On Jan 18, 10:32*pm, Jeff Liebermann wrote:
On Sat, 17 Jan 2009 12:44:05 -0800 (PST), JIMMIE

wrote:
I was considering using a TV type 4:1 balun on 2 meters. Does anyone
know how much power these can handle? I remember a guy doing this when
I was a teenager(long ago) but I think the baluns were built a little
stouter back then than they are now.

May I suggest using a coaxial cable 4:1 balun instead of ferrite core
type. *A 1/2 wave electrical length of coax cable, some soldering, and
you're done. *For just 2 meters, the bandwidth is just fine and the
loss is no more than that of the coax cable. *For low power, small
diameter RG-174 type coax is fine. *I use 4:1 coax baluns for matching
300 ohm folded dipole antennas:
http://users.belgacom.net/hamradio/schemas/14balun.gif

The common TV balun has two xfomers inside, which are sometimes
combined on a single core. *See schematics at:
http://members.tripod.com/rclindia/trans.html
http://www.electronics-tutorials.com/basics/baluns.htm

However, if size is an issue, I guess the coax balun is a bit large.
For just 2 meters, the ferrite core is not necessary. *Just find a
block of PTFE (Teflon) or plastic, and drill it to resemble the TV
balun core, use 2 PTFE toroid cores (if you can find them), or
simulate a torroid with a stack of nylon washers. *Then wind the 2
pairs of 2 wires through the holes and bring out the connections.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

Jeff, Apparently TV matching transformers used to be air core and
their use was quite common on 6 and 2 meter antennas.I knew the ones
built into the old tuners were but I hadnt thought the old line
transformers also being air core.They were per some of the locals on
2m repeater. If they aare the ones I am thinking of(big fat ones) I
have a few at home.

Jimmie