[amsat-bb] Re: UHF antenna help
Mark L. Hammond
marklhammond at gmail.com
Tue Nov 30 05:02:28 PST 2010
Have you determined that your pre-amp is still working?? I'd do that first.
I have found the 436CP30 to be a good antenna.
At 08:14 PM 11/29/2010 -0500, larry wrote:
> Name here is Larry, N1MIW. I recently moved to a better (higher) QTH and
>finally got around to setting up the satellite station "almost" like it used
>to be, but am experiencing some reception difficulties on UHF. I'm hoping
>someone out here can help me diagnose what I'm doing wrong, or what the
>problem is. I am using a Yaesu FT-847 which is computer controlled, as well
>as the Yaesu G-5400 rotator. The antennas are mounted on a solid fiberglass
>mast only ~17 feet off the ground, and fed with LMR-400. The frequencies are
>correct for the satellite I want to use.
> My problem is with the 436CP30 antenna. I cannot seem to find good
>results with it since my move - terrestrial or sat related. My SWR is around
>1.5:1 at 435MHz, and the polarity switch is working. I tried changing
>feedlines and removing the pre-amp, but I still cannot seem to make it work
>correctly. I am trying to receive SO-50 D/L, and VO-52 U/L, but both are
>just not working like I remember it being before the move. I don't have any
>broken or mis-aligned elements (that I noticed - I'll look again). The only
>thing I was looking into was instead of having it placed on the boom in a
>"+" pattern was making it an "x" pattern - would that make a difference? I
>don't remember hearing or reading about that anywhere, so I was looking for
> On a side note, what's your opinion of this antenna? Like I said, I used
>to have good luck with it, but I'm not sure what's different, except the new
>home. Should I get "horizon" to "horizon" coverage (plus or minus a few
>degrees)? Oh, I also looped the coax off the back like the manual states,
>but the improvement is very minimal. I checked the "jumpers" at the tuning
>box, and they seem OK too.
> I'm running out of ideas, and any guidance would be appreciated. Thanks &
>looking forward to working the birds again!
>73's... Larry N1MIW
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Mark L. Hammond [N8MH]
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