Can anyone explain why the BCB harmonics/qrm on my inverted L
is (lets say) S-8 on 1.830 , but on my shunt fed tower it's only
about S-1 ?
My tower is delta/shunt fed with about 350pf cap at the feed point.
Lots of radials.
As far as I can tell, the tower is exactly on par with DX signals
or just slightly better (at times) than the inverted L. For Stateside
and Carribean the inverted L is about 10db better. On local (ve1)
signals the tower is down by almost 20db. from the L
I DO have an RF problem in the shack using the tower and can't
transmit on it at the moment as things in the shack get hot and SWR
goes up after the amp is in line. 2 weeks ago I fried a transistor
in my 736's keying circuit due to some stray RF that I just can't put
my finger on.
Both the inverted L and the tower are only 25-30 feet away from the
shack. AHA! you say, but wait. The inverted L is the closer of the
two and I have absolutey NO rf problems with the L, or any other
antennas near the shack at similiar distances.
Anyway, back to the original post. Does anyone know why the BCB
qrm is so much lower on the tower? Dya suppose it's because the
tower has a much lower angle of radiation?
My inverted L incidentally is : 165'+ of wire.
50' near vertical, then 60' near horizontal, then the remainder
sloped backed to earth at about 45 deg angle in another direction.
I am constantly amazed I can work any DX on it, but living near
a swampy area must not hurt it any.
Any comments, questions, solutions, theories on either the RF problem
or the fact the tower is less (a lot less) prone the harmonics.
Maybe 'cuz it's grounded? ............-nah.........
MIKE
Michael & Coreen Smith (AA Antennas & Wynder Photography)
271 Smith Rd, Waterville,
Sunbury Co.,NB, Canada
E2V 3V6
Ham call=ve9aa / ve9ms/b (ex-cy0aa,ve1mq,ve1btt)
6M Vhf buffs;
See the *NEW* AA Antenna web page at:
http://members.tripod.com/~ve9aa/index.html
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