Subject: [NEXTEL-1] Re: New Technology May Alleviate BPL Interference Concerns]

From: [email-masked]
Date: Tue, 09 Dec 2003 13:16:06 -0500

-------- Original Message --------
From: Jack Daniel <[email-masked]>
Subject: Re:  New Technology May Alleviate BPL Interference Concerns

I was involved in some G-line (some call it 'G-string') investigations
many years ago.
It looked like a cheap alternative to coax and compared to braided
cables had lower losses. It didn't pan out mainly because of mechanical
limitations. G-line doesn't like bends and turning corners was out of
the question. As I recall, the RF conduction occurred on the skin of the
conductor and protective insulation interacted considerably. That meant
supports for the cable induced additional losses and had to hold the
conductor several wavelengths away from any other surfaces that
exhibited any RF chgarateristics. We thought we had the ideal
application by running the cable vertically aside the leg of a 400 ft
tower. We found the tower also interacted even when spaced away from the
legs 4 wavelengths. Of course wind and rain changed losses too.

Bottom line; it was little advantage over a large quality coaxial cable
because of the compexity of the installation (launcher mounts and
stamd=off supports, alignment) and the marginal improvement that exusted
in the worse wind/rain case. In other words, it was temperamental and
unpredicable.

Maybe at these higher freqs (we were testing at 450 and 900) and with
design and material improvements it will work now.

The good news: Very low RF 'leakage' perpendicular to the G-line
conductor.

Jack Daniel
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