Sadoun 1.8M Polar Mount Assembly

[wrdavis]

My Sadoun 1.8M polar mount dish arrived around 4:30PM from UPS. There was no visible damage, but asked the driver to stay while I opened and checked the contents. The dish was well packaged with the 5 sided box inside another regular 4 sided box. A quick cutting the box open revealed no internal damage either. Would have been hard to imagine how any damage could occur with it double boxed, but maybe something could have been bent from the factory.

It arrived in 3 packages and I had assumed the big 5 sided one was the dish panels, a second would be the polar mount, and the third would be my GeoSat dual output C Band LNB. But I was wrong, the LNB was packed inside the biggest box with the dish panels. The other two were the polar ring mount and an unexpected 76mm diameter pedestal with three 21mm diameter fixed length braces and 6 anchor bolts.

I had already decided I would use one of my old Hughesnet J mounts for this dish and already had it mounted and plumbed. So the pedestal will be surplus. It is designed to mount on a concrete pad with the 6 anchor bolts. My J mount braces are adjustable in length, so plumbing it is a rather easy task even on my low slope garage roof. I would suggest the braces for the pedestal would be better if they also were adjustable. BTW there was one set of 6 anchor bolts with the pedestal and another set of 6 anchor bolts packed with the dish. None of these are listed on the parts diagram.

My first step was to modify a piece of PVC pipe I planned to use to help fill the gap between my 2 3/8” OD J mount and the 3” ID of the azimuth mount. Marked the bolt locations and length on the PVC. Then drilled oversized holes, so the azimuth mount bolts would not push against the PVC; but directly on the J mount steel. Finally cut the PVC to length. Inserted it into the azimuth mount and threaded the bolts through the holes which then would hold the PVC insert in place.

Second, sort out the hardware. This yielded a M6x50 mystery bolt not listed on the diagram. Also three other larger nuts & washers with no known function. They are the same size as the ones used to attach the ring mount to the polar mount.

Third, attach the polar mount to the azimuth mount. Note: to do this - first attach the elevation adjustment bolt to its bracket, before putting the hinge bolt in place.

Fourth, attach the angle iron to the ring mount. This was the worst part of the assembly. The factory welds the bolt in place on the angle iron bracket, but failed to mask the threads of the bolt. When the bracket is spray painted the bolt threads are filled with enough paint to make threading a nut on nearly impossible. Thought I’d just run a die over it and clean the threads, but my tap & die set isn’t metric. So had to take an Exacto knife and chip paint out until I could at least start the nut. Then used the nut to clean the excess paint from the threads.

Fifth, attach the triangular mount for the actuator arm onto the polar mount. Note the diagram shows this on the opposite side from what I determined would work best for me. But that varies with installation location across the country.

Sixth, attach the ring to the ring mount and angle iron bracket. Not sure which orientation is best for the bolts. I opted to have the bolt head towards the panels, but may discover later this isn’t the best direction. Note the dish support ring is different for the polar mount than for the fixed mount version that Sadoun sells. The fixed mount has three mounting brackets welded on. The polar version has no brackets, only six holes to allow attaching the ring mount and angle iron either left or right.

Seventh, by this time the 6Mx50 mystery bolt function became apparent. It holds the dish center cover in place. BTW, neither the center cover nor its bracket are listed on the parts diagram. Also not sure which side of the cover is front or back. Suspect it may become apparent with assembly of the dish.

Note the Sadoun 1.8M design differs from the Fortec design in how the declination adjustment is accomplished. This uses just one bolt, the other uses two. Looks like using only one would be easier to adjust. Also the ring mount bracket is long enough that a magnetic inclinometer can fit on the bracket to check the declination angle, without have to use a board or something to span the face of the dish. And the elevation can likewise be measured easily on the polar mount bracket.

The dish does not come with elevation and declination angle information. I took this data from Sadoun’s DG240 motor owner’s manual.

The cold front and its high winds are expected to blow out in a day or so. When it does, I’ll assemble the dish panels, attach the polar mount assembly and put it on my J mount.

Then install the actuator arm and find some satellites. I’ll have more pictures and text at that time.

 

[wrdavis]

Thought about the procedure I would use to get the assembled dish up on the garage roof. Decided to do it in two sections. First the polar assembly onto the mast and seond the dish assembly onto the polar. That would reduce the weight my wife and I would need to deal with.

That led me to think the ring assembly is best mounted to the dish first. Then in lifting the dish to the polar assembly only need to get one hole aligned for a bolt and the dish could be maneuvered to get the second and the rest. If I tried it with the ring already attached to the polar assembly, then all six brackets have to line up before it will nest together.

Did the dish assembly as Tron described, but on the living room floor. Marked the back of the Sadoun logo panel with an arrow. So I would be sure to have it right side up when done. After getting all six panels loosely screwed together, proceeded to go from opposite sides and snug the bolts slowly until all were finally torqued down.

Checked the measurements and did the focus and f/D calculations.
Diameter 72”, depth 11.5”, focus = 28.17”, f/D=.39

Carried the assembled dish outside and dropped the polar assembly onto the mast. Now plan to wait for the sun to warm up that side of the house before attempting to lift the dish onto the polar assembly.

So here’s some pictures so far.

 

[wrdavis]

Well once I had the mount up on the 2 3/8” J mast and I looked at it; I decided I just didn’t like that approach. It may have worked, if the dish didn’t come with a 3” pedestal mast. But the 3” pedestal mast was sitting in the box just talking to me to put it up instead. So looked it and its braces over, made some measurements, and came up with a plan to use it instead. I would reuse my existing adjustable braces for left-right support and one of the supplied fixed braces for fore & aft support.

I cut the triangular bolt mounting bracket off the bottom of the mast lowering the mast from 39” to 36”. I cut this off at the matching angle of the garage roof. To hold and allow the mast to be vertical instead of perpendicular to the roof; I needed some type of U channel. A trip over to the local steel supply shop and I looked at what they had. Nothing quite like what I had in mind. But they had 2x3x3/16 angle and I figured two 24” pieces of that, and I would make my own U channel to exactly fit the size of the 76mm mast diameter.

I made a second stop at the local hardware store for bigger lag screws, and other hardware including spray paint. Best color match for off the shelf paint was Rust-oleum “Pewter Gray”. A short piece of ½” pipe would reinforce the area where the ½” cross bolt would tend to squeeze the mast in the U channel.

A few hours measuring, checking, & drilling and I had parts ready to paint and let dry overnight. One of the things I changed while doing the drilling of the pedestal and base, was to make an angle iron extension for the actuator arm. It’s about 22” or about twice what the supplied bracket was. I drilled ½” holes spaced 2” apart to allow a selection for the arm. Figure with a 24” actuator, I ought to use more than just 6” travel or so for the satellites visible from my location (89 to 135).

This morning started assembling the brackets and parts onto the cut down mast. Drilled new holes through the roof directly into the rafter beneath, a bit of adjustment for plumb, torque down the bolts, some silicon caulk and I was ready to put the dish up. I wanted the dish up off the porch before trick or treaters tripped over it Halloween night.

A quick lift with a rope and the dish was on the edge of the roof. Now all that was required was jockeying the dish, aligning the holes in the ring support with the holes in the mount; so my wife could shove a bolt in place. This had to be done with the dish looking north in order to have a spot to stand. With the 3” cut off the mast height and the mount looking straight out horizontally, the dish hung just below the roof line. My wife worried I wouldn’t be able to rotate it south. I showed her that once the dish is elevated to 45 degrees, there’s no problem clearing the roof.

One of my concerns was would the LNB arms clear the service wires (phone & cable TV). Put the arms on and swiveled the dish, confirming lots of room between the arms and wires. I had lots of the 6mm bolts leftover, so used 2 per arm at the LNB. The parts diagram seems to only suggest 1 per arm at the LNB.

With the dish up and pointed south, finally installed the dish center cover with the mystery screw. But now have a mystery bracket that I think was the old way of attaching the center plate. The new way uses the ring connector bracket.

And with that, tightened down enough bolts to keep it from moving in the wind and figure, I’ll go about adjusting and aiming it tomorrow when fresh. Sure glad I don’t do this for a living, would be wore out all the time. And I had it easy on a nearly flat roof. How does an installer work on one of these antennas at the top of a ladder. Still baffles me.

So here’s some pictures so far.

 

[Tron]

Wow! Great work, Wrdavis! I think the 3" pole will work much better for you. I wouldn't have wanted to put such a large, heavy, and wind-loaded dish onto a J-pole. It looks like it will be far more secure on the included mounting pole.

The long-awaited cold front is coming through Southeastern Louisiana with a vengeance this morning, and once the frontal line clears out, conditions should be perfect (except for the wind, but I'll live with that since the dish is already mounted) to complete my install and start testing. My 500' roll of Perfect Vision PVCX3B finally arrived Friday, so once things dry out, it will be time to resume working ...

 

[wrdavis]

Just finished going through my channel list on the Pansat 9200HD. Checked against "the List" here and added some satellites and some more transponders for the C band I should be able to see.

Any advice for setting up an actuator and aiming at the due south bird?

Seems like the linear motion of the actuator is probably a SINE function when converted to angular. Maybe Cosine for all I know. So I was thinking taking the range of satellites and where on that range the due south one is. I might go as low as 87 up to 139, or a range of 52 degrees. My due south is 119 or 20/52 of the range. That's about .385 times 90 degrees for the first quadrant of the sine function, equals 34.6 degrees as the spot of the actuator that I'd think my due south bird should be on a sine function from 0 to 90 degrees. So the sine of 34.6 degrees is .568 times the max count of the Gbox 3000 gives 1136 as the actuator position I think I should extend the arm to before rotating the mount manually for the due south satellite. Also I'm thinking maybe this count needs to be scaled down to prevent going into the negative slope of the sine at 90 degrees. Perhaps .8 scaling factor would drop the count from 1136 to 909.

I've done the small Ku antenna motors, and they are set at zero for their due sourth and count up or down from there. But these linear actuators are are new to me.

 

[TRG]

Any advice for setting up an actuator and aiming at the due south bird?

.

C-band Satellite Installation

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

 

[wrdavis]

Thanks TRG, but neither site really answered my question and the first site adds to my confusion as to mounting the arm left or right side.


Clarifying my question. To manually adjust the azimuth of the mount on the pole for the due south satellite, the actuator arm will need to be at a setting somewhere between fully retracted and fully extended. What is a good way of knowing how many counts to run the arm out? The number of counts will need to be a fraction of the total depending where on the visible arc the due south satellite is located. I'm thinking this fraction isn't a linear relation but either a sine or cosine function.



Now for the first site's confusion factor to me. I don't see the advantage of having the arm on the west side over the east side or the other way round. In my case my due south is 119 in a range from 87 to 139 or 20/52 of the way from the western limit. So the arm will have to push the dish up the arc from 139 to 119 and the dish will help fall down the arc from 119 to 87. But in moving in the opposite direction the arm will have to push the dish up the arc from 87 to 119 and it will help fall down the arc from 119 to 139. Half the time it will be going one way or the other. So seems 50/50 to me. Why say one side is better than the other depending east or west of the Mississippi?



A common error made by both new installers and old-timers alike is in attaching the linear actuator arm. East of the Mississippi a Linear West setting is used. This seems counter-intuitive at first but closer examination will reveal the sense of this set-up. We want the actuator arm to push the dish into position and let gravity help to return it. From the eastern part of the country the lowest satellites will be on the western side of the arc. Therefore position the actuator arm on the west side of the dish (on the right when looking at the dish from behind). From the western part of the country the situation is reversed and the lowest satellites will be the eastern birds. West of the Mississippi, the actuator arm is attached to the left of the dish and called a Linear East Mount.

 

[woodheat/nooil]

Is your top sat is f3 at 119? I'm on the east coast and I have my motor pulling the dish to the west and pushing east. I tried it on both sides. I left it pulling back on the west to flatten out the dish for when it snows. One installer told me if i did not the snow load would bend the motor like a pretzel.

 

[wrdavis]

Woodheat,

Are you saying the side the motor is on changes the shape of the dish? Or are you saying that leaving the dish pointed where the snow can slide off easier.

Or is the idea to have the arm on the side where snow doesn't pile up and weigh down directly on the arm in conjunction with pointing at the lowest satellite.

That makes some sense. In my case in expected heavy snow, point it at 87 (the lowest in my arc so the face of the dish is more vertical) and have the arm on the high side of the dish in that orientation.

Yes when I said 119, I was referring the Anik F3 @ 118.7 on the list. Are the channels listed there still active? The call letters look a lot like the ones dropped in Ku from Galaxy 18 123W.

 

[woodheat/nooil]

"pointing at the lowest satellite" Yes, the dish then lets the snow slide off and not build up that much. As for F3 http://www.lyngsat.com/anikf3.html yes I found Cband stuff there.

 

[wrdavis]

I thought about my response, and the part where I say the arm is on the high seems wrong. The arm on the high side would be fully extended. I would think a fully retracted arm would withstand snow loads better than fully extended.

So I plan to switch the arm to the other side this morning, before doing the due south alignment. Does mean I'll need to drill another set of holes for my arm extender.

Also when I snowbird, think I'll leave my 1M dishes pointed at 87W for the same reason, let snow slide off easier. Never considered snow on them before while enjoying the sun in the desert.

 

[woodheat/nooil]

On my dish i just put the clamp that slides on the mover pipe close to the dish. no drilling needed. There is very little snow build up when my dish is set that low.

 

[Sadoun]

BTW, the model number for this dish that wrdavis is reviewing is SD180PM: Polar Mount Style.

 

[wrdavis]

Thanks Iceberg.



Well today was the day to get the dish aimed and aligned.

First I had to swap the angle iron bracket to the east side, and drill the additional holes in my extender arm bracket I made. So a good amount of time was waiting for the paint to dry on my bracket. So while that was drying, I tightened up some of the bolts a bit more on the mount. I had noticed some play on the polar axis and elevation axis. But tightening cured the play and still allowed movement.

Adjusted the GeoSat dual output C Band LNB so the 0 is at 9 o’clock position. Set the f/D at .39 and finished by marking the locations for future reference.
Finally the paint dried and I bolted the angle iron bracket with my extender onto the ring & mount. Marked the angles of my most eastern & western satellites on the top of the mount, so I could make certain the actuator arm would do its job without binding or hitting something. The concept I had of the extender was it would increase the number of pulses to move the dish, resulting in more resolution.

To confirm this, I first used the stock location and with the actuator saddle clamp loose enough to allow the arm to slide measured the distance from the clamp to the edge of the actuator arm. The delta from the east most to west most was 7.5". OK should have a delta of 15” or so; all the way out at the end of the extender. But only 8”. Half an inch difference between the two deltas. Couldn’t believe it. Measured again, what a bummer. Extender bracket was a totally worthless concept. Half an inch difference, wow. So took the extender back off for my scrap metal pile. Re-connected the arm to the stock angle iron and started doing the due south satellite.

I had brought the GBOX 3000 out with me and hooked it to the actuator arm. For all my concern about where to set the actuator for the dish pointing due south, all I had to do was point the remote, push the button and run the actuator until the dish aligned with the side of the polar mount.

I plugged my self powered Digisat II meter into one the LNB outputs and discovered I had so much signal I had to attenuate it. Never with my 1M and smaller dishes have I had to do that. Next I swung the azimuth manually for peak signal. This is where I discovered the signal didn’t vary much from satellite to satellite. Must be the small 6 foot diameter and 2 degree resolution Iceberg has mentioned. The signal from one bird drops off as the next comes up. Just a total blur.

At this point no choice but to hook it up to my Pansat 9200HD and see what it said I had. But first I needed to wire a coax from the second LNB output into my switching network. I elected for this dish to use a 22KHz switch. The 0KHz side to my existing 4x1 Diseqc switch and the 22KHz side to the new C band dish. That way all the existing stuff stays the same. Change a couple connectors and ready to go.

So set the best guess on the azimuth and discovered I had 127W Galaxy 13 in my sights. Tuned to LCN, the Louisiana Super Station, and thought of Tron in New Orleans. So I was 8 degrees off. Calculated the inches per degree around the 76mm mast and went out with a ruler and marking pen to set where 118.7 Anik F3 should be located. Checked on the TV and this time was closer, but no cigar. Hit 121 Galaxy 23. Well third time did it and found Anik F3. Peaked that on the TV readout for azimuth and then for elevation. Locked down the adjustments and brought my stuff inside. The rest was an indoor job of locating the satellites and storing their locations into the GBOX.

A number of hours later and a couple mis-steps with wrong 22KHz settings in my channel list on a couple birds, and I had all from 87W to 139W stored and channels scanned into the Pansat.

I like the way the GBOX displays the satellite location by name. After the birds are entered, and doing a manual move the display counts up or down and switches to the name when its hit. But have to say using the name to select which one to move to takes more time than just entering the two digits for the location and hitting OK. Tried the by name way, and you need to scroll through all the choices until you find the correct one. Heck by the time you find it, the antenna would already be in place with the 2 digit method. Also surprised me with how fast the actuator moves from satellite to satellite. But it’s only using 7.5” of the 24” available to swing 52 degrees. I think this dish moves faster than my 1M dishes with Diseqc motors.

After getting all the birds scanned in, my only disappointment was the NASA HD on 137W AMC7. I can’t find usable signal there. Seems NASA needs more power or something. Maybe borrow some from the North West Territories channel from Canada, they had lots.

Tomorrow plan to weed out the channels I don’t want; and try to match what’s left with TitanTV guide. Then a bit of clean up on the coax outside with ty wraps and wire in the living room unit and this project is done.

One day when I have time, I’ll plot out the GBOX count versus the orbit location and see if my notion that it’s a sine wave is valid. But I suspect the signal strength and low resolution of the 1.8M dish won’t prove much. There were some spots that I could have picked half way between two birds and still had a usable signal from both.

So here’s the wrap up pictures and a screen copy of my data for the GBOX.

 

[Tron]

Great review, Wrdavis! Congratulations on the completion of your SD180PM. These are ideal dishes for C-Band in a tight place, and also a great alternative to the ever-popular MiniBUDs. I plan to finish my review of the SD180G (ground mount model) this week...

 

[wrdavis]

Here's a jpg of the parts diagram for the polar mount version for reference.

 

[Corrado]

Thanks for all the great pics wrdavis.

I enjoy seeing these projects coming together, excellent post.

One question perhaps you or Mr.Sadoun can answer... what is the length of the center 3" mast that wasn't used supplied with the SD180PM?

 

[pro96]

Good job .. excellent pictures.

 

[wrdavis]

The 3" mast was 39" high. I cut the triangular mounting plate off and lowered it to 36" for a roof mounting.

 

[Sadoun]

Thanks for all the great pics wrdavis.

I enjoy seeing these projects coming together, excellent post.

One question perhaps you or Mr.Sadoun can answer... what is the length of the center 3" mast that wasn't used supplied with the SD180PM?

The length is 100cm (39").

BTW, I would like to mention that this mast is an optional item and not figured out in the price of the SD180PM. We have shipped one to wrdavis and others who pre-ordered as a "Thank you" for waiting for the back-order and the shipment to arrive.

However, if someone orders the SD180PM and want to add the SP75 (3"dia x 39" mast with base), it will be included at a reduced price.