Hello from Poland,
I've just put few Beverage's on my QTH and however they're working fine (I can
hear DX signals that are completely absent on other antennas), I wonder if
there is still sth I should do about my feedlines.
Last weekend I've done a test described in ON4UN's book - I shorted the coax
center and shield at the bev. feed point (after disconnecting it from the
antenna) and found that there are still some signals present on my receiver,
even some of them are quite strong. That happens mostly on AM broadcast
stations, but on 80/40m I can also hear a lot of signals... Well, in most of
cases they're not moving S-meter at all, but they are there. John ON4UN says in
his book that after such a test "..your receiver should be completely dead".
So, mine is not.
By switching beetween the coaxes I found that the strenght of those signals
does not depend on lenght of the feedline, but on the direction where it goes.
Few more details:
- the longest feedline is 140m long, the shortest 60m
- all feedlines are buried
- each coax's shield is grounded 15-20m away from the antenna feed point, the
longest one is grounded every 40m; the main coax (between the external switcher
and shack) is also grounded when it enters the house
- of course the equipment in the shack is grounded with an independent ground
rod
- what is NOT grounded is the external remote switcher. I decided not to ground
it, because it's placed very close to my K9AY and it's ground rod
I use separated primary and secondary windings in all xfmr's. After installing
them I've noticed the noise level is S 1,5 down, and beverage's are generally
silent, but as I've written before - still wondering if there is sth more to do
regarding the feedlines. Is this really possible that a feedline is so silent
like ON4UN says???
Best 73
Mac SP2XF
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