[c-nsp] DS3 Length over RG-6 or RG-59

[Jay Hennigan]

On 9/22/10 1:31 PM, Peder wrote:
> Does anybody have a good rule of thumb as to what type of coax to use for
> DS3 over various distances?  I know it has to be 75ohm, but have read it can
> be RG-59 or RG-6.  Also, on the RG-59 I have seen solid core and braided.
> We have to run a cable about 250' to the telco equipment thru a messy
> ceiling, so we only want to do it once with the correct cable.  In the lab,
> we just use cheap RG-59 but I don't know if it will have issues over a
> distance of 250'.  Thanks.

I would recommend 734 type cable which is designed for DS3.  It is
similar in size to RG-59 but made to better tolerances than you're
likely to find in RG-59.  It's available in figure-8 twin configuration
specifically for DS3 transmit/receive.

The cable you'll typically find these days sold as RG-59 is designed for
TV distribution and often has copper-clad steel center conductor instead
of pure copper as well as aluminum foil shield with drain wires instead
of copper braid.  Terminating this stuff with BNC connectors is a pain.
 It's designed for the F-type connectors used in cable TV.

Also ensure that you use 75-ohm BNC connectors.  The insulator is shaped
differently than the normal 50-ohm type commonly available.

--
Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
Impulse Internet Service  -  http://www.impulse.net/
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