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

I was rummaging through my mobil junk er toolbox and came across an
old package of air core TV baluns. These date back to the day when
TVs were usually fed with twin lead. Tuesday I may be able to get to
some test equipment to check out the losses on those. Gee getting to
spend a 3day weekend on the road is such fun.

Jimmie