[TowerTalk] Building a W6NL Moxon 40 Meter Beam.

[Steve Hunt]

Unlike some more conventional Yagis the feedpoint impedance at the 
centre of the Moxon Driven element is very close to 50 Ohms; you just 
need a Common-Mode choke at the feedpoint to reduce the likelihood of 
current flowing along the outside surface of the coax braid.

Steve G3TXQ




On 03/08/2014 21:06, L L bahr wrote:
> Also, the feed point on all the versions I have looked at couple an RF choke right to the center point area of the Director.  When I built a couple plain Yagi antennas, I used a Gamma Match or T match thus tapping the Director element at a 50 ohm point rather then at say at a 15 ohm point or so right at the center of the director.  Why is this not done on the W6NL building examples?  Is it because they think and hope the RF balun choke is going to keep the mismatch SWR in check?  Can anyone explain this to me? I'm not sure, but I suspect the impedance right at the center of the Director is not 50 ohms or even close to being 50 ohms.