Can't Align Top 10 7.5' Dish

[KJ6EO]

Hello and thanks for reading my post. I'm trying to align a Top 10 7.5' dish here in SoCal. I set the elevation angle and declination angle with a digital angle meter. My true south satellite here
is 119w Anik F3. I rotated the dish on the pole until I received a strong signal from Anik F3. Also, it's important to mention that the pole it's mounted on is perfectly vertical. Currently, I can get
signals down to 91W and up to maybe 131W. East of 91W I get nothing. So, even using the factory specified alignment data, I'm still not tracking the arc correctly. The problem is that if I try
to correct this problem, things even get worse. So, what I currently have seems to be the best the dish is capable of. Another thing I would like to mention is that the LNBF is installed correctly,
correct skew and F/D.

DISCUSSION:

I've aligned 6 or 7 C-Band dishes and I've never had a problem like this. Normally, I install the LNBF, set the F/D and skew, set the elevation angle, declination angle, true south, then sometimes a
slight adjustment of true south when I'm on a satellite at the bottom of the arc. This works every time, and I don't have any problems. All that I can assume is that there is something weird going
on like, the dish is worn out (excessive play), or it's damaged parabolically, or the quad mount isn't centered up correctly, etc. Visually however, it looks ok. They gave me 2 Titanium PLL LNBF's
to try out. Both had been out in the rain (water in the throat), so, I've ordered one of the new Titanium LNBF's that has the 5G filtering built in. I'll probably install the new LNBF in a couple days.
I think that both of the old LNBF's are bad because when I scanned 117W (having a hugely strong signal) I only got 30 channels and and 3 TP's. I should have got over a hundred channels and
maybe 35 TP's there.

IN CLOSING:

Any thoughts or suggestions that you might have would be appreciated. Once I have a known good LNBF, if I don't have better results, it might be time to get another dish.

 

[primestar31]

Likely, the lnbf isn't centered or squared to the dish where it should be. Or, if it's like mine was, check THIS: I'll take "Name that satellite" for $500 please! HELP!

 

[a33]

So, even using the factory specified alignment data, I'm still not tracking the arc correctly. The problem is that if I try
to correct this problem, things even get worse.

So, assuming you have set the dish optimal for 119W: did you check at 91W, what dish finger pushing increased the signal: up or down?

And the same question for 131W?

Greetz,
A33

 

[KJ6EO]

Thank you for your replies. At 91w, pulling up on the dish causes the signal to decrease. There is no change if I press down on the dish. Another check I did was to bring their receiver home and do a blind scan on 117w using my BUD. I got something like 50 TP's and 147 channels. This is what I would expect to get. So, this indicates that the receiver is good. Just for grins and giggles, I replaced the LNBF with a brand new one. The results were ... no difference. Again, I double checked the F/D and the Skew, all looks good there. This is the conclusion that I've come to. This is a 7.5' dish, a lot smaller than my 10'. There is an approximate 150' run of RG-6. So, I'm thinking that I need to install a L-Band Line Amp to boost the signal. I've never used an amplifier before between a receiver and a BUD. Will the L-Band Amp pass the 13/18vdc V/H switching voltage? Any guidance or comments you might have on this would be appreciated. Thank You!

 

[a33]

And the same question for 131W?

And what were the test results for this?


Re amplifier: an amplifier does not improve signal, alas, it just amplifies signal (and amplifies the noise, also)!
So when you have no problem with signal strength, it would be of no use (or even counterproductive).

If your 150' run of RG-6 is of good quality (pure copper core, and braid), I would guess no amplifier would be needed. With bad quality cable it might: Is reception near the dish, with a short cable, better than after the 150'?

As far as I know, an amplifier is made just for this use, and so passing 13/18vdc V/H switching voltage and 22kHz.

Greetz,
A33

 

[arlo]

Let's get a visualization going on here.
"At 91w, pulling up on the dish causes the signal to decrease. There is no change if I press down on the dish."
Looks like you have to lower your elevation or declination a touch.
A hint to assure that the feed is indeed aimed at the dead center of the dish is what I did.
See if you can find a couple of paint can tops that telescope into each other. One that can slip inside of the feed.
Then tape them together and grab a wood dowel or a fiberglass driveway marker. Drill a hole in the center of the caps and put the straight rod through. Then fit the cobbled pointer up to the feed. Careful to not disturb the probe(s). Aim your feed dead nuts at the dish center. Snug the fasteners.
Of course with the dish at its highest arc the 0 skew reference on the feed must point straight up. Fix it there.

Next go back to whatever sat (91W) and see if you get a signal. Lift up, press down on the dish. You need to be in the middle of signal loss and peaked with the elevation/declination adjustment.
Now you need to figure out tracking. Next sat. W in the arc. Is the dish still peaked for signal? Or does raising or lowering the dish rim make a difference.
Go out further West. Are you starting to have to lift/lower the rim a lot more to get signal peak?
Once you can get a pattern of how the dish is tracking. Check this out and get back to us.

 

[a33]

Let's get a visualization going on here.
"At 91w, pulling up on the dish causes the signal to decrease. There is no change if I press down on the dish."
Looks like you have to lower your elevation or declination a touch.

I think that is too early a conclusion, when you don't know the results of the test at 131W.
It might still be imperfect due south alignment.

So I'll await his answer....

Greetz,
A33

 

[KJ6EO]

Thanks for your suggestions. With the dish parked at 91W, I made a small adjustment to the declination angle. Now, as I either push UP or DOWN on the edge of the dish, the signal decrease's evenly both ways. While I was at 91W, I checked the True South Alignment by rotating the dish slightly back and forth. The strongest signal was achieved where I had previously set it. So, I'm fairly certain that I'm aligned correctly on my True South Satellite, and that the Declination Angle is set correctly. I'm also fairly certain that the F/D and the Skew is set correctly. However, I'm still getting a very weak signals. Here at home on my Winegard 10' I get 74 channels on a Blind Scan for 91W. Over on the 7.5 Top 10, I only get 1 channel. That's how bad the signal strength is. The next time I go over, since I have a Dual Output LNBF, I'm going to take the receiver and a monitor out to the dish, hook up to the second output with a short piece of RG6, then do a blind scan to see what I get. I'll get back to you with my results.

 

[arlo]

You haven't mentioned if you've tried moving the lnb in and out to get better focus. And be sure it's aimed at the dead center of the dish before peaking initial signal.