Topband: Using CAT5 in place of coax (was video baluns)

ZR zr at jeremy.mv.com
Mon May 7 18:45:28 PDT 2012


For about 7 years Ive run 250' to the trailer at the base of the big tower 
where it then went another 150' after a router to a microwave Internet link.

It was tied to the same bundle carrying all the hardline TX coaxes plus 
control cables for 4 rotators plus relay switching boxes for stack phasing. 
All carried on 1/4" EHS or on Rohn 45 legs. Never had a trace of problems 
even in a 2 transmitter HF contest or 1200-1500W on VHF bands.

At least the 240VAC to the trailer was on its own 1/4" EHS run about 6' 
away.

Carl
KM1H



----- Original Message ----- 
From: "Kevin" <kevin.stover at mediacombb.net>
To: <topband at contesting.com>
Sent: Monday, May 07, 2012 8:37 PM
Subject: Re: Topband: Using CAT5 in place of coax (was video baluns)


> That's why it's rated at 100 meters max distance when used for networking.
> Now before everybody breaks their fingers posting anecdotal evidence to
> the contrary I have done the same.
>
> It worked out great, till we starting loading that segment down. That
> 400' run was replaced with fiber inside a month. There's all sorts of
> stuff people do with CAT5/6 that isn't supposed to be done, like running
> it parallel to or in the same conduit as AC power. Using it for a
> transmission line has got to be right up there.
>
> Remember, I am only the messenger, the IEEE came up with these "rules".
>
>
> On 05/07/2012 07:07 PM, Rick Karlquist wrote:
>> I did some careful measurements of CAT5 cable a few years ago
>> using a 4 port network analyzer (NOT a 2 port VNA with baluns).
>> On my random sample, the characteristic impedance was within
>> 5% of 100 ohms.  The cable is fairly lossy, which is no
>> surprise given the tiny wires.  There doesn't seem to be
>> any compelling reason to use it in place of RG-6.
>>
>> Rick N6RK
>>
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>>
>
>
> -- 
> R. Kevin Stover
> AC0H
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
>
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