[Elecraft] OT trying to identify "mystery" coax cable

[Ken Roberson]

Lew,

Look up RG9 I think it 52 OHM coax that has two shields.

73 Ken K5DNL

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--- On Wed, 4/13/11, Lew Phelps K6LMP <k6lmp at me.com> wrote:

> From: Lew Phelps K6LMP <k6lmp at me.com>
> Subject: [Elecraft] OT  trying to identify "mystery"  coax cable
> To: "Elecraft Reflector" <elecraft at mailman.qth.net>
> Date: Wednesday, April 13, 2011, 11:58 AM
> I was browsing through the local
> Salvation Army Thrift Store (where I sometimes go looking
> for low-priced antique treasures), and stumbled across a
> 50-foot length of RG-8-type coax cable. At the asking price
> of $6.00, I couldn't pass it up.
> 
> It has Amphenol male "UHF" connectors. And absolutely NO
> markings on the cable itself indicating manufacturer or
> type. The OD of the cable varies from point to point, but
> averages about .405 inch, which puts it in the RG-8b family.
> It is quite flexible, and clearly stranded center conductor,
> not solid.   Capacitance of the 50 foot cable
> was measured 1155 pF, or 23.1 pF per foot, which eliminates
> some RG-8 flavors that have 30 pF per foot.  The only
> distinguishing feature of the cable is that there appears to
> be a wire would spiral-wise (1/2 turn per inch) outside the
> standard foil shield and under the exterior rubber
> sheath.  I've never need that construction before on
> any RG-8 cable.  (I haven't cut it open to verify the
> construction, because I don't want to have to de-solder and
> reconnect the Amphenol connector.) 
> 
> I attached the cable to my dummy load and to the HF output
> of my K3.  Keying the transmitter at 12 watts produces
> an SWR of 1.05:1 (external SWR meter) on all bands up to 6
> meters, and continuity checks confirm that the cable has
> neither short circuit between shield and cable nor open
> circuit.  In other words, it appears fit for duty.
> 
> Two questions;
> 1. Anything else I can or should do to check the cable and
> make sure it's OK to use?  (Unfortunately, I do not own
> or have access to an antenna analyzer.)  
> 2.  Based on the "spiral winding" between the shield
> and outer coverk does anyone have an idea what specific
> cable this might be?
> 
> Thanks, and 73
> 
> Lew K6LMP
> 
> 
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