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Re: [IRCA] Cable connectors
So what you're saying Craig, is that you used unshielded CAT-5,
and your tests suggest that by running it along the ground
( as would be usual for beverages at the beach ) that tends to
mimic the effect of a shield ?
I would think that having the cable right on the ground would make the outer
conduction more lossy, which would be positive. I suppose the best way to
test it is to lay out the 150' length and termination on the ground and run
a scan. Then raise it up five or six feet and redo the scan and see if
there is a difference. When I have some time, I will...
And this to anyone - this discussion has thus far been oriented
mainly toward stray RF, and the context has suggested stray
broadcast RF. How would the use of CAT-5 as discussed handle
electrical noise such as radiated TVI or power transformer
emissions, etc. ?
At my house it made a very minimal difference. The location of the antenna
itself was the important thing. Indoor antennas are essentially useless
except to monitor locals. Putting the antenna in the yard as far from
anything conductive does help, though the signal ingress from the cable
itself is an issue. One of these days I'll get around to putting one of the
ferrite loops or a vertical on the top of my tower. In the past I found a
20' vertical on a tower top made a very useful omnidirectional antenna. In
Providence at Brown University I did that on top of a 50' tower on a three
story building. I often heard some very distant stations such as WPRA-990
in Puerto Rico. Inside that building only the local AMs could be heard.
Even the tuned loop antenna for a local 790 EAS station to monitor wasn't
100% clear. Their transmitter site was maybe two miles away.
Another thing I may try some time is to frequency shift the whole AM band up
to around TV channel 3 or 4 at a distant spot. Run it through a cable, then
shift it back down to the AM band. That in itself would pretty much remove
any noise picked up on the way in.
Craig Healy
Providence, RI
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