Several topbanders asked if I would measure the DC resistance of the solid
copper and copper clad steel center conductors of the RG-6 coax for which I
published the RF loss measurements. I also measured the quad-shield DC
resistance, both cables measured the same.
Here are my measurement results:
Solid copper: 0.6 ohms per 100 feet
Copper clad steel: 1.9 ohms per 100 feet
Quad shield: 0.3 ohms per 100 feet
It appears that copper clad steel RG-6 is a good choice for remote powered
preamps and relays except for very long cable runs.
When using a remotely powered device its extremely important to prevent even
the slightest moisture entry. RG-6 compression connectors are NOT waterproofed
at the threaded end of the connector, additional waterproofing is absolutely
essential.
The Thomas & Betts NS500 Nut Seal costs only a few cents and it very
effectively waterproofs the connector threads.
http://www.ebay.com/itm/NEW-LRC-AUGAT-THOMAS-BETTS-NS-500-NUT-SEAL-50-LOT-/160703026841
The inside of the connector should be stuffed with STUF Di-Electric Filler to
prevent moisture accumulation from condensation. The finished connection
should first be wrapped with electrical tape, then a final layer of
waterproofing should be applied such as Coax-Seal moldable tape.
73
Frank
W3LPL
---- Original message ----
>Date: Wed, 23 Jan 2013 17:58:31 -0500 (EST)
>From: <donovanf@starpower.net>
>Subject: Measured RG-6 Loss: Solid Copper vs. Copper Clad center conductor
>To: topband@contesting.com
>
>Today I measured the difference in loss (dB per 100 ft) between solid copper
>(SC) center conductor RG-6 vs. copper clad steel (CCS) Quad-Core RG-6 coaxial
>cable. The difference is not significant until cable lengths exceed 350 feet.
> You can see the affect of the steel core at 7 MHz and below in this table.
>
>The cables were manufactured by two different companies, but the relative
>measurements should be valid.
>
> Solid Copper Cable length in
>Freq Copper Clad feet for a 1 dB
>MHz Loss Loss loss difference
>
>1.8 0.3 0.6 350
>3.5 0.4 0.6 500
>7.0 0.6 0.8 500
>10 0.7 0.85 650
>14 0.75 0.9 650
>21 0.9 1.0 1000
>28 1.0 1.1 1000
>
>73
>Frank
>W3LPL
_________________
Topband Reflector
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