Ecoflex cable

[Wes Stewart-2]

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

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[Mike Harris-9]

I installed Ecoflex 10 cable from the shack to the top of my tower in
2008. A year or two ago it was mentioned and illustrated in the RSGB
"RadCom" magazine the potential problem of screen foil break up and
possible centre conductor migration through the foam dielectric in
sections of this type of cable at places of repeated flexing.

My two runs of Ecoflex 10 terminate at the top of the tower with two
extension runs providing the a rotator loop and continuing onwards to
the HF and 6m beams on an eight foot mast above the top bearing. One run
was Ecoflex 10 the other was RG213 type.

Recently I removed both extension cables for destructive inspection in
the area of the rotator loop.

The copper foil screen of the Ecoflex 10 was seriously cracked, in some
places almost to the point of complete severance. The braid element of
the screen which is not particularly dense was OK.

The RG213 type cable showed no sign of damage whatsoever.

Naturally a rotator loop over a period of years takes a hammering and it
seems this sort of foam, braid, foil cable is not first choice for the job.

Two replacement rotator loop runs of RG213 type cable have now been
installed from the top of the tower to the antennas. The extra loss of
these short lengths at HF and 6m are in my case insignificant given that
the full run length shack to antenna is approximately 160 feet.

My only experience is with Ecoflex 10, cable from other manufacturers
may behave differently.

Regards,

Mike VP8NO

On 23/08/2017 17:22, Wes Stewart wrote:

> 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

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