Are you looking for the raw equations, a hand calculation method, or a
computer program to solve the problem?
For the latter, get a copy of the (free) transmission line spreadsheet
XLZIZL from AC6LA. It's an Excel spreadsheet (with a whole pile of VBA
included) that can do what you want, and more. It's quite easy to use, and
has appropriate hooks for solving things. Of particular interest is that
there's a fairly complete list of various transmission line characteristics
included.
If you're looking for either of the first two, give some more details, and I
can probably help you find it.
The equations are in the ARRL Antenna book, and maybe the handbook, but I
don't recall if either has a "cookbook" solution method to find the lengths.
..)
I would imagine that most techniques for solving the problem you describe
are iterative in some way (whether by using Excel's solver, finding a curve
on a Smith chart, etc.), although, with some appropriate simplifying
assumptions (i.e. lossless lines), you can probably come up with an analytic
equation using inverse hyperbolic funcitons.
----- Original Message -----
From: "K4SB" <k4sb@bellsouth.net>
To: <towertalk@contesting.com>
Sent: Sunday, April 24, 2005 8:45 AM
Subject: Re: [TowerTalk] Previous Feb 74 HR magazine
> Guys, I now know the above subject magazine is not the correct one.
> The author's call was OD5CG, and it may have appeared in 73 magazine.
>
> Basically, the article gave a rather complicated set of formulas and
> after your input, would give you a matching solution.
>
> For instance, if you had an antenna with a 145 -j46 load, the output
> would tell you to insert an electrical length of X degrees of a
> different impedance feed line ( including open wire in a coax system )
> at a point Y measured from the 50 ohm connection at the antenna. Nice
> thing about the thing is that it takes reactance into account.
>
> For example, for the above, it might say measure 7' back from the
> load, cut the 50 ohm line at that point, insert 4.75' of RG11 and then
> transition back to the 50 ohm line.
>
> The response from "towertalkers" has been fantastic!! But no luck yet.
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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