[TenTec] Orion RF hardening (was Is Jupiter better...)

Stuart Rohre rohre@arlut.utexas.edu
Mon, 1 Apr 2002 21:06:03 -0600


Carter,
You should not have radiation from the 450 ohm line if the line and antenna
are truly balanced.  Is your antenna an end fed Zepp?  That one can have 10
per cent imbalance in the parallel feeders by its nature.  Is the antenna
clear of other conductors and well away from the shack?

We use ladder line with Inverted Double Extended Zepps and Horizontal large
loops at club's Field Day with no field apparent close to the ladder lines,
and no RF in the rigs problems.

I have seen RF in the shack if the coax jumpers to a transmatch are not
tightened all the way and for other loose connection issues.  Even with
attic dipoles, I do not see (at 100 watts) any RF in my shack about 8 feet
below the parallel dipoles.

But, other locations can present unique coupling issues.  I once aided a ham
who had the same vertical as I, and his could not load on 30M with low SWR.
We discovered, since mine could, his was affected by a 30M resonant chimney
flue pipe near his vertical!

73,
Stuart K5KVH