Here's what I do:
Take a 500 Ohm, 2W linear taper carbon potentiometer wired as a rheostat
(center and one end terminal shorted together) and wire it across the
"unknown" terminals of the balun using the shortest possible, low inductance
wiring (I usually just use 1/2" wide copper strap, each strap being about an
inch long or so -- long enough to reach the balun terminals).
Plug MFJ259B into the "coax" (presumably 50 Ohm) port of the balun, and tune
it for a low frequency like 2 MHz. Turn the potentiometer for a dip in SWR
read by the 259B. If it dips all the way down to 1:1, great.
Now, disconnect the potentiometer leads from the balun and measure DC
resistance with an Ohmmeter. Whatever it reads is the secondary impedance
of the balun when its primary is connected to 50 Ohms.
Works like a charm. If you have the 259B, total cost of the setup is about
$2, for the potentiometer.
WB2WIK/6
"Success is the ability to go from failure to failure with no loss of
enthusiasm." -Winston Churchill
> -----Original Message-----
> From: Van Fair [SMTP:vfair@innova.net]
> Sent: Friday, February 07, 2003 11:00 AM
> To: towertalk@contesting.com
> Subject: [TowerTalk] Balun for Carolina Windom 160
>
> 9 months ago I purchased and installed a carolina windom 160. I found it
> to be of little value on 160 and 80 and worth even less on the higher
> bands. So I took it down to salvage the wire and Balun.
>
> Balun is unmarked as to what it is and Radio Works refuses to tell me.
> They say it is proprietary info. I know it is 52 ohm in. I suspect it is a
> 4 to 1.
>
> Anyone know how to tell the balun output using and MFJ 259 antenna
> analyzer. I read how to do it somewhere but cant remember where or how.
>
> Thanks and 73
> Van W4GIW
> _______________________________________________
>
> 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.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
|