Topband: Zo of an individual CAT5 twisted pair

Jim Garland 4cx250b at miamioh.edu
Mon Aug 12 12:38:57 EDT 2013


I believe that if you parallel two twisted pairs of a CAT5 cable, you'll
have a 50 ohm transmission line.(Each twisted pair is 100 ohms).  I've tried
this with CAT5e cable and find it works well, even for transmitting, up to
about 100W.  The VSWR match was very close to 50 ohms. The problem is that
there is very poor noise rejection. When I used it as transmission line for
a receive antenna I picked up all the computer hash, fluorescent lights,
etc. in the area. I quickly abandoned the experiment and went back to coax
cable.
73,
Jim W8ZR

> -----Original Message-----
> From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of James
> Rodenkirch
> Sent: Monday, August 12, 2013 10:32 AM
> To: topband at contesting.com
> Subject: Topband: Zo of an individual CAT5 twisted pair
> Importance: High
> 
> In an earlier post to this reflector, Carlos, N4IS, mentions using one
pair of twisted wires
> out of a CAT5 cable to feed the delta loop antenna used by T6LJ.
> 
> I am assembling the pieces/components needed to put an "FO0AAA style"
delta loop
> receive antenna up and want to use the twisted pair cable as well.,
> 
> My question is:
> 
>  Does it matter which twisted pair of wires I use?
> 
> Thanks, in advance, for any thoughts....72, Jim Rodenkirch K9JWV
> 
> _________________
> Topband Reflector



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