Topband: Skin Effect of RG-6U

[Dan Edward Dba East edwards]

oddly enough, I found some 'Direct TV High Definition' RG-6 that has a solid coppercenter conductor. it seems to behave better at low frequ's than the copper cladsteel. less loss and closer to 75 ohms Zo. ( i get 79 ohms on 160m with my VNA )

Zo seems to rise as you down in freq. less so with the solid copper center cond.
FWIW, 73, W5XZ, dan
--- On Tue, 2/1/11, Jim Brown <jim at audiosystemsgroup.com> wrote:

From: Jim Brown <jim at audiosystemsgroup.com>
Subject: Re: Topband: Skin Effect of RG-6U
To: topband at contesting.com
Date: Tuesday, February 1, 2011, 12:31 PM

On 1/31/2011 3:02 PM, Dennis W0JX wrote:
> I have found that the quality, and therefore the loss, of RG-6 cable varies quite a bit. On the average, I measure about 14 ohms of resistance in 500 feet if shorted at the far end. Recently, I put up a dual flag RX antenna and felt that the sensitivity was far down from normal. It turned out that my  resistance was about 20 ohms for 500 feet. I discovered some oxidized connections in a splice and also some water contaminated aluminum shielding. If you are going to use long runs of RG-6, I recommend Quad with the larger center conductor, very careful sealing of any splices to prevent moisture, and if available, flooded cable to seal any pinholes.

Great advice.  Also, stick to major mfrs like Belden and Commscope.

>   
> I have found that the low-price Home Depot stuff has a PVC jacket which is easily cut and exposes the braid to moisture. The aluminum shield then starts oxidizing.

See http://audiosystemsgroup.com/Coax-Stubs.pdf

73, Jim K9YC
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UR RST IS ... ... ..9 QSB QSB - hw? BK