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Re: Survey Results - Yagi Beam Combo






From: Robson Gomes@MLX on 16/12/98 09:19

Hi Brook

I am the person who sent the comments below. Thanks for the
suggestions. Regarding the holes the problem was that they
really did not fit with the U clamps that came with the 435-18C.

73 de Robson - PY1DGV

 ******* Comments *******
>
> >>>>>>>>>>>>>>>>> KLM Antennas:
>
> --------
> The 435-18C mounting plate came with wrong holes drilled.
> After 5 years at 15 Km from beach I see corrosion on the KLM 2M-14C
> balun.

All of the circular KLMs have a mounting plate set-up that was
engineered without taking into consideration of the weight misbalance
caused by the addition of feed line or pre-amp to the antenna.  I have
had to move or redrill the mount set-up on each of the KLMs I have
owned.

> --------
> After 5 years I am having difficulties to copy Oscar 10. But not sure
> if this is really due to antenna degradation. Terrestrial operation
> seems to be good.
> --------

The KLM 2M-22C and 2M-14C use a PC board that is exposed to the
elements.
When I installed my 2M-22C, I fitted a small plastic cover over the PC
board.  I'm sure this helped protect the relay and DC polarity input
jack from some corrosion, however, because the plastic was not UV
protected it has since desinegrated.  I would suggest to KLM to devise
some sort of cover for the PC board.  Better yet, a box like used on the
435-40CX.  The person that sent the above comment could be having
another
trouble I had with my 2 meter circular KLMs.  The SO-239 connector
jack is mounted in a plastic cap that fits over a piece of PVC tube.
Inside the tube is where the two pieces of coaxal balun are soldered to
the connector.  Considerable stress is placed on this assembly as this
is where your coaxal feed is connected to the antenna.  Mine pulled
apart here.  One side of the ground became disconnected and SWR was
always bad when it rained.  I have since constructed a replacement
assembly which uses a water tight metal box and now has a "N" connector.


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