick up low band signals and think about 
the signal they pick up when you transmit!

At the transformer end, I only use a DC blocking 
capacitor in series with the coax feed to the shack.  
Finally my cax shield, to the shack, is no connected to 
the ground connection at the transformer end.

I'm also wondering if you're using too small a toroid in 
the transformer.  I don't know the core I use off the 
top of my head, but it is about 1.5 inches OD, I stack 
two on top of each other for less dB loss (per ON4UN), 
and wind them with 20 or 18 gauge wire.  Maybe you're 
using really tiny wires which can't handle the surges?

Hope this helps.  Gd luck,  Phil  KB9CRY