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  #31   Report Post  
Old February 11th 06, 03:46 AM posted to rec.radio.shortwave,alt.home.repair
Tony Calguire
 
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Default Want to replace old flat tv cable with better coax.

jg wrote:

Funny that you mention that. I have a linux box that I've setup with
MythTV. I've also tried Freevo.



Not to get too far off-topic, but how's that working out for you? I've
always been intrigued by the idea of MythTV.
  #32   Report Post  
Old February 12th 06, 08:02 PM posted to rec.radio.shortwave,alt.home.repair
mm
 
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Default Want to replace old flat tv cable with better coax.

On Sun, 12 Feb 2006 13:25:44 GMT, "Ralph Mowery"
wrote:


"Tony Hwang" wrote in message
news:meBHf.602959$ki.30465@pd7tw2no...
jg wrote:


Hi,
Twin lead also has better quality foam ones not the skinny twirly kind.
Coiling up extra coax is not a good idea it can act like RF choke and
could lower signal level.
Tony


Coiling up extra coax wil not make it like a RF choke and will not lower the
signal level. As long as the coil diameter is large enough that the center
conductor does not cut into the iner insulation and short to the shield,
nothing on the outside of the coax will affect the strength of the signal.
The signal is carried on the inside of the outer shield. Coil up all the
extra you want. One thing that will affect the signal is if you have way
too much coiled up (like 20 or more feet) is the extra loss in the length of
coax. YOu will get the same ammount of loss if it is coiled or just ran in
a line.

If you are transmitting , coiling up the coax may have a benifit as it will
act as a choke and keep the transmitted rf that is coupled from the antenna


You sound like you know what you're talking about, but one thing gets
me. Here you say it will act as a choke and at the start of the
previous paragraph you say it won't. Why does transmission have a
different result from reception, or is there some other difference?

from getting back to the transmitter. Discussion on this is beyond the TV
application and not needed here.




Remove NOPSAM to email me. Please let
me know if you have posted also.
  #33   Report Post  
Old February 12th 06, 08:54 PM posted to rec.radio.shortwave,alt.home.repair
 
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Default Want to replace old flat tv cable with better coax.

That's it.
http://salestores.com/chma428bouhf.html

  #34   Report Post  
Old February 12th 06, 09:55 PM posted to rec.radio.shortwave,alt.home.repair
Ralph Mowery
 
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Default Want to replace old flat tv cable with better coax.


"mm" wrote in message
...
On Sun, 12 Feb 2006 13:25:44 GMT, "Ralph Mowery"
wrote:


"Tony Hwang" wrote in message
news:meBHf.602959$ki.30465@pd7tw2no...
jg wrote:


Hi,
Twin lead also has better quality foam ones not the skinny twirly kind.
Coiling up extra coax is not a good idea it can act like RF choke and
could lower signal level.
Tony


Coiling up extra coax wil not make it like a RF choke and will not lower

the
signal level. As long as the coil diameter is large enough that the

center
conductor does not cut into the iner insulation and short to the shield,
nothing on the outside of the coax will affect the strength of the

signal.
The signal is carried on the inside of the outer shield. Coil up all the
extra you want. One thing that will affect the signal is if you have way
too much coiled up (like 20 or more feet) is the extra loss in the length

of
coax. YOu will get the same ammount of loss if it is coiled or just ran

in
a line.

If you are transmitting , coiling up the coax may have a benifit as it

will
act as a choke and keep the transmitted rf that is coupled from the

antenna

You sound like you know what you're talking about, but one thing gets
me. Here you say it will act as a choke and at the start of the
previous paragraph you say it won't. Why does transmission have a
different result from reception, or is there some other difference?

from getting back to the transmitter. Discussion on this is beyond the

TV
application and not needed here.


I have been a ham radio operator for over 30 years and at one time held a
first class phone license that was good for the comercial radio repair.

When receiving the signal comes from the antenna it comes down on the
outside of the inner wire and the inside of the outer sheild. Unlike
Direct current which uses all the wire area, as the frequency goes up, the
signal only uses part of the area. That is a copper tube can carry just as
much signal as a solid wire the same diameter. Large coax (usually called
hardline) is often made this way. There is nothing useful on the outside of
the shield of the coax. In otherwords everything from the receiving
antenna is on the inside of the coax and coiling it up has no effect .

When transmiting it is possiable that some of the signal from the antenna
will couple or be introduced on the outside of the coax. This unwanted
signal will come back down the coax on the outside of the shield and can
cause problems with the transmitter and other electronics in the house. If
the coax is wound in a coil it may choke off this unwanted signal. The coil
is usually placed outside the house .


  #35   Report Post  
Old February 13th 06, 09:08 PM posted to rec.radio.shortwave,alt.home.repair
jg
 
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Default Want to replace old flat tv cable with better coax.

Ok, so is it possible to have both my current antenna pointed in one
direction (minus the UHF section) and use this new antenna pointed in a
different direction? Then just combine the signal? This would give me
the best of both world w/o the need for a rotor.



  #36   Report Post  
Old February 13th 06, 09:10 PM posted to rec.radio.shortwave,alt.home.repair
jg
 
Posts: n/a
Default Want to replace old flat tv cable with better coax.


You seem to know a lot. Here's a question, if my mast is well grounded
(buried a few feet) do I still need to ground the coax before it enters
the house? The way I see it, the mast will dissipate any charge on the
antenna? Yes?

  #37   Report Post  
Old February 14th 06, 05:15 PM posted to rec.radio.shortwave,alt.home.repair
Mark Zenier
 
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Default Want to replace old flat tv cable with better coax.

In article .com,
jg wrote:
Ok, so is it possible to have both my current antenna pointed in one
direction (minus the UHF section) and use this new antenna pointed in a
different direction? Then just combine the signal? This would give me
the best of both world w/o the need for a rotor.


Sure. Back in the dark ages, when the UHF channels went up to Channel
83, TV sets didn't have a combined antenna input, instead they had
two (usually 300 ohm) inputs, one for each band. To save cable,
VHF/UHF splitter/combiners were used if you had an all band antenna.
They're bidirectional, the same unit can be used either way. So you
can run two antennas into the one cable.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

  #38   Report Post  
Old February 14th 06, 09:13 PM posted to rec.radio.shortwave,alt.home.repair
jg
 
Posts: n/a
Default Want to replace old flat tv cable with better coax.

Thanx to all who replied and helped out. I've installed a balun
tranformer at the antenna and I've replaced the entire run with RJ6
coax cable. Picture quality increased drastically on all channels.
I've got my antenna pointing 206 degrees yet I can still pick up
channels 29 (103 degrees) and 19 (143 degrees.) (My antenna's fault
I'm sure.) At any rate the local stations (Sacramento) all come in
super clear, so I'll leave it as it is.

Thanx again.

  #39   Report Post  
Old February 17th 06, 01:39 AM posted to rec.radio.shortwave,alt.home.repair
Brian O
 
Posts: n/a
Default Want to replace old flat tv cable with better coax.


"jg" wrote in message
oups.com...
Thanx to all who replied and helped out. I've installed a balun
tranformer at the antenna and I've replaced the entire run with RJ6
coax cable. Picture quality increased drastically on all channels.
I've got my antenna pointing 206 degrees yet I can still pick up
channels 29 (103 degrees) and 19 (143 degrees.) (My antenna's fault
I'm sure.) At any rate the local stations (Sacramento) all come in
super clear, so I'll leave it as it is.

Thanx again.

If you ever get the urge, buy a good long distance antenna and put a rotor
on it and see what you get!
B


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