[amsat-bb] Exciting Coax

Edward R Cole kl7uw at acsalaska.net
Thu Jan 25 16:53:15 UTC 2018

Don is correct.  In my former work I installed radio systems on boats 
and considered 5-years trouble-free operation "full life cycle".  I 
sealed those cables with a layer of scotch-30 annealing tape with 
Scotch 33+ over that.  The boats were in 27 to 45 foot class so 
subject to considerable saltwater spray.  We also had two 200-foot 
oil well support vessels on Cook Inlet in Alaska.

My Ham Radio use of LMR-400 gets about ten years life, even with 
super diligent sealing.  The aluminum tape shield is subject to 
corrosion in presence of moisture.  Using true hardline like LDF 
cables will outlast LMR cables.  Why they are used in commercial 
radio sites.  I live two miles from Cook Inlet.

My main VHF/UHF transmission line is 120 foot of LDF7-50A which is 
1-5/8 inch in diameter and cost me $1.00/foot new surplus (got a 
160-foot remnant).  It has about 0.27 dB/100 foot loss at 150-MHz.  I 
get about 5w on 1296 with 15w input over a 170-foot combined run of 
LMR-600 & LDF7-50A.

Coax does not live forever - unless used as a dummy load (LOL)

73, Ed - KL7UW
35-years experience in 2-way communications (FCC 2nd class with 
Marine Endorsement)

From: Donald Olson <olsonda1 at yahoo.com>
To: "AMSAT-BB at amsat.org" <AMSAT-BB at amsat.org>
Subject: Re: [amsat-bb] Exciting Coax
Message-ID: <171777450.344072.1516811270343 at mail.yahoo.com>
Content-Type: text/plain; charset=UTF-8

This has been an interesting chain of posts and I have copied it for 
distribution at our club.? Thanks. I will continue to follow it.

However, to those out there that think that you can eliminate water 
in coax with proper sealing, you are only delaying the inevitable, 
especially if you live in a humid climate like New Orleans

73, Ed - KL7UW
Dubus-NA Business mail:
   dubususa at gmail.com 

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