I posted earlier on the list (31 January 2011 ) problems we had with some
cheap ebay "satellite cable" CCS RG6 that I was using on a long run to 160m
Beverages. The 250m reels came from different suppliers, though both of Chinese
origin.
"The measured loss in the first 250m segment was ~ 6dB and about ~9dB in the
second segment, 15dB total over 500m. This is way higher than published figures
(eg at http://www.timesmicrowave.com/cgi-bin/calculate.pl) which suggest about
3dB per 250m."
This is in line with your attenuation measurments of CCS (0.6 dB loss per 100
ft at 1.8MHz) , but shows that cheap cable can be even worse!
I assumed that this cable was particularly bad at lower frequencies because
of "value engineering" re the thickness of the copper coating.
Rudy N6LF gives the skin depth at 2MHz as 40uM (Conductors for HF Antennas,
Rudy Severns, QEX November/December 2000) and I guess that some CCS cable has
copper covering much thinner than that!
No doubt quality Comscope or Belden is better, but we stripped out the RG6 and
used solid copper CX167 instead, more expensive but very useable over a 1km
feed run.
Jeremy G3XDK/G4AQG
On 24 Jan 2013, at 02:28, <donovanf@starpower.net> <donovanf@starpower.net>
wrote:
> Hi Mike,
>
> Obviously I had computers on my mind...
>
> Yes, of course I meant to say quad-shield RG-6 CATV cable. I'll provide the
> manufacturers and part numbers in a subsequent e-mail, but its just typical
> inexpensive ebay RG-6 CATV cable.
>
> Inexpensive RG-6 with a copper clad steel (CCS) center conductor is much more
> widely available than solid copper, especially in desirable options such as a
> tough polyethylene (PE) jacket and flooded RG-6. CCS looks like a reasonable
> choice except for very long cable runs on 160 and 80 meters. A copper clad
> center conductor may be a problem if a device (e.g. a preamp or relay) is
> remotely powered through the coaxial cable.
>
> 73
> Frank
> W3LPL
>
> ---- Original message ----
>> Date: Wed, 23 Jan 2013 19:56:40 -0600
>> From: Mike Waters <mikewate@gmail.com>
>> Subject: Re: Topband: Measured RG-6 Loss: Solid Copper vs. Copper Clad
>> center conductor
>> To: topband <topband@contesting.com>
>>
>> Hello Frank,
>>
>> Thank you for this, but you meant "quad-shield" instead of
>> "quad-core", didn't you? I've never heard of coax with 4
>> cores, unless you mean the quad-coax stuff where the jackets
>> are all joined together.
>>
>> Data on the coax companies and part numbers might be useful,
>> if you have it handy.
>>
>> 73, Mike
>> www.w0btu.com
>>
>> On Wed, Jan 23, 2013 at 4:58 PM, <donovanf@starpower.net>
>> wrote:
>>
>> copper clad steel (CCS) Quad-Core RG-6 coaxial cable.
> _________________
> Topband Reflector
_________________
Topband Reflector
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