Topband: Why do rodents eat coax?

[Michael Clarson]

Dave: For some reason, a lot of animals like to chew on or eat PVC. That is
why cats chew on line cords. I had a run of RG213 on the ground in my
suburban yard, Squirrels chewed through it 3 times in 5 years. I replaced
it with a polyethylene jacket cable, and its been left alone for 7 years so
far. I know Polyethylene is critter resistant, not sure about other
polyolefins. Check out RG-6 made for direct burial. Many have a
polyethylene jacket. You might also try putting some voltage on the shield
to ground. Once the critter breaks through the jacket, he'll find a
surprise inside. Not too much -- just enough to supply a few milliamperes.
--Mike, WV2ZOW

On Mon, Nov 9, 2015 at 2:38 PM, Dave Olean <k1whs at metrocast.net> wrote:

> 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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