On Sat, 12 May 2007 19:25:22 -0500, Mike Coslo wrote:

wrote in news:1178935164.295223.69320
@o5g2000hsb.googlegroups.com:

Can the 20m, 75ohm matching stub perform double duty as a common mode
choke?

ie: will it hurt if i wind the stub around something like 4" PVC?

Best thing to do is try it and let us know your results. I would
guess that it might have some small effect on the match. In my own case,
there really isn't a good place to put the coil near the antenna, so a
choke is better right before entering the house.

- Mike -

I eneded up making a new 20m stub out of RG-6 and wrapped 11 turns onto
some 4" PVC. I then mounted this to the feed point of the antenna.

http://teh.3leggedcat.com/ham/matching-stub.jpg

I made a similar coil at work, where I have access to better test
equipment, and if I did the measurements correctly, the choke peaks right
at the 20m band.

As for the rest of bands, the measurements appear to be normal for this
antenna. Approx 80kHz of 80m, 250kHz of 40m, and full band on 30/20/15
and 10 with SWR 1.5.

An added bonus might be that the SWR on 12m is 1.3, so it looks like I
have a HF7V now.

--Teh