Topband
[Top] [All Lists]

Re: Topband: [Bulk] Why do rodents eat coax?

To: Dave Olean <k1whs@metrocast.net>, topband@contesting.com
Subject: Re: Topband: [Bulk] Why do rodents eat coax?
From: Grant Saviers <grants2@pacbell.net>
Date: Mon, 9 Nov 2015 13:59:18 -0800
List-post: <topband@contesting.com">mailto:topband@contesting.com>
I rented the smallest walk behind trencher from the local Home Depot, it cuts about a 2" wide trench and will go down at least 12". By not getting close to tree trunks to avoid any large roots and to minimize any tree damage, I cut a 300' run through a forest for 1 1/4" conduit. The cable guys here do that with a flat blade shovel like widget and drop in flooded RG6, but for me, the trencher was the way to go. About $100/day, and I think that included the trailer. Of course it depends on soil, roots, and rocks but 100' an hour was no sweat.

Another way, if a tractor is big enough and there is enough space between trees is to pull a cable or conduit/pipe with a Kellems grip attached to the back of a single point ripper. Did that to replace 6000' of 1" pvc to a spring, but some rocky areas did need a ride on trencher. We could pull/bury 200' to 400' at a time of 1" pvc glued pipe about 12" down in CA adobe. Messenger RG6 might pull a long way.

Grant KZ1W


On 11/9/2015 11:38 AM, Dave Olean 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 resis
ta
  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

<Prev in Thread] Current Thread [Next in Thread>