[Mich VHF UHF Society] 6m yagi issues; looking for 1.2/2.4g antennas

[Patrick Thomas]

Hi all,

When I put my m2 6m3 up for the June contest, I encountered needle-pinning SWR on the rig SWR meter... further checking showed the resonant frequency had moved up to ~60 MHz.  Fiddling with coax and antenna fittings - and even the setscrews on the shorting bars - resulted in no improvement.

A couple days after the contest I went back out there, unhooked the balun F connectors, cleaned everything out with alcohol, put it back together, went inside, and voila... worked like a champ.

Fast forward to a few days ago when we had stations from Japan (!?!?) audible on 6m, and sure enough, back to 5+:1 SWR.

Is anyone aware of something else to check on these antennas?  Figured I would ask this group before going back to ask tech support or ripping things apart.  I didn't notice any evidence of corrosion around the F connector and everything inside when I was cleaning looked like it had never seen the light of day since being assembled.  There is a bit of "patina" on the aluminum parts, but since it was working great with those same elements (like consistently fine with no evidence of intermittent failure for a few days), I'm a bit at a loss.  Rotation position also doesn't matter.

One of the set screws unfortunately did have the allen slot strip out... it is very tiny (1/16" or so?) and is in a hole not a whole lot bigger than that.. not sure if they make screw extractors or helicoils or whatever in such small sizes but again maybe you guys know... or maybe I should just re-tap it for a larger setscrew?

Also if there's anyone near (or willing to be near) the Novi area who has a directional 23cm or 13cm antenna they're looking to get rid of, please let me know.  Actually I would be interested in dish feeds too as it's just a matter of time until I get new mesh into the 8' C-band dish I have in the yard... but thinking more like yagi or corner reflector in this case.  Something I can bring up the hill with me for the UHF contest in August which is (sadly) only "a few weeks" away!

Thanks!

Pat
KB8DGC