I put up a old 8' channel master with a quad leg feedhorn co-rotor 2+ with very good quality lnb's(cal-amps). Does anyone know what the correct F/D of these dishes are? I get very strong signal on the west side of the arc with the F/D set at 38, south and east suffers at this F/D. if I set the F/D at 36 or 34 my south and east side of the arc gets much better and the west starts to fade. Lifting the dish up or pushing it down on all sat's lowers signal quality and this dish has no declination adjustment. Any suggestions? I'm peaking the dish using KU sat's, my c-band signals are all great across the arc. Thanks for your help.
8' channel master quad leg feed alignment help.
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Here is the formula to determine the F/D. You may also be a tiny bit off south, turn your dish on your mounting pole a tiny bit east/west and check your signal strength.
I don't understand this dish. I first got all c-band satellites in very solid signal, but the Ku suffered. Now I re-peaked using Ku Sat's only and got all Ku Sat's from AMC6 to AMC21 locked with very good signal and went back to the c-band sat's and most of them are gone with no signal strength. Good signal on AMC9Ku but nothing on AMC9C? What is going on with this, I figured peak the Ku's and the C's should be perfect. any ideas please?
with my dual band mdx741 i peak on c band and i have to accept what k band is there. sometimes i have to rotate the lnb slightly to peak on the k band after the c band is peaked. hope this helps. charlie
I do separate sat list for ku and cband.
sometimes ku might be off 1/2 a degree from cband on the same sat.
is what it is with my 741 LNB
sometimes ku might be off 1/2 a degree from cband on the same sat.
is what it is with my 741 LNB
I'm using a co-rotor 2+ so I can adjust polarity and that's not it. I can't even bring in signals on c-band now, but the ku is very good and strong on all birds. Like elevation is way off, but if I peak c-band then no Ku.
Make sure the feed is perfectly centered, and aiming at the dead center of the dish.
The formulas will get you "into the ball park" but can be a fair bit off of optimum. And yes, the dual band feeds are usually a bit of a trade-off in performance. So some tweaking is almost always required. Takes patience tweaking this and that. Keep notes of what you do and if it improves or degrades reception. I'd only do, or undo, one tweak at a time, for if two are done simultaneously, what did what?
As to "No declination adjustment" [???] I thought the only manufacturer that didn't incorporate that was Birdview. A couple of pictures maybe. We like pictures. Maybe someone with experience with the same model dish chimes in.
The formulas will get you "into the ball park" but can be a fair bit off of optimum. And yes, the dual band feeds are usually a bit of a trade-off in performance. So some tweaking is almost always required. Takes patience tweaking this and that. Keep notes of what you do and if it improves or degrades reception. I'd only do, or undo, one tweak at a time, for if two are done simultaneously, what did what?
As to "No declination adjustment" [???] I thought the only manufacturer that didn't incorporate that was Birdview. A couple of pictures maybe. We like pictures. Maybe someone with experience with the same model dish chimes in.
I will after vacation, I leave on Sat. don't think I'll get the picture taken and uploaded by then. After the 24th. Thanks.
You know what? I fried my diseqc switch doing dish alignment. Switching from my meter, to my satellite receiver while hot. I swapped out the diseqc switch and everything seems fine now. Just need to fine tune the F/D of the feedhorn a little. Thanks.
Yep it's the fiberglass one and I get the best signal strength at 38 My focal gauge on the side of the feedhorn only goes to .38 Would this be close enough to .385 or do I need to go past my last mark? I like to stop at .38 because there is a gauge line every little bit around the feedhorn for perfect alignment. Thanks for your help. I was hoping someone could help me on this one.
The markings on the side of the feedhorn is for f/d (focal length to diameter ratio). The f/d of this dish is .40 and the focal length is 38 and a half inches. The way I would do it is set the mouth of the feedhorn to protrude past the first scalar ring by about 3/10 of an inch. Measure the focal length from the dish face to the mouth of the feedhorn and see how close it is to 38 1/4 inches. The focal length is usually measured 1/4 inch inside the mouth of the feedhorn.
I found 2 Channel Master SMC dishes in my hunting this year. The first 2 pics are from an early version dish (it says Channel Master TVRO on the dish) that the declination is done with spacer plates. the second two pics are from a later version where the declination is done with the backplate. See the link for the manual I uploaded.
Channel Master SMC Fiberglass Antenna - Downloads - SatelliteGuys - America's Satellite & Home Theater Technology Information Source!
hope this helps
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That's how this one is too. Declination is done with spacer plates. I don't have any other size spacer plates, so I'll have to leave it as it was originally set up for declination. I only moved the dish about 25 miles from where it was set up. I hope it's close enough on the declination side. Thanks for your help. Chad
You've helped me out a ton! I thank you. I got home and measured and I was only at like 37 3/4" from the center of the dish. So I moved the feed to .40(and yes I found out there is a .40 on there after all) and now I got a 38 1/4" to the edge of the feedhorn from the center of the dish and am now getting perfect signal strength on AMC 9ku watching some Basketball. Thanks for your help! Chad
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