True South vs True South *satellite*

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flyguyj

SatelliteGuys Family
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Dec 2, 2007
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There are a lot of conflicting statements around the web when it comes to setting up a motorized dish. Should you aim it to -no kidding- true south, or aim it to the closest satellite to true south for your location?

For us here, it's the difference between 167 degrees for true south, vs 169 for Satmex 6.
 
Turn on USALS and select and activate the satellite that most closely matches your longitude.

The motor will calculate the number of degrees of rotation and turn to the correct position. Now aim the dish.

The motor and dish when in the zero position will be aimed at magnetically corrected south.
 
I was thinking about that after I started to do something else.... I can almost always find 97W in less than 10 minutes. If I set this motor I was given at peak elevation then move the motor by USALS to 97W, I should be able to set the system on the ARC even though I am then over 20 degrees east of south. Correct?
 
Right, when it comes to Ku and a USALS motor, the designation of due or true south is almost irrelevant. Using that kind of setup, once you set it for your latitude and longitude, and you move the dish to the satellite you want, the motor has already accounted for the fact that your southernmost satellite is two degrees off your longitude.

If you have a big dish, though, nothing is automatic about that adjustment. You have to get zenith and then throw a few counts in the direction of the satellite in order to start off close to the right configuration.
 
Not to get off topic, but a basic compass reading is necessary before planting any dish. If a magnetic compass is reading 180 degrees south, isn't a true south heading entirely dependent on the location due to magnetic declination? I know in my location it is +5. I never see anything on this forum addressing this issue. Another thing that has always been puzzling to me, folks located in the southern hemisphere, do their dishes point north? Assuming all satellites are in stationary orbit above the equator.
 
Another thing that has always been puzzling to me, folks located in the southern hemisphere, do their dishes point north? Assuming all satellites are in stationary orbit above the equator.

Puzzle no more! Mostly, their dishes point almost straight UP (and north), because they are much closer to the equator, and nobody lives in Antarctica.
 
There are a lot of conflicting statements around the web when it comes to setting up a motorized dish. Should you aim it to -no kidding- true south, or aim it to the closest satellite to true south for your location?

For us here, it's the difference between 167 degrees for true south, vs 169 for Satmex 6.

Flyguy,

That is quite close enough not to worry about the difference. If you are using USALS, most of your job is accomplished automatically for you by the mathematical computations that the USALS feature offers.
As Brian (SatelliteAV) stated, you just desire to be somewhat close to true south or the truest southern satellite. If you have your H-H motor latitude adjustment and your dish elevation set properly (according to the installation guidelines and instructions for your specific site location and specific motor/dish assembly) then all you need to do is select a satellite and swing the dish east to west until you HIT the signal. The rest of the arc should fall right in place for you without much additional work or effort on your part.

I may be taking a bit of liberty in my statement above to make it sound so simple, but it really isn't too far from the truth. There are a few other considerations that you must realize. First of all, what if your nearest true southern sat is blocked by trees or buildings? Maybe the only sat you can possibly obtain a good LOS signal from is actually 26° to the west of your true south? Never fear, USALS is here!

LOL! Sincerely, you might be presented with a little additional labor in such a case, but it still works the same (just maybe not quite as convenient). The most convenient scenario would be that your dish install site was precisely at 97.0°W longitude thus making Galaxy 19 @ the 97.0°W orbital your TRUE southern satellite (this is just an example). I think that you foresee that this scenario is a no-brainer for the ease of alignment.

That sat is the highest in the sky for you and dead south of you. Your motor will be at its zero degree or home position and if you set up all the angles per the book, all you have to do is pick out a HOT transponder, set that sat and TP up to monitor on your receiver and then swing the motor mount on the vertical mast back and forth until you detect a BLIP of a signal and then fine tune it in. Pretty easy and straight forward, yes?

The other scenario.... The only sat you can get a clear LOS from is 26° off from your true south position. So what! Set up everything in the same manner first. Then command USALS to drive your H-H motor to that satellite's orbital position and select a HOT TP on that sat to monitor the signal from. The USALS program will automatically drive the motor to the proper position for that specific satellite. The angle of the dish will automatically be set to follow the arc to that satellite and all you have to do is swing the motor on vertical mast back and forth from east to weat until you detect the signal from that specific TP on that sat, fine tune it and lock'er down.

NOTE: Always verify that you have hit the right TP and SAT before you lock everything down. Scan the TP to gather channels and then compare the scanned channels to the channels which are supposed to be on that TP and SAT to ensure that they match.

So, now a quiz for you...

Q: If your actual site longitude were 113°W, can you set up your H-H motor using satellite Galaxy 19 @ 97.0°W instead of SatMex 6 @ 113.0°W?
A: You bet you can, and just as easily, provided you use USALS motor positioning.

Q: Does it matter if you aim for real true south, the true south satellite or any other satellite when using USALS?
A: I will let you answer that for yourself in your next post / reply here.

RADAR
 
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the answer to the question is....the motor itself must be aimed at true south,

however, to aim you can use any satellite that is relatively close to south, as long as you drive the motor to the satellites location FIRST (before aiming) using USALS,

then when aiming you swing the entire motor/dish assembly on the pole to adjust azimuth, for elevation adjustments, you move the dish only, not the motor,

the motors latitude scale should always be set to your latitude

i have aimed motors using satellites that have been +/- 10 degrees of "true south"
 
Awesome replies. This is the stuff that doesn't seem to make it into these cheesy generic manuals that I have been reading and re-reading! RADAR - I coincidentally did the same process you posted yesterday evening. My line of thought was, "if I can at least get it on the arc, then it shouldn't matter, and it should stay on the arc if everything is set up properly." Fortunately everything was set up properly, and I get signal on everything that isn't blocked by the mountains to the east! Fun stuff! Now I just need to learn more about the receiver to take advantage of all this! Thanks again!
 
radar is back!!! a wealth of information back on line... glad to see you are back radar. the other day i though you were back because you were in a post and i can't count how many folks said 'look at the date on radar's post'. ooopppsss i said... now i know you are alive and well.... charlie
 
Mikey11 said:
the motors latitude scale should always be set to your latitude

The problem is that some scales are just wrong, as is the case with my Powermax SG9120B. Also, the mounting bracket should not be trusted to maintain the plumb relationship from pole to tube (i.e. mounting mast and motor tube being parallel when set at 0 degrees).

You should always check and adjust the motor tube so it is plumb at 0 degrees.
 
The problem is that some scales are just wrong, as is the case with my Powermax SG9120B. Also, the mounting bracket should not be trusted to maintain the plumb relationship from pole to tube (i.e. mounting mast and motor tube being parallel when set at 0 degrees).

You should always check and adjust the motor tube so it is plumb at 0 degrees.

My sg9120b latitude scale is off by at least 2 degrees. I finally had to set it using an inclinometer
 
My sg9120b latitude scale is off by at least 2 degrees. I finally had to set it using an inclinometer

My lat scale was off 5 degrees or more. The motor mount was off more than a degree in the east-west plane too.

The Powermax SG9120B, "The Puppy Mill H-H Motor!"
 
My sg9120b latitude scale is off by at least 2 degrees. I finally had to set it using an inclinometer

i dont really believe your scale was inaccurate, i think your motor bracket was probably not level,

most people assume that their motor is level just because their mounting pole is level, this is incorrect and should never be assumed,

after you have aimed the motor and tightened all the bolts up you should use a level to make sure the motor itself is level, just because the mounting pole is level that does not mean the motor will be,

if the motor is not 100% level, the mounting pole should then be re-adjusted to compensate, to make sure the motor itself is level, this may mean the pole is not level, but that doesnt matter, its the motor itself that needs to be level, not the pole
 
Mikey11 said:
i dont really believe your scale was inaccurate, i think your motor bracket was probably not level,

most people assume that their motor is level just because their mounting pole is level, this is incorrect and should never be assumed,

after you have aimed the motor and tightened all the bolts up you should use a level to make sure the motor itself is level, just because the mounting pole is level that does not mean the motor will be,

if the motor is not 100% level, the mounting pole should then be re-adjusted to compensate, to make sure the motor itself is level, this may mean the pole is not level, but that doesnt matter, its the motor itself that needs to be level, not the pole

WOW... If this post doesn't totally confuse a newbie, not sure what will!!! :)
 
i dont really believe your scale was inaccurate, i think your motor bracket was probably not level,

most people assume that their motor is level just because their mounting pole is level, this is incorrect and should never be assumed,

after you have aimed the motor and tightened all the bolts up you should use a level to make sure the motor itself is level, just because the mounting pole is level that does not mean the motor will be,

if the motor is not 100% level, the mounting pole should then be re-adjusted to compensate, to make sure the motor itself is level, this may mean the pole is not level, but that doesnt matter, its the motor itself that needs to be level, not the pole


You can believe what you want, it's a free country. You are 100% wrong. The scale on the side of this Powermax motor is absolutely printed off several degrees. I can assure you everything is leveled, including the bracket and the pole, thank you. Do a search around here, and you will find others reporting the same thing about the scales being printed off.

I used a digital inclinometer, and verified it with a standard level.

By the way, I've been using and installing dishes for 30 years, and installed my first c-band dish with polar mount back in the early 1980's. So I'm well aware of the need for having everything set level from the start.
 
By the way, I've been using and installing dishes for 30 years, and installed my first c-band dish with polar mount back in the early 1980's.

Sweet so please tell me you have boxes of VHS tapes of old c-band shows you can donate to the archive? :)
 
Sweet so please tell me you have boxes of VHS tapes of old c-band shows you can donate to the archive? :)

No, but I got ripped off personally by Shaun Kenny, who stole an original 010 Videocipher from me. Over $1,000, back when that was a LOT of money! Not just a module, he stole and never paid me for the entire decoder after he sold it on Greensheets. Then they declared bankruptcy, and I couldn't do anything to get any money back.
 
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