OTHER Help Peaking a 1.2m on HH-120

[Captain Midnight]

I am needing some advice on how to peak my ku dish to hit all of the arc on target. Currently, I have not had any issues with 87w-125w, but I went out to see if I could squeeze more signal from the 129w Reuters News feed...

Well, I go out there with my Sathero meter and have around 9db C/N. Not bad. Solid lock. But I go nudging and pushing on the dish. I raise the dish using the bolts on the back of the dish and get the signal peaked around 12.8db, reaching 13db at times. I double check my dish is on point by moving east/west.

Then I go back to 91w. It is my south satellite. I live at 92.2w. My signals there are now either weak or completely out, so I lower my motor elevation angle to peak the signals on 91w.

Back to 129w, and the signal is back down to around 9.5db and actually come up a half dB when I move the dish east just a bit. I have to raise the dish back to get the 13db back.

Then I realize I am in a loop of going back and forth.

How should I properly set up this dish to hit everything including 129w? Is that even possible? This fiberglass 1.2m is heavy and I have to drive it back east quite a bit on the western end of the arc when the weight really pulls on the motor.

Any advice is welcome and pardon my MacGyver'd dish mount. I made an adapter plate to put my 1.2m on a mount for a 75e dish...

 

[a33]

First questions:
1. Is the pole exactly plumb, east/west-wise?
2. Are motor and dish exactly in line, while at zero-position?
That is absolutely needed.

3. Are you using USALS (GotoX) or diseqc 1.2 (GotoNn)?

4.
Then you can check part 7.1 till 7.5 of the STAB manual: https://www.dmtrade.pl/download/instrhh120.pdf
However, for 7.2 and 7.3: rotate in the other direction than they say!
At 7.4 and 7.5, changing the axis elevation usually also calls for changing the declination setting, in the opposite direction.

BTW If this step calls for many adjustments, you could also go back to setting the axis elevation angle and dish declination offset angle from scratch, again. In that case, use the so-called "modified motor angles"!
The chart here is gone, alas: Elevation / declination chart
But there is always the one at the bottom, here: Footprints by Dish Size - Latitude Declination Chart - C/Ku-Band Satellite Listing
That could give a fresh start to the steps 7.1 - 7.5.

Does this help?

Greetz,
A33

BTW Does your motor have only one clamp on the mast? Ouch! That could cause instability, as well!

 

[cyberham]

Assuming you've followed A33's suggestions, and assuming declination is correct, I was taught to only adjust elevation at your highest point in the arc and then only adjust azimuth at the extreme ends. By going back and forth doing this, you should eventually end up exactly on the arc.

 

[Captain Midnight]

First questions:
1. Is the pole exactly plumb, east/west-wise?
2. Are motor and dish exactly in line, while at zero-position?
That is absolutely needed.

3. Are you using USALS (GotoX) or diseqc 1.2 (GotoNn)?

4.
Then you can check part 7.1 till 7.5 of the STAB manual: https://www.dmtrade.pl/download/instrhh120.pdf
However, for 7.2 and 7.3: rotate in the other direction than they say!
At 7.4 and 7.5, changing the axis elevation usually also calls for changing the declination setting, in the opposite direction.

BTW If this step calls for many adjustments, you could also go back to setting the axis elevation angle and dish declination offset angle from scratch, again. In that case, use the so-called "modified motor angles"!
The chart here is gone, alas: Elevation / declination chart
But there is always the one at the bottom, here: Footprints by Dish Size - Latitude Declination Chart - C/Ku-Band Satellite Listing
That could give a fresh start to the steps 7.1 - 7.5.

Does this help?

Greetz,
A33

BTW Does your motor have only one clamp on the mast? Ouch! That could cause instability, as well!

Yes, only one clamp for now. I had a nut seize up on the other during a prior installation. I had to take the grinder to it...

 

[Captain Midnight]

Assuming you've followed A33's suggestions, and assuming declination is correct, I was taught to only adjust elevation at your highest point in the arc and then only adjust azimuth at the extreme ends. By going back and forth doing this, you should eventually end up exactly on the arc.

Yes, but I was concerned because I kept adjusting and eventually my 'Latitude' setting on the motor was at 38. And my location is 35.5 N. I rounded up to 36 because I have my C band polar mount elevation on 36.1°, per the modified elevation chart.

 

[Captain Midnight]

I forgot to mention I am using USALS on everything from 87-95. West of that I have to use Diseqc 1.2 positions because of the play in my motor pin that only developed while trying to hammer down the dish mount bracket. The dish is still centered on the pin. I try to keep it plumb to a 0.1° room of error. Here are some reception numbers I have on Montana PBS @13.8dB and HD01 15.4dB (125w)
I don't know why 129w seems to have such a drop off.

First questions:
1. Is the pole exactly plumb, east/west-wise?
2. Are motor and dish exactly in line, while at zero-position?
That is absolutely needed.

3. Are you using USALS (GotoX) or diseqc 1.2 (GotoNn)?

4.
Then you can check part 7.1 till 7.5 of the STAB manual: https://www.dmtrade.pl/download/instrhh120.pdf
However, for 7.2 and 7.3: rotate in the other direction than they say!
At 7.4 and 7.5, changing the axis elevation usually also calls for changing the declination setting, in the opposite direction.

BTW If this step calls for many adjustments, you could also go back to setting the axis elevation angle and dish declination offset angle from scratch, again. In that case, use the so-called "modified motor angles"!
The chart here is gone, alas: Elevation / declination chart
But there is always the one at the bottom, here: Footprints by Dish Size - Latitude Declination Chart - C/Ku-Band Satellite Listing
That could give a fresh start to the steps 7.1 - 7.5.

Does this help?

Greetz,
A33

BTW Does your motor have only one clamp on the mast? Ouch! That could cause instability, as well!

 

[a33]

I forgot to mention I am using USALS on everything from 87-95. West of that I have to use Diseqc 1.2 positions because of the play in my motor pin ...

In the case of using USALS (not sure what the influence might be of your 'play', I don't take that into account here),
steps 7.2 and 7.3 can be somewhat different.

Outlining of some center sat position is done with USALS: move to that sat position with your receiver, and then rotate the motor+dish combination till you have best reception on that satellite.

After that, when checking the steps 7.2 and 7.3, there should normally only be differences as described in 7.4 and 7.5.
When you need to bend up at the one side, and down at the other side of the arc (so when it is asymmetrical, east and west), that is an indication of dish and motor not being in line properly (my question 2, in the previous post).
[Or, I once had that, the LNB arm not centered properly to the dish.]

In that case, the motor should be rotated as I indicated above for steps 7.2 and 7.3, but the dish on the axis should be rotated the opposite direction, so that motor and dish end up again in the earlier (succesful) USALS-position, if you can follow what I mean.

Greetz,
A33

 

[Captain Midnight]

In the case of using USALS (not sure what the influence might be of your 'play', I don't take that into account here),
steps 7.2 and 7.3 can be somewhat different.

Outlining of some center sat position is done with USALS: move to that sat position with your receiver, and then rotate the motor+dish combination till you have best reception on that satellite.

After that, when checking the steps 7.2 and 7.3, there should normally only be differences as described in 7.4 and 7.5.
When you need to bend up at the one side, and down at the other side of the arc (so when it is asymmetrical, east and west), that is an indication of dish and motor not being in line properly (my question 2, in the previous post).
[Or, I once had that, the LNB arm not centered properly to the dish.]

In that case, the motor should be rotated as I indicated above for steps 7.2 and 7.3, but the dish on the axis should be rotated the opposite direction, so that motor and dish end up again in the earlier (succesful) USALS-position, if you can follow what I mean.

Greetz,
A33

Thank you for the information. I will try to make time to really work on it soon. For now, all is well, but I may miss a feed on 127 or 129w with the current installation

 

[Captain Midnight]

Forgive the crude drawing but this is what I am experiencing. Basically my dish is tracking above 91w just enough to notice signal loss. 103w is peaked well and 129w is just being tracked a little under. So should I reduce declination with the dish bracket?

 

[a33]

Forgive the crude drawing but this is what I am experiencing. Basically my dish is tracking above 91w just enough to notice signal loss. 103w is peaked well and 129w is just being tracked a little under. So should I reduce declination with the dish bracket?

Does this mean you're getting (more or less) symmetrical results east and west, at step 7.2 and 7.3 of STAB-manual, now?
That is definitely the first step , I guess.

If yes, then indeed reduce declination of the dish in your case;
and as a result of the dish then looking higher, set the axis elevation lower again (as in 7.4).

Greetz,
A33

 

[Captain Midnight]

Does this mean you're getting (more or less) symmetrical results east and west, at step 7.2 and 7.3 of STAB-manual, now?
That is definitely the first step , I guess.

If yes, then indeed reduce declination of the dish in your case;
and as a result of the dish then looking higher, set the axis elevation lower again (as in 7.4).

Greetz,
A33

I would need to check further east. I can get signals on 67w and 58w, and I know there is a radio mux on 53w I can check. I really don't think I should send this fiberglass all the way to 30w due to the weight.

 

[Captain Midnight]

I tweaked things this weekend and was able to get the dish tracking well from 81w to 129w. I was able to lock a circular Dish TP on 61.5w but I couldn't find anything else down east. Last winter I had locked the 53w music mux and I used to find Sky Mexico TPs on 58w to help me align my dish on the eastern side of the arc, but I was unable to lock both. Some really weak data TPs tried to scan in. Signals are to intermittent to use for alignment.

 

[Captain Midnight]

Anyone have a few good TPs to use down around the 45-67w area? I used to lock Chinese Radio on 45w too. No luck lately.

 

[cyberham]

Data tps are on:

63W Telstar 14R/19V:
11505 H 21000
11634 H 25000
11634 V 34284

40.5W SES6:
10994 H 32729
11048 H 14000
11078 H 8571
11173 H 16382

I'm receiving all now.