On Wed, 01 Mar 2006 15:09:12 -0500, dxAce
wrote:



Bob Miller wrote:

A balun won't give you a decent match except on the single frequency
it is designed for. That's one problem you run into, putting a balun
on a multi-band or multi-frequency antenna.

Single frequency?

dxAce
Michigan
USA


At different frequencies the antenna will have different impedances
and the balun may or may not match.

bob
k5qwg

In article ,
Bob Miller wrote:

On Wed, 01 Mar 2006 15:09:12 -0500, dxAce
wrote:



Bob Miller wrote:

A balun won't give you a decent match except on the single
frequency it is designed for. That's one problem you run into,
putting a balun on a multi-band or multi-frequency antenna.

Single frequency?

dxAce Michigan USA


At different frequencies the antenna will have different impedances
and the balun may or may not match.

Antenna reactance and impedance are two different things. The antenna
impedance in this case is a characteristic of the single wire or a
dipole. The first case is hundreds of ohms and the second about 72
ohms. And like you stated in another post in the thread he does not
need a BALUN for the dipole.

The purpose of a BALUN, UNUN or other types of impedance matching
device is to match the characteristic impedance of the antenna to the
transmission line, which in this case is the coax.

The impedance transformers do not tune the antenna and don't deal with
antenna reactance to a certain frequency.

It seems people make this mistake all the time.

--
Telamon
Ventura, California