Hello Ted,
I have gone to using a 1.5:1 UNUN at each end of my 550 ft. length of 3/4 inch
CATV hardline and it works fine. If you have an antenna tuned to 50 ohms fed
with any length of 50 ohms going into a 1.5:1 UNUN into any length of 75 ohm
hardline and again into an UNUN into any length of 50 ohm line to your
transceiver, things will be fine because you will have a flat line all the way.
73/Mike, N7ML
Ted Boerkamp wrote:
> Hello to all..... I spent the past summer putting up a new tower with
> a TH7 at the top and various wire antennas to complete the coverage.
> However, due to time/weather constraints I was forced to use a 200ft
> run of rg213 to feed the relay box at the tower....my intent is to replace
> this feed with some 75 ohm CATV cable that I have acquired, sometime
> in the spring....my question...I have read alot here about "tuning/pruning"
> the CATV to resonant lengths...if i were to use 50:75 ratio Ununs at each
> end of the run, do i still have to worry about "pruning" the length of this
> feed??(will any direct length do?) does anyone else use Ununs in their
> setups?? How do they work for you?? Based on the standard formula for
> calculating the resonant length, and on the distance from the shack to
> the tower, i either end up with a length too short or with an extra long
> length which has to be coiled up somewhere out of the way....I guess
> I am just checking out all of my possibilities...
> Any help would be appreciated.....thanks es 73 Ted VE3SS
>
> --
> FAQ on WWW: http://www.contesting.com/towertalkfaq.html
> Submissions: towertalk@contesting.com
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: owner-towertalk@contesting.com
> Search: http://www.contesting.com/km9p/search.htm
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|