[TowerTalk] C3-SS Problems sort-of resolved

[dan hearn]

It sounds as if your beam is coupling into one or more horizontal
conductors. Does your coax turn horizontal at the tower base? You could
also have coupling into horizontal house wiring, metal roof flashing or
a metal ridge ventilation strip. A pretty good test of a horizontal yagi
is to rotate it while listening to a station. You should see deep nulls,
when the ends of the elements are pointed at the station, of several S
units. The signal off the back should be  2-3 S units down. 
  I assume you are using a balun at the feed point. If your coax does
run horizontal 6 feet or so beneath your beam and you cannot take it
thru the roof beneath the tower, I would try inserting several sleeve
baluns in the coax line in the horizontal run, possibly 8ft or so apart.
You could, put several ferrite sleeves on the coax at about the same
spacing and location or coil 4-5 turns of coax around 4" PVC pipe to
make solenoid chokes at about the same spacing. 73, Dan, N5AR

Eric Rosenberg wrote:
> 
> A couple of months ago, it seemed my very early model C-3SS suffered a
> performance degradation.
> 
> Many suggested that I replace the ~100 ft 9913 feedline, so last
> weekend, I did. As it happens, the feedline was 9913 with a 6 ft RG-213
> jumper at the end.  The new feedline is a single piece of RG-213 --
> this time 125 feet long -- the the excess (25-or so ft) neatly coiled
> up outside the shack
> 
> The results were less spectacular than I might have otherwise thought!
> 
> The antennas is ~6-2/2 feet above the peak of the roof on a 4-legged
> roof tower.
> 
> In checking the SWR, it appears to change depending on the position
> (dorection) of the antenna relative to the roof.  Parallel to the peak
> is different than perpendicular to it!
> 
> Is this normal?  My climber, N3OC apparently has a similar experience
> this with his TA-33jr. What a srprise this is!
> 
> A question...will subtracting feedline -- making it closer to what it
> was -- make a difference?
> 
> Thanks in advance,
> 
> Eric W3DQ
> Washington, DC
> 
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