Slim dish too slim?

[matthewy8]

Hello all, I've got a slimdish with an sl1pll pointed at 97w. The problem is I'm only receiving a few channels maybe 4. I've got a superdish with the fss stacked lnb pointed at 97 also and receive much more than 4 channels. My lo is set to 10750 for the sl1pll. I have the micro HD hooked up to the slimdish and cool sat 5000 hooked to the superdish. I've swapped them same results. So my question is this. Is the small difference in size between the slimdish and the super dish making the difference?

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[cyberham]

91W doesn't have a lot of active transponders at any one time. When you say you receive "much more than 4 channels", are these news feeds? Here I typically might see 4 or so channels but not much more.

 

[matthewy8]

Whoops sorry. I meant 97w big difference. ghead:

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[Anole]

Yes, but what do you mean by "slimdish"?
Show picture, describe, give measurements.

The SuperDish is oval, and has a feedhorn to match its shape.
So, it performs well on 97w.

If your slimdish is oval, the feedhorn on your LNBF is not optimized for that shape.
But I suspect if this is a repurposed dish, you've mounted the LNBF in the wrong position or attitude.

That's an educated guess , without pictures nor sufficient data.

 

[waylew]

I'm guessing he's using a Direct Slimline and agree that the lnbf isn't mounted where it needs to be.

 

[matthewy8]

Yes it is a direct TV dish. The feed horn angle and distance was made to match the original feed horn angle. I used a cardboard template cut to match the original lnb. I will post pictures tomorrow when the sun comes up. It did fine on 83w as well. The dish is about an inch shorter and about two inches narrower than the super dish.

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[Anole]

Members have used the DTV Slimline dish, and reported acceptable performance with round-horn LNBFs.
?

 

[matthewy8]

Here are the pictures requested.

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[SatelliteAV]

The new LNBF appears to be sitting too high. Measure on the original from the tube insert to the center of the middle LNBF then duplicate the same height on the replacement.

The dish is small, but you will receive most 97w transponders during clear conditions.

 

[matthewy8]

You are right! I don't know how I missed that one. It is exactly 1" higher. I will move it and try again. Thank you for pointing it out. About how many channels should I expect to see?

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[Anole]

The change should also make the mount elevation scale read closer, as well. :up

Edit: the template idea was a good one.
?Wish more people did something like that.

 

[matthewy8]

Well, I just moved it down 3/4 inch did a blind scan and nothing showed up this time. I must have been in a good spot before. I did a blind scan this morning before I messed with anything and got 16channels. Don't know why I didn't yesterday.

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[Anole]

Did you also change the elevation on the mount after moving the LNBF height?
?

 

[matthewy8]

I guess I dont understand why I need to move the elevation on the mount if I'm lowering the whole mount itself, its bottomed out in its scale right now. I just measured the distance between the feed horn and dish. Its about 2 inches longer than the original lnb distance. So I need to shorten that up.

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[Anole]

The "mount" holding the dish to the pole.
Not the bracket holding the LNBF.

And, that 2" error you found, means you are way out of focus.
?Gotta fix it, too.

 

[matthewy8]

OK got it. If I shorten the arm won't I need to raise the elevation of the lnb back up?

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[Anole]

I suggest you just start over.
Here are clear instructions for making a template:
http://www.satelliteguys.us/threads/147855-convert-superdish-to-true-fta-use?p=1540313#post1540313

?

 

[matthewy8]

OK, I will go back over the instructions again. Thanks.

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[matthewy8]

OK I got it. I had to shorten the arm by 1 11/16" and lower the elevation a few degrees like u suggested. That got me 167 channels and 54 radio stations. Is that about what I should expect to see on 97?

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[SatelliteAV]

With the LNBF mounted too high, the reflector was not correctly focusing all of the reflected signals. Much of the reflected signal was missing the LNBF!

You are correct! The LNBF will not receive the reflected satellite signals anymore. The LNBF is now in the correct position to collect all of the reflected signals when the dish is correctly aimed.

Moving the LNBF down into the correct position, the signals collected from the reflector will now be focused into the correct "Sweet Spot". If you only move the LNBF down into the "sweet spot" without correcting the dish elevation setting, the reflector is no longer aimed at the satellite.