Elevation and/or declination on a WS9036

[pjcl]

On the WS9036, there is a declination setting. There are scales on both sides of this setting. Should this be set to the declination number on the manual, or to the number resulting from the subtraction of that number on 40 degrees (motor bend)?

In summary, I'm in latitude 34.4, so I assume this is the number I set on the latitude scale closer to the motor (left side). Now, the booklet says that for my latitude, declination is 5.51. On that second scale, closer to the reflector, do I put 5.5, or 34.5 (40 minus 5.50)? I think this is confusing me because it happens to coincide with my latitude... also, I am skeptical because this second scale doesn't seem to allow much precision.

About the true south issue, is the solar noon a legitimate technique to use for this purpose? I found a website with the solar noon times for the entire year that correspond to my location.

As of right now, the system is up, and works fine motor wise. I haven't had much time to be on the roof, since I can only do it early mornings (it gets too hot up there after 11:00 am) which is impossible on weekdays. I haven't been able to pick up any signals yet, so I am trying to troubleshoot on the ground first...

Thanks guys!

 

[drboyddrboyd]

I've got the same dish, with the SG9100 motor; setting the elevation had me pulling my remaining hair out.

IMHO, the scales on the dish mount are of "cartoon" quality. What you want to do is to set your motor elevation very, very carefully, and then set your dish elevation relative to true horizontal using the number from dishpointer and a digital (or some other very accurate) angle setter.

This process got me close enough to get within bumping distance of a sat.

See my travails under the heading of "For the 9 millionth time - setting the elevation."

 

[pjcl]

I've got the same dish, with the SG9100 motor; setting the elevation had me pulling my remaining hair out.

IMHO, the scales on the dish mount are of "cartoon" quality. What you want to do is to set your motor elevation very, very carefully, and then set your dish elevation relative to true horizontal using the number from dishpointer and a digital (or some other very accurate) angle setter.

This process got me close enough to get within bumping distance of a sat.

See my travails under the heading of "For the 9 millionth time - setting the elevation."

That's another thing! There's two different slides on the latitude side, one starting on 35, and another that ending on 35, give or take. I assume we can use one or the other, depending on location, and to choose between one or the other, the motor is screwed on one or the other pair or orifices. Now, the problem is that at Lat 34.4, I'm borderline on both slides. One I can't use because when I put in the screw, it messes with the slide and forces a lower latitude. The other, since it does start at 35, doesn't have markings for lats below 35... I foresee a lot of trial and error...

 

[B.J.]

On the WS9036, there is a declination setting. There are scales on both sides of this setting. Should this be set to the declination number on the manual, or to the number resulting from the subtraction of that number on 40 degrees (motor bend)?

In summary, I'm in latitude 34.4, so I assume this is the number I set on the latitude scale closer to the motor (left side). Now, the booklet says that for my latitude, declination is 5.51. On that second scale, closer to the reflector, do I put 5.5, or 34.5 (40 minus 5.50)? I think this is confusing me because it happens to coincide with my latitude... also, I am skeptical because this second scale doesn't seem to allow much precision.

About the true south issue, is the solar noon a legitimate technique to use for this purpose? I found a website with the solar noon times for the entire year that correspond to my location.

As of right now, the system is up, and works fine motor wise. I haven't had much time to be on the roof, since I can only do it early mornings (it gets too hot up there after 11:00 am) which is impossible on weekdays. I haven't been able to pick up any signals yet, so I am trying to troubleshoot on the ground first...

Thanks guys!

The above is a bit confusing. The DISH shouldn't have a declination scale. Some BUDs do, when the dish mount is part of the polar mount, but the little offset Ku dishes don't have declination scales, so I'm confused. What the dish SHOULD have is an elevation setting, and you should set that to the motor bend minus your declination (use 4.9 instead of 5.5), and yes, subtract 4.9 from 40 (if that's the bend angle) to get 35.1 for the dish elevation.
Re precision, this dish elevation setting is just a starting point. You'll be adjusting this by peaking on your south sat.
Re true south, YES, solar noon is the best way to determine your true south, although this too is just a starting point, and will be tuned later using an extreme east or west sat. Just be careful, because this time of year some of the web pages that give these times don't correct for daylight time, so they may be off by an hour. Also remember, that it's your MOUNT, not your dish that you align to true south, although the dish can be used if you make sure it is centered properly on the bent tube, and the motor is at it's zero position. When you tune on your true south sat, however, you usually use the motor to turn to this sat using USALS before peaking, as it is typically not exactly at your longitude.

That's another thing! There's two different slides on the latitude side, one starting on 35, and another that ending on 35, give or take. I assume we can use one or the other, depending on location, and to choose between one or the other, the motor is screwed on one or the other pair or orifices. Now, the problem is that at Lat 34.4, I'm borderline on both slides. One I can't use because when I put in the screw, it messes with the slide and forces a lower latitude. The other, since it does start at 35, doesn't have markings for lats below 35... I foresee a lot of trial and error...

Use the one that starts at 35. You should be using a latitude of 35 anyway, not 34.4 .

 

[pjcl]

The above is a bit confusing. The DISH shouldn't have a declination scale. Some BUDs do, when the dish mount is part of the polar mount, but the little offset Ku dishes don't have declination scales, so I'm confused. What the dish SHOULD have is an elevation setting, and you should set that to the motor bend minus your declination (use 4.9 instead of 5.5), and yes, subtract 4.9 from 40 (if that's the bend angle) to get 35.1 for the dish elevation.
Re precision, this dish elevation setting is just a starting point. You'll be adjusting this by peaking on your south sat.
Re true south, YES, solar noon is the best way to determine your true south, although this too is just a starting point, and will be tuned later using an extreme east or west sat. Just be careful, because this time of year some of the web pages that give these times don't correct for daylight time, so they may be off by an hour. Also remember, that it's your MOUNT, not your dish that you align to true south, although the dish can be used if you make sure it is centered properly on the bent tube, and the motor is at it's zero position. When you tune on your true south sat, however, you usually use the motor to turn to this sat using USALS before peaking, as it is typically not exactly at your longitude.



Use the one that starts at 35. You should be using a latitude of 35 anyway, not 34.4 .

Thanks for your reply, B.J. So, if these scales are just for approximate reference, then it all makes more sense LOL. Here's what the User's Manual say, though. (see picture)

 

[B.J.]

Thanks for your reply, B.J. So, if these scales are just for approximate reference, then it all makes more sense LOL. Here's what the User's Manual say, though. (see picture)....

I assume that the manual picture is from the motor manual, not the dish manual?
Where that picture refers to setting the declination, that is correct in that that is the adjustment where you set your declination, however that is an elevation scale, not a declination, and the declination is really the difference between the 40 degree declination that you get from the bent shaft and the elevation you get from the dish elevation scale, ie the 40-5=35. Basically, there is no way that the dish mount can know what angle your motor's shaft is bent, so there is no way that that scale on the dish can be calibrated in declination. The dishes are generally calibrated assuming that they are Az/El mounts, ie fixed dishes on a pole. In that configuration, there is no declination. The declination is a negative tilt down towards the horizon, and the dish scale cannot give you a negative angle, only a positive angle, which is why you need the bent shaft.

Anyway, the dish elevation scale is where you set the declination, but it isn't a declination scale, it's an elevation scale. I think you understood that, but some people tend to say "I set my declination to 35" or something like that, thinking that the number on that scale is the declination, whereas the declination is actually 40-35=5. Sorry for being confusing, just the ex-teacher in me trying to keep things worded accurately when doing so only confuses people who already understood.

 

[pjcl]

B.J., I appreciate your explanation. I guess I never stopped to think about the fact that even though I receive both dish and motor from the same company and in the same package, they were not necessarily made for each other! LOL You hit the nail on the head when you say "there is no way that the dish mount can know what angle your motor's shaft is bent"! It is much more clear now. What still bothers me is that the mentioned declination scale does not allow for as much precision as the elevation scale. But then again, and according to what I have read before (scales being off), adjustments are always necessary anyway.

 

[Lak7]

Instructions give a Starting Point, it's results that count.
For me at least.

 

[pjcl]

Still nothing

OK, got on the roof after dinner tonight, and paid attention to the declination scale. I noticed that there is one on each side of the dish, but they do not correspond - they are inverted - goes up on one side (3, 4, 5) and down on the other (5, 4, 3 etc.)! So, setting at 35.1 on one side means almost no inclination, while setting 35.1 on the other, means what seems to be too much inclination towards the sky. While I was up there with all bolts loose, experimented alignment on elevation and azimuth, to no avail. It's hard without a reference point...

 

[drboyddrboyd]

At the risk of encouraging anyone to spend even more money on this hobby, I got one of these digital 1/10 degree (supposedly) angle gauges, and it's proven to be pretty darn handy....

Amazon.com: Wixey WR300 Digital Angle Gauge: Home Improvement@@AMEPARAM@@http://ecx.images-amazon.com/images/I/51ul2TNszfL.@@AMEPARAM@@51ul2TNszfL

 

[Lak7]

I noticed that there is one on each side of the dish, but they do not correspond - they are inverted - goes up on one side (3, 4, 5) and down on the other (5, 4, 3 etc.)

Is that on the Dish or the Motor?
If it's the Motor, one side should be marked "Latitude" and the other "Elevation"

Can you post a few Pics?

 

[B.J.]

Is that on the Dish or the Motor?
If it's the Motor, one side should be marked "Latitude" and the other "Elevation"

Can you post a few Pics?

Some motors have two ways to connect the motor to the mount, for different latitudes. I think his manual image shows this.

 

[Lak7]

Some motors have two ways to connect the motor to the mount, for different latitudes. I think his manual image shows this.

Then there is that too. The units I've seen just have 2 sets of holes for the bolts, but the Scales go in the same direction for each side of the Motor.

 

[Tron]

The SG-9120 has a choice of two slots to connect the motor to the mount, depending on your latitude.

The mention of the WS9036 in the subject of this thread was confusing me, as that is a dish and not the motor.

 

[pjcl]

Right, the scales on the motor make sense to me - latitude on the left, elevation on the right (from behind the dish), as the sum of these two is 90 degrees. What is puzzling me are the scales on the dish, the ones relating to the declination angle.

 

[Lak7]

Right, the scales on the motor make sense to me

Good. Set the Lat scale to you Lat, and forget it.
The Scales on the Dish are Elevation Scales that are normally used without a Motor.
However, when a Motor is used, you must compensate for the Motor Tube Bend, some are 30 degrees, others are 40. Using the Scale on the Dish, set to what the Motor's Manual suggests. Then try to lock a signal on your True South Sat.

Settings:
Motor Latitude Scale is set to Your Latitude
Dish Elevation is set to "Motor Tube Bend" minus "Declination Angle for Your Location"
Pole MUST be Plumb

 

[pjcl]

Thanks Lak7. Mine is 40 tube bend (it's one of the new SG9120's). I am also fortunate to have a satellite right on my true south (93W).

 

[drboyddrboyd]

So, you're getting there. Setting up a motor dish is not - trust me! - a simple matter. The first step is to make sure that your mounting pole is somewhere better than super-sturdy and exactly vertical.

The next step is to set the elevation of the rotational axis of your motor. Note that this is not your dish mounting shaft, it's the rotational axis of the motor. That axis should be exactly parallel to the earth's axis. (For some odd geometrical reason, it's higher by 0.6 of a degree - I cannot explain this)

The bottom line is that your motor rotational axis should point exactly 0.6 degrees directly above the north star. This is also your latitude plus 0.6 degrees above flat horizontal due north. This will mean that your motor body is pointed due south and the dish mounting shaft is "pointed" due south with the motor at the zero position.

Due south. Motor shaft pointed .6 above your latitude due north.

Now the easiest way to measure that is off the dish mounting shaft - just adjust by the 40 degree bend.

OK, now your motor is cool. Next step, set the dish elevation.

Look at dishpointer.com and find your required beam elevation above flat south horizontal for your true south dish. In your case, that's 50.0 degrees above true south flat horizontal. True south flat horizontal is the blue line on the picture.

In your case, the dish has an offset of 24.62 degrees. That means it's looking up at an angle of 24.62 degrees above where you'd think it would be looking.

So, you just 50-24.62 and your apparent dish angle has to be 25.38 degrees above true south flat horizontal. That's the red line in the picture - 25.38 degrees above true south flat horizontal.

How to measure that on a curved dish? Easy. Lay a very flat and straight board (I used a long level) across the face of the dish, resting on the lnb arm at the bottom and exactly centered at the top of the dish. It will just rest there by itself. This board will be exactly 90 degrees from your apparent dish angle. It's represented by the green line on the picture.

Do the arithmetic, set the angle on this board with something like the Wixey above, and voila! There you go!

These measurements, if done precisely, should get you well within "a bump or two" of your true south sat.

 

[pjcl]

OK, after reading something Iceberg posted about pushing the LNB towards the pan, I replaced the Spitfire (which didn't leave any room for adjusting the proximity towards the dish) with the one that came with the dish, the DMX521 0.2db LNB, pushing it all the way closer to the reflector. It may have been a coincidence, but I finally got signal. Also, on the dish declination scale, what should be around 35 for my latitude, is at 45! Again, when people say these scales are often off, they are right.

Anyway, I get the birds closer to the center, which are the ones I am most interested in. I foresee fine tuning to get to the extremes of the arc.

 

[LocutusOfBorg]

Good. Set the Lat scale to you Lat, and forget it.
The Scales on the Dish are Elevation Scales that are normally used without a Motor.
However, when a Motor is used, you must compensate for the Motor Tube Bend, some are 30 degrees, others are 40. Using the Scale on the Dish, set to what the Motor's Manual suggests. Then try to lock a signal on your True South Sat.

Settings:
Motor Latitude Scale is set to Your Latitude
Dish Elevation is set to "Motor Tube Bend" minus "Declination Angle for Your Location"
Pole MUST be Plumb

This still doesn't explain the meaning of the scales on each side of the DISH. Which one do you use? The numbers on each side of the dish don't end up being the same! Kinda hard to get the initial adjustment done with this dish. My motor latitude adjustment was easy to adjust compared to setting the dish elevation.