Topband: sloper interaction
Jim Jarvis
jimjarvis at comcast.net
Sat Dec 4 10:08:59 EST 2004
Dave,
You can't have both slopers up at the same time, that
close together, without interaction. Pull the 9INN
back alongside the tower, and coil it up at the bottom,
and try the experiment again. See if anything changes.
But do it at low power, not at a KW, and closely monitor
the vswr on the antenna you're driving.
There are questions about how a quarter wave sloper works...
and if you believe the tower-image idea, and your rcs4 was
48' up the tower, God knows what voltage was presented across
the relays. Or currents were induced elsewhere in the antenna
system, like rotors. Inspection of the guts of the switch box might
be entertaining!
If you have the real estate for 133' wire, can you put up
ANOTHER 9INN sloper, and feed the pair of them as a loaded
dipole? It'd be more sanitary. Or, less SloPPy, to quote Tom Rauch.
My personal favorite, however, would be a combination of some
top loading wires on the tower, a decent ground radial system, and
shunt feed for 160. 50' stick isn't high enough, really, to
support wires for this frequency.
N2EA
jimjarvis at ieee.org
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