"Richard Clark" wrote in message
...
On Sun, 14 Dec 2008 23:20:10 -0000, "christofire"
wrote:

50 ohm common point with no need for a balun.
If the drive-points of the Yagis are equipped with adequate baluns

And your question is about....?

73's
Richard Clark, KB7QHC


Is this a quiz?

I simply questioned your statement that the very common arrangement of
star-point and transformer, implemented in co-axial line, should be 'a
common mode nightmare' as you put it. The middle portion of the diagram
(http://www.vk1od.net:80/lost/Fig6.png) posted at the beginning of this
thread shows baluns on the drive points of the dipoles and nowadays Yagi
antennas for amateur as well as professional use appear to be sold more
often with integral baluns. Co-axial feeders always interact to some extent
on account of their outer conductors being in the vicinity of the antenna(s)
but there are simple steps that can be taken to minimise this.

However, I concede there may be some reason to want to combine/power-split
using balanced line but ultimately it will need to be connected to a
co-axial line - if the intention is to achieve this without use of a balun
then I wonder if this would be more of a 'nightmare'.

Chris