I had the same problem but on a much shorter run.....I put the coax inside
flared plastic pipe....the type that slips together....no glue needed.
My problem solved.
If I had a run as long as yours I think I would just cut out the bad length
and put on F connectors.
Just keep doing this to delay the replacement of the whole length.
73
David Harmon
K6XYZ
Sperry, OK
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Dave
Olean
Sent: Monday, November 9, 2015 1:39 PM
To: topband@contesting.com
Subject: Topband: Why do rodents eat coax?
I was transmitting on 160 last week, and after calling a CQ I noted that the
background noise from one of my beverages dropped to almost nothing.
Something obviously broke right then. All checks pointed to something
external to the shack. I finally got out in the woods and checked the
antenna system. All looked great. I used my new SARK-110 vector network
analyzer and saw very believable results when connected to my 1100 ft long
Europe beverage: about 75 ohms impedance and a VSWR that fluctuated between
1.5 and maybe 1.8:1 across the freq range. I double checked the entire
beverage run for shorts or anomalies, and even took apart the termination
box to make sure all was OK. The last thing left was the 1000 ft run of
flooded RG-6 coax. I had run the cable on the ground back to the house about
2 years ago. It was mostly invisible now, being covered with leaves and moss
etc etc. A TDR check showed gross "bad" things and a VOM test across the
center pin to ground showed a resista nce of 35 ohms while the far end was
terminated in a 75 ohm load. Obviously the cable was compromised. I made a
quick inspection and found a few spots where small animals had chewed on the
coax enough to break through the outer plastic covering and into the braid
and aluminum foil shield. Water and gunk have caused a low resistance
between center pin and the shield.
What are my options now? I don't want to spend another $150 for another
roll of coax just so a squirrel can feast on the PVC. Should I route the
coax in the air and away from small mouths? That is one option. It seems
that digging a 1000 ft trench thru the woods and burying it would work, but
it would be an awful big chore for a 70 year old doofus. I doubt that I
could manage that. If I run the coax above ground, I run the risk of picking
up noise etc. I also worry about falling limbs and old dead trees falling on
it. With a few beverages in the woods, I can't afford to spend $150 each
time an animal feasts on it. I need to do something different!
Incidentally, the beverage still has great directivity, but signals are
very weak with the bad cable. It is barely useable now as a result.
73
Dave K1WHS
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
|