Dave:
I have problems with squirrels and rats at my farm with the wiring systems
on my tractors. They chew the wire up to sharpen their teeth. I know you
cannot do this for a thousand foot run, but what I did to keep them away
from the wiring harnesses I put a bag of moth balls in the electrical
compartment behind the dashboard of all three of my tractors. I had to
replace the wiring harness on my Massey-Ferguson 471 last year and it was
$2,800 to replace it. I have not had any more problems with rodents of any
kind since putting the moth balls out. It also keeps the wasps and bees
from building nests in there, also. I know in some states it is illegal to
use moth balls, though. But as I said, I do not think it would work outside
in that big of an area. I have had problems with moles eating through my
buried coax and rotator control cables before and I ended up putting it in
PVC. I have a couple of pecan trees and a lot of oak trees at the farm near
my 160 meter Windom and so far they have not damaged that antenna. I have a
friend north of Jackson and the squirrels eat through his dipole antennas
all the time. Another ham friend here in town sets out traps for them and
then hauls them off to the National Forest and lets them go. That is a
never ending battle, though. The problem I have with Beverages are deer.
Tree limbs are a big problem, also.
73,
Alan, N5PA
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Dave
Olean
Sent: Monday, November 09, 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
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