[TowerTalk] Cable TV hardline question

[Bob Pack, NX5M]

Build 1/12th wave coaxial transformers on each end.  Easily done if you are 
not happy with the swr.  My last install for a 20m stack was almost 300 
feet of the 3/4" catv with trannys on each end.  Tested into a dummy load I 
could find no swr to speak of.....and the swr after all the antennas were 
up in my worst case combination is no higher than 1.3:1.  I might add that 
I am also using 1/2" catv from the phasing/switchbox to the tail of RG213 
connected to the antennas.

GL
Bob NX5M
 
On Fri, 29 Oct 2004 11:33:28 -0400, Tim Holmes <W8TAH at Zoominternet.net> 
wrote :

> Yeah, thats what I was worrying about-- If anyone has any good 
> suggestions, I would love to hear them,  I hate to have this stuff just 
> sitting around, not doing anything.
> 
> Tim
> 
> >I would be concerned also, since the cable can cause an SWR
> >of over 2:1 at the radio.
> >Most VHF and UHF radios do not tolerate such a high SWR this
> >very well.
> >
> >What you can do is build a transformer using lengths of 50
> >and 75 ohm cable mixed. It is pretty tricky to do this at
> >UHF, but it can be done if you have the test gear and are
> >careful. I don't have references, but I'd bet someone else
> >does. The devices are called non-synchronous transformers.
> >
> >I certainly look into matching the cable at VHF or UHF, not
> >because of cable loss but because of bandwidth and impedance
> >problems at the radio. A 2:1 SWR is not good for most
> >radios.
> >
> >73 Tom
> >
> >  
> >
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