Topband: Measured RG-6 Loss: Solid Copper vs. Copper Clad center conductor

[donovanf at starpower.net]

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 at starpower.net>  
>Subject: Measured RG-6 Loss: Solid Copper vs. Copper Clad center conductor   
>To: topband at 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