Topband
[Top] [All Lists]

Topband: binocular matching transformers

To: Topband@contesting.com
Subject: Topband: binocular matching transformers
From: Pete Smith N4ZR <n4zr@contesting.com>
Date: Sun, 24 Mar 2013 15:48:54 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Please have mercy on a history major...

I'm trying to wind a binoocular core matching transformer for 75-ohm coax to a BOG with (for a start) 270 ohms of terminating resistance. I figure that is a 4:1 stepdown, which should require a turns ratio of 2:1. Initially I wound a #73 core with identical windings, 3 passes each.

I put this on the output of my MFJ-259 with a 270-ohm resistance on the secondary. To my surprise the MFJ read 135 ohms, not 270 as I would have expected. Is this not appropriate as a way of measuring the transformer? Should I just go ahead and wind 2:1, and if so, how many turns/passes are appropriate for 160M?

--

73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

All good topband ops know fine whiskey is a daylight beverage.
_________________
Topband Reflector

<Prev in Thread] Current Thread [Next in Thread>