Do I need the spacer with a KU LNB on a 6' solid Channel master dish?

[ken2400]

In my haste I did not install the spacer when changing out a KU LNB. I replaced a 1209HA Norsat LNB with an Primestar single on a 6' Channel Master solid dish.

I am receiving Cozi at 103W fine with a 16 db SNR?
The spacer is about 1/2" and is shaped as you see in the picture.

I am keeping it just in case I need it someday.
Thanks

 

[FaT Air]

By spacer, you mean the silver colored piece with the screws?
If so, that part allow skew adjustment IIRR. Maybe the primestar has a 'different looking' skew adapter?

 

[ken2400]

By spacer, you mean the silver colored piece with the screws?
If so, that part allow skew adjustment IIRR. Maybe the primestar has a 'different looking' skew adapter?

Ya the silver part. I can turn the whole LNB and feedhorn at the black ring that hold it onto the dish.
I need to see what a Primestar LNB looks like where it attaches to the feedhorn.
Maybe this is just spacer and I might be more turned if I placed it in there?
I should be it back so it does not get lost and for the sake of testing.

 

[FaT Air]

I've only seen those 'spacers' on the elliptical primestar dishes. Can't rotate that feed, it's bolted solid. Only way to skew is the LNB on the feed.
Your feed doesn't need it as the feed will skew in its holder,
I've got a few of each style. Elliptical and 'normal'.

 

[danristheman]

Those were also on DN superdishes I might have one I would have to check when I get back home. Look for an old DN superdish.

 

[beavs2112]

In my haste I did not install the spacer when changing out a KU LNB. I replaced a 1209HA Norsat LNB with an Primestar single on a 6' Channel Master solid dish.

I am receiving Cozi at 103W fine with a 16 db SNR?
The spacer is about 1/2" and is shaped as you see in the picture.

I am keeping it just in case I need it someday.
Thanks

Yes you need the "spacer". Its a waveguide polarizer. Its job is to convert the circular polarized rf from the feedhorn to the linear polarized rf needed by the lnb. It will probably give you 2-3db of signal back.
It goes on only in one direction. The circular hole goes toward the feedhorn & the rectangular hole goes toward the lnb.

 

[Magic Static]

Was there something wrong with the Norsat LNB? I really don't think the Primestar LNB is a better choice than the high dollar Norsat PLL unless you have an issue with powering the LNB.

 

[beavs2112]

ken2400 an addition to my post above. I'm assuming the hole on the back side (away from the dish) of the CM feedhorn is round. If it isn't then you don't need the polarizer.
The 2 pics (its a prodelin polarizer but that doesn't matter) show better what I meant about which side goes towards the lnb etc.

If its working ok now you can get away with leaving it off ..... if its a long drive back to re-install it etc. But if you are in the area I would recommend putting it back on. As you know with ku signals they are subject to rain fade etc. I'd want every db of signal I could get so it might be worth the 2-3db to put it back on.

 

[ken2400]

Was there something wrong with the Norsat LNB? I really don't think the Primestar LNB is a better choice than the high dollar Norsat PLL unless you have an issue with powering the LNB.

Well it and the X2 Premium mini went out for the guys I help during a lighting strike. I am bumming the Norsat LNB stopped working. I did think it would be a better LNB. I do get both H + V now with the Primestar LNB. I wish I wrote down the SNR before the strike. It is 16 now.

 

[ken2400]

ken2400 an addition to my post above. I'm assuming the hole on the back side (away from the dish) of the CM feedhorn is round. If it isn't then you don't need the polarizer.
The 2 pics (its a prodelin polarizer but that doesn't matter) show better what I meant about which side goes towards the lnb etc.

If its working ok now you can get away with leaving it off ..... if its a long drive back to re-install it etc. But if you are in the area I would recommend putting it back on. As you know with ku signals they are subject to rain fade etc. I'd want every db of signal I could get so it might be worth the 2-3db to put it back on.

Ya I will get it back on. The next time I get up there and note the difference in SNR. Thanks for the pics.

 

[Cham]

I get 12.5dB S/N on the 11760 TP (COZI) with a 4', so 16dB should be close for 6' since it is 2.5X the surface area. Maybe the spacer is needed for circular?

 

[ken2400]

ken2400 an addition to my post above. I'm assuming the hole on the back side (away from the dish) of the CM feedhorn is round. If it isn't then you don't need the polarizer.
The 2 pics (its a prodelin polarizer but that doesn't matter) show better what I meant about which side goes towards the lnb etc.

If its working ok now you can get away with leaving it off ..... if its a long drive back to re-install it etc. But if you are in the area I would recommend putting it back on. As you know with ku signals they are subject to rain fade etc. I'd want every db of signal I could get so it might be worth the 2-3db to put it back on.

Just talked to the guy at the station and Cozi went out in a heavy rain.
Need to do more fine tuning with the dish.
So I need to put the spacer back in and if it does not work with Primestar LNB I will have to get another LNB.

Which LNB should I get?
Thanks

 

[beavs2112]

Which LNB should I get?
Thanks

I'm quite fond of Norsat PLL LNBs. Yes they're expensive but its worth it in my opinion.
Also NJR (New Japan Radio) LNBs are ok. In my experience they have less gain than an equivalent Norsat but they are less expensive.
I see you lost a Norsat recently but it isn't always the LNBs fault if lightning causes a surge. Often a satellite dish install is not properly bonded or grounded.

 

[ken2400]

So I reinstalled the prodelin polarizer and it did not make much difference SOOOO I moved the dish a bit and now am up at 18 CNR.
Next question can strap on KU LNB like
Avenger PLL321
Thanks

 

[ken2400]

I was wondering I could modify the LNB holder to use a cheaper LNB? The one you see on 36" dishes.
Thanks

 

[Cham]

I am using a regular LNBF on a channel master 1.2m using the original feedhorn clamp. It doesn't fit properly and needs to longer screws to reach. Maybe someone makes a 40mm holder for these dishes?

 

[hank123]

I am using a regular LNBF on a channel master 1.2m using the original feedhorn clamp. It doesn't fit properly and needs to longer screws to reach. Maybe someone makes a 40mm holder for these dishes?

Did it change your F/D?

 

[RimaNTSS]

Maybe someone makes a 40mm holder for these dishes?

I recently made new holder for such a dish.... HERE.

Did it change your F/D?

It is impossible to change F/D ratio of the dish, does not matter what LNB-holder is installed.

 

[hank123]

I could be out in far left field, If you install a different LNB then it will change the F/D. The stock LNBF is set for the highest gain. A Universal LNBF will sit different.
Your set up is sweet! Something I have been looking for.'
Thanks for sharing

 

[Cham]

Mine works fine as-is, only changes the focus maybe a couple of millimeters so I aim the dish less than a half a degree lower to compensate. Don't need multi-LNBFs here but I certainly acknowledge the fine engineering done by RimaNTSS to allow for this. If the original feed horn had dual polarity I would likely use it instead as I have some Ku LNBs kicking around.
Actually I have a C-band LNBF and clamp that was used on this dish at one time before I owned it; thinking this setup would cause 2-3 degrees difference in offset

I recently made new holder for such a dish.... HERE.