Larry,
A couple of others things to check after working through all the other great suggestions.
You did not mention how you moved it. Assuming you only broke it down to the boom sections, are the various phasing cables still good? There are a couple of places where you have to pull them very tight, and with a sharp bend, to get them to fit. Those could use checking. As someone else noted, the SWR is not that high, and if one of those were broken, I would expect things to be more obvious.
The other area to check is the aluminum blocks which are the folded dipole feeds. About two years ago, I noticed that rear driven element was slightly but obviously crooked. The SWR measured by my Bird was about 1.8:1. I brought it inside and opened the aluminum box. Sure enough, that was the problem. One of the connections was loose, and the element was not internally supported or connected. (Best theory is a bird flew into it. I have had 2 other such incidents over the years, complete with blood and feathers, and in one case a dead hawk.) However, what surprised and appalled me was that the broken connection was a solder bridge, and a very obvious one! We are talking something which even MFJ "quality control" would reject. However, it would have been possible for the mechanical connection to be good, with the electrical connection still bad. I am thinking there is a possibility, slight though it is, that yours might have gotten bumped in transport. It is not robust at all. I repaired the connection better than new, and all is well. The next time I take down the antennas, I will crack them all open and check.
Something to check if all the probable stuff fails.
73s es gud luck!
Alan WA4SCA
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of larry Sent: Monday, November 29, 2010 7:14 PM To: amsat-bb@amsat.org Subject: [amsat-bb] UHF antenna help
Good evening,
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 your opinion.
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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