[TowerTalk] Salvage Heliax

[Jim Brown]

On 11/4/2021 3:01 PM, Gary wrote:
> How do folks go about salvaging heliax?

Unless it has lightning damage, physical damage, or water penetration 
into the dielectric, it's likely perfectly good. Here's a write-up I did 
about ten years ago about things I learned while adding a lot of used 
and new reel ends to my station.

http://k9yc.com/HardLine.pdf

I suggest that you start by downloading as much as possible of mfr data 
sheets, paying attention to which connectors fit which mfr's line. Hard 
line has been evolving over the years as cell systems have proliferated, 
with much of the evolution centered around making installation go faster.

Continue learning by posting here about specific cable types, to learn 
from the pros who do it for a living, and the OTs who have been through 
it before.

One of the first things I would do is make measurements from one end 
with a well-calibrated vector analyzer, with the other end shorted and 
open, export the data to AC6LA's ZPlots to compute loss parameters, and 
compare with published loss data for the product. Also a good TDR plot 
sweeping at least 500 MHz wide, viewing with software that does the 
inverse FFT of the sweep to display time/length. I use (and recommend) 
the VNWA, designed by DG8SAQ and using his operating software. For these 
preliminary measurements, if there are no connectors on the line, the 
analyzer may be connected with short pigtails for "good enough" data.

73, Jim K9YC