On 29 Nov 2005 06:52:04 -0800, wrote:


David wrote:
You can't send a MC phono signal 70' on co-ax either.
++++++++++++++++++++++++++++++++++
You mihgt find the story
at:http://broadcastengineering.com/mag/broadcasting_future_video_utp/
intersing.
It discribes using UTP (unshielded twisted pair) for video.


Mention is made of crosstalk.
For CAT5 cable 53dB of isolation at 4.2MHZ is acheived.
CAT6 gies 63dB at 4.2MHz.
Crostalk increases with frequency.

Another good refference that shows "failure" modes for twisted pair:
http://www.extron.com/technology/archive.asp?id=utptechnology

I have lost my bookmarks to a couple of links for coax cable "leakage"
and crosstalk specificitions. I will have to pull them from a backup
later this
week.

Why do you suppose that 99.99% of all CATV operations use coax for
the coper connections instead of twisted pair? Twisted pair is less
expensive,
so if it was "as good" as coax I suspect they would switch to it.

It has never been my contention that twisted and parallel balanced
pairs
have no place in the world. I just accept that while they do have many
usefull applicaitons, low level RF distribution isn't 'one of them.

By the way we are rolling out some component HDTV in house distribution
with CAT6 UTP. Looks pretty darn good after a 200' run. The CEO wanted
this and it was much cheaper to pull in good CAT6 then 4 coax cables.

Terry

I think the context is shortwave radio.

David wrote:

I think the context is shortwave radio.
+++++++++++++++++
I was tryihng to show the isolation of good quality UTP is around 63dB.
63dB is very good for a 1V video(RF from 0~5MHz), not so very good
for antena supplied RF.

Not near quite enough for my location.

Feel free to use any cable you wish.

I was trying to help newbies avoid the mistakes that I had already
made.

Terry

On 29 Nov 2005 07:34:07 -0800, wrote:


David wrote:

I think the context is shortwave radio.
+++++++++++++++++
I was tryihng to show the isolation of good quality UTP is around 63dB.
63dB is very good for a 1V video(RF from 0~5MHz), not so very good
for antena supplied RF.

Not near quite enough for my location.

Feel free to use any cable you wish.

I was trying to help newbies avoid the mistakes that I had already
made.

Terry

You lose me with all those numbers. I just look for symmetrical
bowties.

David wrote:
You lose me with all those numbers. I just look for symmetrical
bowties.
++++++++++++++++++++++++
Sorry I thought this news group was about Shortwave, receivers and
antennas.

A special sub-part of the hobby is antenna and feedline inter-reaction
and how to get the strongest, cleanest RF signal from the antenna to
the
receiver.

I had hoped that we were having a somewhat serious fact based
conversation.

Sad to see how wrong I was.

Anyway, you are the very first person I have killfiled.
I had wrongly assumed that inpiste of your repeated OT politcal
comments
that you were a serious SWL. Sorry to waste our time.

Terry

On 29 Nov 2005 13:25:38 -0800, wrote:

David wrote:
You lose me with all those numbers. I just look for symmetrical
bowties.
++++++++++++++++++++++++
Sorry I thought this news group was about Shortwave, receivers and
antennas.

A special sub-part of the hobby is antenna and feedline inter-reaction
and how to get the strongest, cleanest RF signal from the antenna to
the
receiver.

I had hoped that we were having a somewhat serious fact based
conversation.

Sad to see how wrong I was.

Anyway, you are the very first person I have killfiled.
I had wrongly assumed that inpiste of your repeated OT politcal
comments
that you were a serious SWL. Sorry to waste our time.

Terry