[R-390] Antenna question

[Barry Hauser]

Say, Tom ...

I dunno how to break this to you, but some famous old (and dead) guys have
hijacked your email identity and are posting the reflector with it.  I could
tell because they left out the codewords "twit" and "HAMMARLUND."

All seriousness aside,  there is some variety in CAT 5 cable.  Some is
intended for runs in ceilings and walls from switches and hubs to outlets
and is typically made up of four twisted pairs of solid core wire so it
works in punch-down telco style connections.  The stranded variety is
usually intended for cordsets with the modular plugs on each end to hookup
from outlet to PC.

It was mentioned that the CAT 5 cable won't hold up long with exposure to
the sun's rays.  However, the high-end plenum cable has a teflon jacket.  I
don't know if the cost has come down on that type -- it tended to be rather
pricey.  But, I'd think it might hold up better with long term outside
exposure.

Philo T. Farnsworth
Hey?!






> On Thu, 18 Jul 2002 20:32:45 -0500 blw <ba.williams@charter.net> writes:
> > Tom,
> >
> > Are you saying that CAT-5 ethernet cable is better than coax?
>
> It depends upon what you want. If you are only receiving or
> transmitting at QRP levels, using a receiver with a balanced input
> available, want to effortlessly null out any currents that are not
> induced in the antenna elements, want to use several antennas
> without having an antenna switch or relay outside and up high,
> don't want to care if lightening zorches your expensive feedline,
> and have boxes of the stuff laying around...yes, CAT 5 is better.
>
> > I wonder why coiling CAT-5 will slow things down so much.
>
> Because "coiling" can allow induced peaks and nulls to develop
> in the line. Remember, those signals have very high bandwidth
> so many resonances can develop along with imbalances. If you
> had instead simply stuffed the cable into a milk jug in a random
> fashion you would not have had a problem. I've run into this
> problem all the time with network installers who are too tidy
> and like to leave extra cable coiled up in the ceiling. I just undo
> the tie-wraps and scramble it into a nice ugly ball.
>
> > I would have to feed 2 dipoles. I guess the extra twisted pairs
> > would be good for additional antennas this fall.
>
> Yup. And you can just make a plexi disk with eight posts around
> and wire up your four dipoles in a radial or fan array.
>
> > Okay, here is another problem. ...The new TV in the den is
> > causing light RFI every 15 kc up and down the bands.
> > The TV is 3 rooms away!!!
>
> The question is how close it is to the antenna. Your receiver may
> be doing it's job and the TV is simply a piece of shit. I would
> first stick a wire in the unbalanced connector and see if I could
> get that TV marker generator directly, and, if so, work on cleaning
> up the TV. How do you do that (I hear you cry)? First make sure
> the HV anode connection (in the piece of shit) is good and there isn't
> a leak somewhere, next put an RFI filter on the power cord of the
> TV, and finally, trade it in for a couple of good books. The kids need
> to read more anyway.
>
> Otto Von Helseng
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