Weird antenna problem

[Schichler, Alfred (GE EntSol, Digital Energy)]

No, the connectors are UHF (PL-259). I don't think they have the same
problem. At least the better ones don't.
The next time it happens, I plan to measure across the PL-259 in the
shack. It should read a short because of the loading coil right across
the coax at the base of the vertical. If it reads open, I'll know there
is an open circuit most likely at the lightning arrestor. Then I can try
narrowing it down to exactly where.
 

-----Original Message-----
From: Boat Anchor Owners and Collectors List
[mailto:BOATANCHORS at LISTS.TEMPE.GOV] On Behalf Of Al Parker
Sent: Tuesday, June 23, 2009 4:32 PM
To: BOATANCHORS at LISTS.TEMPE.GOV
Subject: Re: Weird antenna problem

HI Al,
    Are the connectors type N?  If so, is there any physical pull on the
coax line that would tend to stretch it?.  It's possible for the center
pin of the male connector to back up into the body a little bit, thus
tending to disconnect it.
    It's happened to me with a 50ft vertical run of RG-8 size coax up a
crankup/rotatable tower to a beam.  At first it would remake the
connection with the application of RF (1kw helped best).  Then finally
nothing would help short of redoing the connector.  Because of the
crankup tower, I was unable to support the cable at intermediate points.
73,
Al, W8UT
New Bern, NC
www.boatanchors.org
www.hammarlund.info

"there is nothing -absolutely nothing- half as much worth doing as
simply messing about in boats."
   Ratty, to Mole


----- Original Message ----- 
From: "Schichler, Alfred (GE EntSol, Digital Energy)" 
<Alfred.Schichler at GE.COM>
To: <BOATANCHORS at LISTS.TEMPE.GOV>
Sent: Tuesday, June 23, 2009 10:05 AM
Subject: [BOATANCHORS-TEMPE] Weird antenna problem


I'm not sure if this is the right group to ask about this problem, but I
figure I'll give it a shot:

Every so often, when I'm using my Butternut vertical mounted on the
garage roof, I notice that signals are way down, like more than 20 dB
down, almost like no antenna or a shorted antenna.
Well, I discovered that if I go in the garage (where there is a
lightning arrestor installed at the 75 ohm and 50 ohm coax junction) and
disconnect the lightning arrestor and squirt some contact cleaner on the
connectors, it works fine again. This happens every few months or so.
I just bought a new lightning arrestor last month, and I took a wire
brush to all the connectors and adapters connected to it, but the
problem still keeps coming back. (It just happened last night). I guess
it's possible that one of the coax connectors has an intermittent
connection, but it didn't look that way when I put an MFJ antenna
analyzer on it. I could only check one of the connectors though.
It's not a real serious problem since it's not hard to fix
(temporarily), but I was wondering if anyone has ever heard of anything
similar and found the cause. (Static discharge of some sort maybe?)

Thanks,
Al, WA2AS




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