"Darrell Bellerive" wrote in message
oups.com...
From what I have read there seem to be two common types of choke
baluns
employed at 146 MHz, the coiled coax balun and the W2DU type with
ferrite beads over the coax. Looks like other types of baluns such
as
the sleeve balun or a Guanella toroidal balun could also be used.

Other than the obvious restrictions imposed by physical mounting
arrangements, what are the advantages and disadvantages of each
type.

There seems to be considerable variation in the design of coiled
coax
baluns, with most designers advocating a few turns of coax with a
diameter of 3 to 8 inches. One designer was convinced that anything
over 3/4 of an inch would not be functional at VHF frequencies.
Others
maintain that the coil of coax should be wound on a core keeping the
turns aligned, while others simply coil the coax up and tape it
together. Some recommend one coax width of air between turns.

With regard to ferrite beads on the coax type of balun, how many
ferrite beads of what type are most effective? Some advocate that
another set of ferrite beads be placed at a point below the
feedpoint.

Seems there is lots of latitude in construction of these types of
baluns. Are they really this forgiving, or are there a lot of less
than
full effective balun designs?

I'm trying to decide what is the best option for me, and am confused
at
all the variations.

Darrell
VA7TO
======================================

The first thing to do is define precisely what you want the choke
balun to do and why. Then you might be getting somewhere.

If you don't know, you don't need one. Then you can forget and stop
worrying about it.