[TowerTalk] Ecoflex cable

[Wes Stewart]

About three years ago I purchased some Ecoflex-10 cable assemblies from 
Vibroplex. These had what seemed to be very nicely made PL-259 type connectors 
preinstalled. (Getting lazy in my old age)  It appears that Vibroplex no longer 
sells these but other vendors do.

This note is to report on the performance in the field so far. In addition to 
the ones used as patch cords in the station, I installed one 60 foot length on 
my Rohn fold-over tower from the base to the Yagi on top.  The upper end was 
used as a rotor loop, so it saw that flexing.

Prior to installing this cable I performed characterization measurements using 
my DG8SAQ vector network analyzer (http://sdr-kits.net/VNWA3_Description.html) 
running the supplied software and post processing the s11 data with Zplots 
(http://ac6la.com/zplots1.html).  The VNWA was calibrated with SMA standards but 
of course, measured with SMA-to-UHF adapters.  No attempt was made at that time 
to pick nits and subtract out adapter errors as they are pretty meaningless in 
this application. Cited with ridiculous precision, the loss at 30 MHz was 0.438 dB.

A few days ago I had need to fold over the tower for another purpose and decided 
to remeasure this cable and see how it's fared after nearly three years exposure 
in the Arizona desert.  The present attenuation was 0.483 dB, which is 
remarkably close, especially considering the uncertainties involved.  I am quite 
pleased and wouldn't hesitate to use this wherever flexing is an issue.  I will 
continue to use Heliax where it isn't.

FWIW,

Wes  N7WS