Squirrels and rats can be a problem, but mostly my cable chew issues have
been from raccoons. I used to trap them and deport them a few miles.
Now I just I bury my cables. Even a few inches of dirt is enough. Where they
come up out of ground, I sleeve them with cheap plastic sprinkler pipe.
You can splice out the bad areas, but you have to bury, sleeve, or fix
whatever is eating it.
----- Original Message -----
From: "Dave Olean" <k1whs@metrocast.net>
To: <topband@contesting.com>
Sent: Monday, November 09, 2015 2:38 PM
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
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