Sat Location problem

[Long Hair]

Ok first off my true south sat. is 95west. So 91west to 137west I receive a signal, but when I go to 91west and further east I lose signal. Last time I started a thread my problem was on sat 89west I think, my signal came in better when I was in front of my dish. The signal would jump up about 10% quality. So my ? is, could I be one sat position off ether east or west and have this problem. I moved my true south 95 to the 93 spot, so 93 became 95,95 became 97 and so on and so forth. The reason I moved my dish in the first place is because my dish superdish was pointing at 97west. And my big dish was pointing at a different location for 97west. Before moving my true south my signal on 89west was at best 8or9 higher on the quality.

Some help please, thanks for your time.

 

[Lak7]

The reason I moved my dish in the first place is because my dish superdish was pointing at 97west. And my big dish was pointing at a different location for 97west.

What Dish / Motor setup are you having a problem?

 

[Long Hair]

What Dish / Motor setup are you having a problem?

My big dish is a 7.5 unimesh, this Is the one I'm having problems with. The superdish is just mounted on a tripod mount, just for testing with the fss lnbf. Like I said the unimesh signal for pbs on dvb and 4dtv come in with better quailty when my body is in front of the signal, on 89° W Galaxy 28 T4/L4/T8. I thought maybe some of the problem could be the fact that my big dish and pole are not grounded, letting it pick up to much noise and not enough signal? But it only kills the signals to the east of my true south sat. I found that my biggest problem setting my true south 95west, is my signal stays about the same for 95,between 93-97west.

 

[Lak7]

Your Feed must be centered and pointing the the center of the dish!!!!
I measured a million times, never got it "prefect". So I disconnected the Arm and carefully flopped the Dish over.Gave the Dish "the string test" on Front and Back, then from behind the Dish, I looked thru the the center plate hole and sighted the strings to the Feedhorn (cap removed, DMX741) and adjusted so the Probes were aligned to the strings.

Focus on the Trues South first.
Do you have Ku on the BUD?
Start with C Band
Drive the Dish to it's highest point, it's hard to be exact, but try
I looked up Joplin,Mo , your location - 37.1, -94.5
Check that the Mount is Plumb
Set your Main Axis angle - 37.75
Set your Declination - 5.56 (37.75 + 5.56 = 43.31) (46.69 on back of Dish) (43.31-90 = 46.69)
On my Unimesh, there is no good place to measure this, so I just winged it. I got close by using the back center of the Dish.
Set receiver / meter for Hot TP on 95 west
Loosen Mount Bolts and rotate the whole thing to find peak signal, make a reference mark on the Pole and Mount.
Repeat for 93 west, no need to adjust any angles, just rotate the whole mount to peak signal and mark just the Pole, aligning to the Reference Mark on the mount.
Your Marks should be about 1/16" apart, your goal is to get the Mark on the Mount 3/4 towards the Mark for 95, that should get you 94.5.
Now make sure the mount is Plumb
Recheck / Reset the Main Axis angle

If everything is set correctly, you should need to drive the Dish a few clicks to the West to peak signal.

Drive the Dish the the East, say 72 west, then to the lift & lower the Dish by the Rim, make note of what makes it Signal better - no adjustments yet

Then drive to a Sat to the West, say 125 west, lift & lower, make note of what makes the Signal better.

Your adjustments will be Azimuth and Declination. Don't adjust the Main Axis from your proper setting, just make sure your Mount is Plumb to the Pole.

Bottom of the page explains what to do using the notes you made.......
Footprints by Dish Size - Adjusting the Polar Mount for Prime Focus Antenna - C/Ku-Band Satellite Systems - Tuning, Tracking, Azimuth, Elevation, Declination Angles, F/D Ratio, Focal Distance, Inclinometer, LNB/Feedhorn Assembly, Actuator Assembly, C

Now, back to 95, switch to Ku, and repeat.

 

[Lone Cloud]

How did you get the zenith position on the big dish? The dish needs to be at zenith when it is pointing at your due south satellite. Is there a marker on the mount to indicate the zenith position? I'm unfamiliar with that dish.

Basically the dish has to be at zenith and when aiming at your due south satellite, you leave it at zenith and only adjust for up and down and rotating it on your mounting pole.

Do you have your declination offset at the right angle? That declination angle is based upon your latitude. there are graphs. around five degrees down tilt usually gets you close,

 

[crackt]

use a builders square on your dish mount. when the mount is square the dish is at zenith.

crackt out,.

 

[Long Hair]

How did you get the zenith position on the big dish? The dish needs to be at zenith when it is pointing at your due south satellite. Is there a marker on the mount to indicate the zenith position? I'm unfamiliar with that dish.

Basically the dish has to be at zenith and when aiming at your due south satellite, you leave it at zenith and only adjust for up and down and rotating it on your mounting pole.

Do you have your declination offset at the right angle? That declination angle is based upon your latitude. there are graphs. around five degrees down tilt usually gets you close,

I found my zenith with a compass. But I found out that a few degrees east or west of my true south reads about the same quality. The declination is set to the best of my knowledge. Lak helped with this a few months ago.

 

[Lone Cloud]

I found my zenith with a compass. But I found out that a few degrees east or west of my true south reads about the same quality. The declination is set to the best of my knowledge. Lak helped with this a few months ago.

Nosir. You apparently don't get what I'm driving at. You can't find your dish zenith with a compass.

The dish zenith is the absolute highest point it gets to. Your dish dips down to the East and then travels the other way and dips down to the West. The zenith is its highest point, independent of compass direction. It is dead center in between all the way East and all the way West. It is the point at which the very top of your dish is at its highest altitude point. You get the highest point first, before you aim at your due south satellite. Let's say you tied a really sensitive altimeter in the very top of your dish on its edge. The point of highest altitude is the zenith.

For example, on my Birdview dish, it has a flat plate on the back of it, and a boxed steel as part of the mount. Using a small carpenter's square, I put one edge on the flat plate and then click my mover until the other edge of the square lines up with the side of the box steel.

Different dishes will have different methods to discover zenith, which is why I asked if there were any markers on your mount. A picture of your mount might help.

A compass won't find your zenith

 

[phlatwound]

Long Hair, sounds like you may be confusing zenith with azimuth. You can find your azimuth with a compass, but not your zenith.

Your dish is at it's zenith when the dish is pointing at the highest elevation it will point at in the travel of the polar mount.

 

[Long Hair]

My Bad, I found my zenith with the polar mount itself. I just lined up the mount where it pevets east to west.

 

[Lak7]

I found that my compass got me close enough to start.
Marking the pole is what got me spot on.

 

[Long Hair]

I found that my compass got me close enough to start.
Marking the pole is what got me spot on.

Tomorrow I'll try to set my south again and mark the pole this time and see if I can get the east and west side of the arch.
FYI I have dmx741 lnb, the downside of my setup is for dvb-s, all I have is a pci card, no STB. Thanks for the info, hopefully I'll post something good in a day or two.

 

[Lone Cloud]

My Bad, I found my zenith with the polar mount itself. I just lined up the mount where it pevets east to west.

It's why I asked about zenith - because your aiming problem looked like it might have something to do with it.

Looks like you should be able to tweak it from there. I have personally had very good luck with a "beep on scan" receiver, with wireless headphones at the dish. I don't know if your receiver has that, but it's a pretty good way to get the best reception - easier than bringing a little tv a receiver and extension cords out to the dish.

 

[Lak7]

I have dmx741 lnb

Yep, me too.

the downside of my setup is for dvb-s, all I have is a pci card, no STB

That does make it a little harder.

 

[Long Hair]

Well after playing around with my dish, I'm now able to scan the sky from 72 west - 137 west. What I did was moved the dish mount about 1/4 inch to the east,and moved the elevation up a hair. It's not perfect,but it work's. So now I guess I need to focus on the declination angle, since I moved the elevation. Thanks again to everyone for your input. One ? what's the best way to check that the declination angle is right. I assume checking each end of the arch? FYI: Both my C and Ku signal are coming in better than before.

 

[Lone Cloud]

Well after playing around with my dish, I'm now able to scan the sky from 72 west - 137 west. What I did was moved the dish mount about 1/4 inch to the east,and moved the elevation up a hair. It's not perfect,but it work's. So now I guess I need to focus on the declination angle, since I moved the elevation. Thanks again to everyone for your input. One ? what's the best way to check that the declination angle is right. I assume checking each end of the arch? FYI: Both my C and Ku signal are coming in better than before.

That looks like a pretty good range, but if you are located around 95 west you are reaching another 42 degrees west to get 137. Going east you should be able to reach 55.5 west, assuming no line of sight problems.

Usually declination is done first - sort of a "set it and forget it" deal.
The best way to do declination is to first determine how it's done on your dish. Once you have that figured out you go to a declination chart, find your latitude and see what they have listed on the chart - usually around 5 degrees here in the lower 48.

An inclinometer is most often used. Fairly inexpensive Home Depot item. You get your dish to its zenith, due south position, then you look for a place to get a reading off your polar mount. Then you look for a place to get your reading off the dish directly. The process results in tipping the dish up or forward the amount of the dec angle.

I think you might be close now though. A nearly 70 degrees of usable travel along the arc indicates you might need fine adjustment only. Where did you get your dish from?

If if was local, the declination angle would be already set for your latitude.

I hope it helps. Good luck

 

[Long Hair]

Lone Cloud"you are located around 95 west you are reaching another 42 degrees west to get 137. Going east you should be able to reach 55.5 west, assuming no line of sight problems."
I think my dish goes east to about 62 degrees before I reach my lower limit of my actuator. On the west end my dish moves a little past 139 degrees, so when the snows off the ground I could move the actuator and see more of the west side.

Lone Cloud"Where did you get your dish from?" It was local, but I've fooled around with it a lot. I put the dish up back in July, so this is something I've needed to do for sometime. Thanks for the info.

 

[Lone Cloud]

Lone Cloud"you are located around 95 west you are reaching another 42 degrees west to get 137. Going east you should be able to reach 55.5 west, assuming no line of sight problems."
I think my dish goes east to about 62 degrees before I reach my lower limit of my actuator. On the west end my dish moves a little past 139 degrees, so when the snows off the ground I could move the actuator and see more of the west side.

Lone Cloud"Where did you get your dish from?" It was local, but I've fooled around with it a lot. I put the dish up back in July, so this is something I've needed to do for sometime. Thanks for the info.

Well, if you can go 45 degrees in one direction, but only 33 degrees in the other, maybe your actuator isn't in the middle of it's throw at zenith/due south. Basically if you unhook your actuator from your dish and measure from all the way out to all the way in, and then put a mark on it for half way between, you should be on that mark at due south.

But not knowing your setup, for declination, get it on due south, then find a place on the polar mount to get that angle, then if there isn't any place on the back of the dish itself to get that angle reliably get a straight 2x4 put it on the front of the dish top to bottom, take your inclinometer reading off of that.

My opinion is that you are close if you can get that much of the 'Clarke Arc'.

 

[Lak7]

Well, if you can go 45 degrees in one direction, but only 33 degrees in the other, maybe your actuator isn't in the middle of it's throw at zenith/due south.

That's just how Actuators work, not like H to H setups. With the arm retracted, you set the clamp to the Lowest Sat you wish to receive, then drive it out. It dependson the Arm length, and mount design, as to how much of the Arc you will get.

 

[Lone Cloud]

That's just how Actuators work, not like H to H setups. With the arm retracted, you set the clamp to the Lowest Sat you wish to receive, then drive it out. It dependson the Arm length, and mount design, as to how much of the Arc you will get.

I know what you mean. My first big dish was actuator type. Actually I modified that mount to take advantage of the 24 inch throw the actuator had, and used my centering method,

We are hampered by not seeing his dish and mount, Flying blind somewhat.