Larry,
Congrats on the move! What follows is personal experience and may not be the same for everyone. I have had very poor luck looping the coax out the back of the antenna. I believe it is because I wound up with a conductor "flapping" around in the breeze close to the antenna yielding unpredictable results. What has worked best for me is to run the coax back down the boom of the antenna and then away from the antenna (at a right angle) at the crossboom. This only seems to work with the antenna in the "X" patern and fails miserably in the "+" pattern. There are also places along the boom to avoid when doing this (multiples of 1/2 wavelength).
Usually when I have had a problem like you are describing it has been a feedline/connector issue. It never hurts to make a complete check of that. I am also assuming you are rotating the "flexible" version of LMR-400.
The 436CP30 is a great antenna (nicer than any I've ever had), you hear lots of them on the birds and it should be more than enough for horizon to horizon coverage.
73 and Let us know what you find! Joe kk0sd
-----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
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I would do as Stan first suggested and make sure you are hearing terrestrial stations before getting into the real diagnostics.
Good luck
Craig N6RSX
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gary "Joe" Mayfield Sent: Tuesday, November 30, 2010 4:58 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: UHF antenna help
Larry,
Congrats on the move! What follows is personal experience and may not be the same for everyone. I have had very poor luck looping the coax out the back of the antenna. I believe it is because I wound up with a conductor "flapping" around in the breeze close to the antenna yielding unpredictable results. What has worked best for me is to run the coax back down the boom of the antenna and then away from the antenna (at a right angle) at the crossboom. This only seems to work with the antenna in the "X" patern and fails miserably in the "+" pattern. There are also places along the boom to avoid when doing this (multiples of 1/2 wavelength).
Usually when I have had a problem like you are describing it has been a feedline/connector issue. It never hurts to make a complete check of that. I am also assuming you are rotating the "flexible" version of LMR-400.
The 436CP30 is a great antenna (nicer than any I've ever had), you hear lots of them on the birds and it should be more than enough for horizon to horizon coverage.
73 and Let us know what you find! Joe kk0sd
-----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
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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participants (2)
-
D. Craig Fox -
Gary "Joe" Mayfield