Many have tested various grades of RG-6 shield integrity from HF to
microwave in a lab enviroment.
It does vary, even at HF and low VHF so I suggest sticking to a name brand
and getting the best you can afford as it is more likely to be better over
time. Even a single braid varies in percentage of coverage, mo is mo betta
and quad shield doesnt cost much more.
Be very sure you get the proper connectors that are for the cable you pick.
Carl
----- Original Message -----
From: "Bill Wichers" <billw@waveform.net>
To: <topband@contesting.com>
Sent: Tuesday, March 18, 2014 4:18 PM
Subject: Re: Topband: Andrew RG6 specs ?
Regarding the copper clad steel (CCS) center conductor, you can easily get
RG6 with a solid bare copper (BC) center conductor too. BC center
conductor is important for security cameras (which are baseband), and for
satellite applications (which send DC over the center conductor to power
the LNB at the dish). Since the satellite guys especially are also a very
large market, there are lots of good BC center conductor RG6 variants to
choose from at good prices.
Regarding the braid in the shield, Tom actually did some testing on that
some time ago. I think he took a piece of the dielectric with the bonded
foil ONLY (no braid) and measured essentially the same amount of leakage
as the "regular" coax with the braid. I remember being surprised at that
since I'd always thought of the foil as the high-frequency shield and the
braid for the lower frequency part. I agree with you that I don't think
I'd trust the light-braid RG6 variants for TX though since I'd be
concerned about heating. Even though the foil is a good shield, there just
isn't much metal there to carry the higher currents associated with
transmitting.
BTW, you can even get RG6 with copper braid if you need solderability. It
tends to be a lot more expensive though.
-Bill
[snip]
loss doesn't matter for an RX antenna, but shielding does. Many CATV coax
cables have shielding that is optimized for VHF/UHF, but not so great at
MF
(160M). Many also have a copper clad center conductor, which is fine for
VHF/UHF, but more loss than copper at MF, which makes it less wonderful
for TX.
Take a look at the shield of any coax that you hope to use on MF and HF.
If it's foil plus a thin braid, it will be lossy at MF/HF, and won't be a
very good
shield. If the SWR on the line is low, it may or may not handle much
power.
[snip]
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