[TowerTalk] 50:75 ohm transformation (LONG)

[Pete Smith]

Chad wrote: (much detail deleted)...

>
>So, bottom line:
>If you're using 10M and your run is short, go ahead and try to use
>the half-wave multiple.  If your run is long, you better think twice.

Ah ... that's the quantitative data I was lacking.  Thanks Chad!  W3LPL had
warned me about the same phenomenon on 10, emphasizing both the wide
frequency range and the likelihood that the load would be reactive for most
of it.  I figured that, at worst, I'd be adding UNUNs. In my case they
turned out to be unnecessary.  I'm using about 230 ft of 75 ohm, then 95
feet of 50 ohm, up to the feedpoint.  My 2:1 SWR bandwidth is over 1.5 MHz.
 Lucky?  Maybe.  Or maybe I have losses somewhere that are broadening the
bandwidth, but aside from the normal loss in matched RG-213, what I measure
in the hardline is about nominal.

I guess one consideration is how long is too long...

73,  Pete N4ZR
Loud is good


--
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