Thread: DG-380 Motor Scale Setting

I'm finally setting up the DG-380 Motor on a 1.2M GeosatPro Dish after a loooooong delay. My question(s). Do you set the Latitude scale on the motor using the scale's leading edge or do you use the raised pointer on the scale? Just to confirm........during setup you can adjust dish elevation/Azimuth on the true south satellite and only adjust Azimuth East and West of the true south satellites?

Originally Posted by Babadem

I'm finally setting up the DG-380 Motor on a 1.2M GeosatPro Dish after a loooooong delay. My question(s). Do you set the Latitude scale on the motor using the scale's leading edge or do you use the raised pointer on the scale? Just to confirm........during setup you can adjust dish elevation/Azimuth on the true south satellite and only adjust Azimuth East and West of the true south satellites?

Babadem,

There is a small, raised arrow on the lower half of the motor housing (shell) near the bolt in the scale slot on each side of the motor. This is what is supposed to be used as the marker.

RADAR

Originally Posted by AcWxRadar

Babadem,

There is a small, raised arrow on the lower half of the motor housing (shell) near the bolt in the scale slot on each side of the motor. This is what is supposed to be used as the marker.

RADAR

Thanks, RADAR........What is your take on my second question above?

Babadem,
I make the initial adjustments at the true south bird.
Then I move out west and make sure that 123W decent. Might even push and pull on the dish to see if an elevation adjustment would make sense.
IF the west bird is satisfactory, then I'm done.
IF the west bird is not satisfactory, I've got to find out what went wrong and correct it.
IF the pole is plumb and your motor latitude setting is correct, then dialing in your true south bird is all you will need to do.


[edit] Note my Fortec 1.2M dish in the pic. Turns out that I had to put a support cable on the support arm and draw the lnbf into the optimum position. The side arms simply didn't position it very well. Hopefully , your results will be better.

Originally Posted by Babadem

Just to confirm........during setup you can adjust dish elevation/Azimuth on the true south satellite and only adjust Azimuth East and West of the true south satellites?

Babadem,

You could follow my thread here http://www.satelliteguys.us/free-air...m-antenna.html (Installation of the GeoSatPro 1.2 M antenna) to compare some notes and get some ideas as you go along.

To answer your question, I need to explore some other items as references.

If you are fortunate enough to get the motor latitude angle and the dish elevation angle set perfectly spot on right off the bat, you shouldn't have to make any further adjustments other than the azimuth at the true south satellite.

That is in a perfect and ideal world, of course.

In my world, I find that things don't fall into place so conveniently. So I take extra steps to ensure that the angles are set precisely. I always use an inclinometer on the bottom of the motor (without the dish attached to the motor tube) and set the reading on the inclinometer to 90 - latitude. I get a much more precise setting this way and I don't have to worry about what to use as the pointer on the motor's latitude scale or if I have the pointer dialed in to the precise angle marking on the scale. A good inclinometer placed fully flush on the flat bottom of the motor housing will provide a more accurate reading for this setting. Then you can set it here and forget it.

On page 2 of the DG-280 or DG-380 manual - ALIGNMENT OF THE MOUNT, it tells you how to set the dish elevation. In your case and mine, we cannot follow this instruction because we are both using the GeoSatPro 1.2 M dish. The mount for this dish must be inverted so that it will fit on the motor tube from the bottom, and therefore the dish elevation scale won't read properly. I need to mention here, that since I inverted the dish bracket as it installs on the motor tube, I also inverted the dish reflector on its mounting bracket so that the bolt holes for the LNBF support arm and side support struts are again at the bottom of the dish.

This makes the elevation scale incorrect (upside down) for my installation. The instructions which came with this dish explain how to correct for the variance in the angle if you have to install it in an inverted position.

Once these two angles (motor latitude and dish elevation) are set, then you can dial in the east - west azimuth to pick up the true south satellite signal. When you find this signal, fine adjust the dish elevation and east - west azimuth to peak the signal. You may also wish to adjust the focal position of the LNBF and ensure that it is set to zero degrees polarity to aid in peaking the signal.

So now, we are at your specific question... "during setup you can adjust dish elevation/Azimuth on the true south satellite and only adjust Azimuth East and West of the true south satellites?"

The procedure below is what I have been following in this regard and it does seem to work fairly well:

Drive the motor to the east most satellite that you can detect a signal from and adjust your dish elevation (and only the dish elevation) for the best possible signal. Then drive the motor to the west most satellite that you can detect a signal from and adjust your azimuth (and only the azimuth) for the best possible signal. Repeat this process until no improvements can be made in the signal QUALITY.

The procedure above was recommended by Tim Heinrichs in January of 2008.
Mr. Tim Heinrichs is the CEO of DMS International. DMS International is the manufacturer/importer of the SG-2100 motors.

You can try this if you wish. Otherwise, you can simply try to adjust the elevation at or near the true south satellite and adjust the azimuth at the extremes of the arc in order to peak and tweak the signal.

I should state that there is really no right or wrong way to accomplish this. Simply use and adopt whatever seems to be most convenient for you and that provides the best results with the least amount of labor. Once you have adopted a system, you can refine it later if you are going to set up many dishes down the road. If you are just going to set up one dish for your own use, you can play and experiment for the best possible signal from all your favorite satellites and you don't need to apply any specific set of rules.

For instance, I watch RTV most often, so I have tweaked and peaked my dish and motor and LNBF for the best possible signal from 83W and the RTV transponder. Since this is the most difficult (lowest quality) signal for me to acquire, I may sacrifice some of the signal quality on several other satellites to accomplish my personal goal. I can still watch the other satellites just fine, but their signal is not peaked to maximum.

RADAR

Babadem,

I would like to add some hints for you on the installation of the GeoSatPro 1.2 M dish.

First of all, for a larger offset dish, it is quite friendly to install. I found it a lot easier than my 1.0 M Winegard.

NOTE 1: This dish comes with two "U-bolts" to clamp the dish bracket to the motor tube, but there are three sets of holes in the dish clamp or bracket so it does allow for three "U-bolts". You will be more pleased if you head on down to the hardware store and pick up a third "U-bolt".

The fitting of the dish clamp on the motor tube of the DG-380 motor isn't very snug, so the third "U-bolt" will assist in improving this so that the dish cannot spin on the tube so easily. Some anti-skid or anti-slip tape (that sandpaper-like tape) around the motor tube will also prevent this slippage.

NOTE 2: Also, you want the vertical axis of the dish assembly to line up perfectly with the vertical axis of the motor tube. In the thread I linked to in the previous post, there is a picture of what I used to set this as best I possibly could.

NOTE 3: When you attach the two side supporting struts to the LNB support arm there is a little confusion here in my opinion. If you attach them as depicted in the instructions that come with the dish, it appears that you should attach the support struts to the very end of the LNBF support arm. However, there is another set of holes drilled in the LNBF support arm back a couple inches from the end.

If you use the holes at the very end of the LNBF support arm, then the mounting bracket for the LNBF will be very rigid and stable - like you think that it should be. This seems appropriate, but also makes it difficult to make any adjustments to the LNBF focal distance or polarization. However, if you try to attach a C-Band LNBF with a scalar ring, you will not have enough clearance for the scalar ring as the side support struts will restrict it.

If you use the holes set back from the end of the LNBF support arm, the standard LNBF support clamp will seem to be very loose and you can actually rotate it a few degrees CW/CCW which may affect the polarization of the LNBF. Since the end of the LNBF support arm is round and not square, the clamp doesn't seem to fit it properly or logically.

Neither method here seems totally right nor totally wrong, but there is a slight difference between the two as the dish elevation angle will need to be readjusted slightly to compensate between the two.

RADAR

Originally Posted by brentb636

Babadem,
I make the initial adjustments at the true south bird.
Then I move out west and make sure that 123W decent. Might even push and pull on the dish to see if an elevation adjustment would make sense.
IF the west bird is satisfactory, then I'm done.
IF the west bird is not satisfactory, I've got to find out what went wrong and correct it.
IF the pole is plumb and your motor latitude setting is correct, then dialing in your true south bird is all you will need to do.


[edit] Note my Fortec 1.2M dish in the pic. Turns out that I had to put a support cable on the support arm and draw the lnbf into the optimum position. The side arms simply didn't position it very well. Hopefully , your results will be better.

Thanks, brentb63 for the info.