Maybe I need a new dish for my setup?

[oldsmobile]

I bought a Globecast setup cheap locally, and after much trial and error, I was able to get it locked onto 97W. I'm in Harrisburg, PA, at 40.3074 lat and -76.9003 long, per sites. I liked what I was getting into, and decided to introduce a motor into the mix. I bought a MicroHD receiver and a Moteck SG2100 to move the dish.

Try as I might, I cannot get this combination to get anything. I am baffled and at least somewhat frustrated because I don't know what I'm doing (or doing wrong). But tonight, with my latest trek up the ladder to adjust, I noticed something. The shaft of the motor supports the dish fine at the top, but I can change the angle of the dish up by a few degrees, and then drop it back into place. (I don't actually drop it; I guide it back to its stop.)

Is that normal? Do I need a dish or dish mount that fits onto the dish motor shaft more precisely? I've enclosed pics, because hey, why not. Maybe one of you experts will instantly see the problem that I cannot.

 

[oldsmobile]

Oh, and sorry about that Great States pic. Unrelated. I wasn't paying attention to upload, and then I thought I chose not to upload it, and here it is. Oy vey.

 

[Anole]

Your words confuse me..but....
Does the dish mount not clamp tightly to your motor shaft?
If that's the case, we generally take a short length of two inch (?) plastic pipe, slit it up the side, and push that onto the motor shaft to take up the slop.
'
?Would be nice if you enclosed a non-close up shot of the dish to verify what you are talking about.

 

[oldsmobile]

I appreciate the response. I have a hard time describing certain things. Yes, the dish mount has some slop in it--it does not clamp tightly to the motor shaft. In the daylight, I shall take further photos and see if I can demonstrate the movement that's possible.

 

[oldsmobile]

Okay, here are two (hopefully better) photos showing the motor shaft from underneath. The shaft accepts a through-bolt at the top which acts as a pivot, maybe unintentionally? One photo shows the assembly at rest and the other shows the assembly moved by hand to the mechanical limit. I hope I'm describing the gap so someone can tell what I mean.

 

[oldsmobile]

And here are photos showing the setup, and a closeup of the maker's mark. It's a Channelmaster dish. I appreciate any ideas.

 

[Anole]

Very good pictures, showing the problem clearly. :up
Motors come with two diameter shafts, depending what dish they will be used with.
Your motor has a 42mm or small shaft.
.
For heavier dishes meant to be mounted on larger poles (or commercial dishes) some big motors have 50-55mm shafts.
As I mentioned above, the usual fix is to shim the shaft with a piece of plastic pipe, slit lengthwise.
That'll take up the slop while keeping the shaft centered in the mount bracket.
.
?then the only remaining question is whether your motor can handle the heavy mount & dish?
.
edit: oh, a 75e dish! Nice choice.
I think your motor should do the job, but get feedback from someone who owns one to be sure.
?.

 

[T4Runner]

I would highly suggest if you are going to keep that dish then you need two braces on the mast to keep it steady. Otherwise it's going to move the mast on you as the weight shifts when the dish moves.

Here's what Anole was talking about:








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[bigg t]

I think I used the clamping part off of an old DN mount . Then I only had to shore that to take up the slack. The 75E works pretty good on a motor but it is kinda heavy for the 2100. You'll need to keep an eye on the backlash as time goes by if you move yours as much as I do.

 

[oldsmobile]

Update - pipe and supports added



I truly appreciate the expert eyes and the advice to put a piece of pipe in the assembly to take up the slack. I did so (and bonus--I already had a piece of pipe serving no other purpose since the last plumbing job, so it cost me nothing extra). I had also found a dish mount with support legs at a yard sale for fifty cents and picked it up, thinking I'd find a use for it. After being politely informed that it'd be a good idea to bolster this thing, I was really happy I'd bought that hardware.

So, I can report some success. Although my true south satellite is variously listed as Galaxy 4r at 76.8W and as Echostar 1.4.8 at 77W, neither had specifications in my microHD receiver. I wasn't able, yesterday, to figure out how to get the specs for either bird and add them to my dish. I chose the closest one already in the receiver's listings, which was AMC6 at 72W. I had to change the dish elevation from 24 degrees up to 26 degrees to get anything at all, but when I made that change, I was able to pull in NBC feeds at ~75% signal quality.

Now I know my hardware is good. From my limited experience, I thought that the microHD would be able to find the other birds via USALS with much less work on my part. But moving the dish via the motor control on the receiver gave me zilch. I can think of two likely possibilities: either I need to establish 77W and re-aim, or I need to fine-tune at 72W for best signal. What's the recommendation?

 

[jorgek]

Is mast/pole perfectly level and plumb? This is critical to a motor setup. If its not you will miss all the other sats on the arc. USALS is very accurate so make sure that your LAT and LONG inputs to the receiver are accurate as well.

You shoud be ok with peaking the dish on 72W.

 

[oldsmobile]

I spent more time yesterday ensuring perfect plumb after I installed the bracing legs. I have a Harbor Freight Dial Gauge Angle Finder and I had it dead on at the top and two sides, and I was fairly confident that it was plumb. I will get out the ladder and check my work again. I'm optimistic...finally. I had inquired with a local satellite firm about doing this, and they estimated $200. I didn't want to spend that much for something I should be able to learn.

 

[northgeorgia]

Yep and just to clarify a couple of things jorgek said: after you make sure the past/pole is level and plumb, do the same for the actual motor mount itself. The first several months, it was slightly off and I couldn't understand why. Then I realized I hadn't bolted the motor to the mast at a perfect 90 degree angle. I did that, adjusted the elevation of the dish slightly, and boom -- perfect tracking.

When your LAT & LONG are set in the receiver, go ahead and drive the dish with USALS to 72W before peaking it (in other words, don't try to peak it at "0" position or true south -- then it will throw everything off for sure).

 

[jorgek]

One more important note, do not over torque the bolts that hold the motor assembly to the mast. I did which deformed the mast and threw the entire dish and motor out of plumb. Result was poor tracking of the arc. Took me a while to figure it out. I replaced the mast and now the tracking is vertually perfect from 30W TO 125w.

 

[. Raine]

You may want to check the skew setting on the dish too, if that dish was setup as a fixed dish before. I think with the motor the dish shouldn't be skewed at all, the motor will take care of that. I don't know enough about the 75 E to tell you from your pictures if it's set right or not but that could mess you up if it's wrong. I'm positive sure that someone on here would be able to tell you how to check if it's right or not.

 

[turbosat]

Yup-he needs to be sure the lnbf is at the zero mark before tweaking anything else.

 

[. Raine]

Yup-he needs to be sure the lnbf is at the zero mark before tweaking anything else.

Thanks for mentioning the LNBF skew, Turbosat. I'd completely forgotten about that. I was thinking of the skew setting on the dish itself, it looks like in one of his pictures that it has a skew setting on the back of the dish, but I'm not sure if it is or not.

 

[oldsmobile]

after you make sure the past/pole is level and plumb, do the same for the actual motor mount itself.

That is some sage counsel, my friend. Thank you for making sure that I didn't overlook that. I didn't even give it much thought, but when I got up there with the angle finder and tools, sure enough, there were adjustments needed.

I got back up to the dish a couple of nights ago, and tinkered with the aim and plumbness. It's slightly frustrating that when I tighten a fastener, it tends to change the geometry of the work. But I now get everything from 72 west to 123 west.

Oddly, I cannot get anything under 72 or 125 or above.



A Raine: The dish is set at 90 degrees on the back marker. When I had it pointed only at 97W, that was at a different setting that I don't have in front of me right now. But when it's pointed at 72W, which is what I'm using as true south, it's not skewed either way. It gives me good signal strength from 72 up to 123.

So, it's well on its way to being all set up properly. I wonder why I have these limits, so I'll have to do some more ladder time and see what new stuff I can learn.

You guys are awesome. Thanks for helping a neophyte. Once I get it perfect, I'll have to post exactly what equipment and settings I have so as to add to the knowledge base.

 

[jorgek]

You mention "Oddly, I cannot get anything under 72 or 125 or above."
Does that mean the dish does not move below 72 and does not move beyond 125 or you do not receive any sats outside those limits?

One more important note.
When you drive the motor/dish assembly to the "0" reference mark with USALS, the dish/motor assembly must be pointing at your true south. If it is not aligned with true south you will not track the arc properly.

 

[northgeorgia]

I bet the dish elevation is slightly off. Try 125W and move the dish slightly up and then down by gently pushing one hand against it.

Edit: that's true (what jorgek said). In addition, the skew should be at 0, not at 72W but with the motor at "0" position (true south). The motor will adjust the skew automatically (although granted, it won't be very much for 72W).