T90 dish and bandstacked LNB's?

[MetaMan]

A multi-part question:

Is their a practical way to get a T-90 Toroidal to work with Dish Pro (band stacked) or Dish Pro Plus (Double Stacked?) compatible receivers?
(i.e. Is there an external bandstacker available that is compatible? Or does one have to try using modified Dish bandstacking LNBFs, which I think are not reversed like toroid specific LNBFs?).

I suspect one could use two DP34s or two DP44s in parallel to multi-switch in both polarities of the dual LNBs but this would require dual cable runs to each Dish dual tuner DVR. I want my cake and to eat it too. Can this be made to work?

Might you not actually need a 6x4 multiswitch and a DP44 to handle the feeds from all the LNBFs and more still support more than 2 Dual Tuner Receivers?

 

[pendragon]

Is their a practical way to get a T-90 Toroidal to work with Dish Pro (band stacked) or Dish Pro Plus (Double Stacked?) compatible receivers

There are some Rube Goldberg solutions that would also work, but the easiest approach is to pop the casing and cap off a DishPro LNBF, cut the glue away from the dielectric insert in the throat and rotate it 90 degrees. That will turn the LNBF into a reverse circular LNBF. This way you can employ any switching solution and receiver that you could use in a non-T90 configuration.

 

[MetaMan]

Thanks for the advice, sometimes I can get to close to the problem to recognize a simple alternative.

Just to clarify a point. Since DishPro LNBFs are circular polarized LNB's and not linear polarized, you mean flip the dielectric polarizer over, not rotate 90 degrees, right?

Would this still work for the 118.75/119 combo LNBFs?

 

[pendragon]

If you look down the throat of a factory-fresh DishPro LNBF, the dielectric plate will be oriented vertically (the probes at the end of the waveguide are offset by 45 degrees each way). Remove the plate and orient it horizontally. That is why I said 90 degrees.

I haven't examined a 118.7/119 combo LNBF, but I wouldn't be surprised if it's similar. Looking first isn't going to disable the LNBF.

 

[MetaMan]

You're referring to DishPro LNBFs not DishPro Plus LNBFs right?

Once the mod is done, and the signal sent through a switch I'm still going to have to run two lines to a dual tuner box the the 722 or 922 right? Wouldn't I need DishPro Plus LNBFs to make it work over single run to tuner (the Plus in DishPro Plus)?

 

[pendragon]

I may not be current with the latest DN LNBF offerings, but I thought the only DishPro Plus LNBFs were dual or triple satellite designs. These cannot be used on a T90 because the spacings are different. So you're kind of stuck with plain DishPro LNBFs, one for each bird.

This doesn't mean you HAVE to run two cables all the way to your receiver. Depending on how many receivers you have, some solutions will be better than others. You'll likely end up with a switch to collect all of the LNBFs for DN on your T90. A DPP 44 can be used to drive one cable each for up to four DPP-capable receivers, including the 722 and 922.

 

[MetaMan]

You're right, of course. Just getting up to speed. The DishPro Plus LNBFs are just a dual or triple config. I mistakingly thought you required DPP LNBFs as well to use DPP receivers. I now know the DPP 44 can work with DishPro LNBFs.

In this scenario (DP LNBSs -> DPP44 -> DPP compatible Dual Tuner Receivers), is there any reason to use the moded dual DishPro LNBFs (DN128)) vs the Single DishPro LNBFs? Doesn't the DPP44 internally destack the DP LNBF stacked polarities before it switches and restacks for dual tuner receivers?

 

[pendragon]

You only need one output per LNBF for the DPP 44, so it doesn't matter which DishPro LNBF you use.

 

[MetaMan]

Pendragon: We have a problem.

Picked up 3 Dish Pro dn128 LNBF to do the conversion but the throat only has a cast aluminum polarity splitter. Kind of a triangular stepped plate with 2 antennas on either side that are on two circuit board fingers that approach the splitter plate.

Which models did you use? I doubt the T90 LNB holders could ever get around the plastic case even if I am able to figure out the fix.

The DP44+ Pro switch can only handle 4 inputs or both sides of two non-Dish Pro LNB's so I need this fix if I'm going to get 110/119/128 on the T90.

Any more idea's?

 

[MetaMan]

Photo of opened DishPro LNBF (DN128)

Here is a photo of what I'm talking about.

 

[whatchel1]

129 not 128

Pendragon: We have a problem.

Picked up 3 Dish Pro dn128 LNBF to do the conversion but the throat only has a cast aluminum polarity splitter. Kind of a triangular stepped plate with 2 antennas on either side that are on two circuit board fingers that approach the splitter plate.

Which models did you use? I doubt the T90 LNB holders could ever get around the plastic case even if I am able to figure out the fix.

The DP44+ Pro switch can only handle 4 inputs or both sides of two non-Dish Pro LNB's so I need this fix if I'm going to get 110/119/128 on the T90.

Any more idea's?

May be a typo but it is 129 not 128 for the 3rd sat. Use 3 of the single DPP LNB's and clamp around the throat of them using something to clamp to throat. Or one other way is to epoxy the body of the LNB to the throat clamp with it center w/in the clamp will also work. Have fun adapting the T90. Is the mount on the T90 scewable to angle the dish enough to catch all 3 sats while centered across the front of the dish?

 

[MetaMan]

Part Number mispoken

Yes, I was getting the DN128 LNBF mixed up with SAT 129.

You refer to the DPP single LNBF, I think you're referring to the DP (DISH Pro) LNBF. The DPP (DISH Pro Plus) LNBF such as the DP Plus 1000.2 LNBF has an integrated stacked LNBF with a Dish Pro Plus switch. I have not be able to find a single DP LNBF from my distributor, just the dual DISH Pro LNBF (DN128).

I think, generally, most people don't understand the difference between DISH Pro (DP) and DISH Pro Plus (DPP) technology.

 

[whatchel1]

YES

Yes, I was getting the DN128 LNBF mixed up with SAT 129.

You refer to the DPP single LNBF, I think you're referring to the DP (DISH Pro) LNBF. The DPP (DISH Pro Plus) LNBF such as the DP Plus 1000.2 LNBF has an integrated stacked LNBF with a Dish Pro Plus switch. I have not be able to find a single DP LNBF from my distributor, just the dual DISH Pro LNBF (DN128).

I think, generally, most people don't understand the difference between DISH Pro (DP) and DISH Pro Plus (DPP) technology.

The singles are Dish Pro. The multiples are the Pro Plus. You will need the individuals since you will have to spread them apart differently than the duals & triples for the Dish dishes.

 

[pendragon]

I gathered somewhere around 50 of the DishPro LNBFs (dual outputs) that were designed for one orbital location. Only one had an aluminum stepped plate and it looked much older than the rest. I never spent any time on it because it was very noisy. The stepped plate looks like it would require fairly delicate surgery to convert to reversed polarity.

See the attached photo for a comparison of these two types. The one on the left has the aluminum stepped plate while the one on the right has a plastic dielectric plate. Note the stepped plate LNBF is much thicker at the base, but inside the plastic shell this may not be apparent. However on mine there are two little screws mounting each F-connector for the stepped plate version, while the dielectric plate unit uses only a nut on the connector itself. As I have only one of the stepped plate models, I can't say whether these characteristics are definitive. However all my dielectric units are alike and are certainly easy to modify.

 

[whatchel1]

Why?

I gathered somewhere around 50 of the DishPro LNBFs (dual outputs) that were designed for one orbital location. Only one had an aluminum stepped plate and it looked much older than the rest. I never spent any time on it because it was very noisy. The stepped plate looks like it would require fairly delicate surgery to convert to reversed polarity.

See the attached photo for a comparison of these two types. The one on the left has the aluminum stepped plate while the one on the right has a plastic dielectric plate. Note the stepped plate LNBF is much thicker at the base, but inside the plastic shell this may not be apparent. However on mine there are two little screws mounting each F-connector for the stepped plate version, while the dielectric plate unit uses only a nut on the connector itself. As I have only one of the stepped plate models, I can't say whether these characteristics are definitive. However all my dielectric units are alike and are certainly easy to modify.

Now explain to me why a toroidal needs to have reversed polarity for E*? You do know the E* use circular not linear polarity? So I don't understand why the toroidal dish would make any difference?

 

[MetaMan]

Why Reversed with a Toroidal

A common question but the answer is looking you in the mirror.

The circular polarized signals greatly simplified installation as they no longer required on axis vertical and horizontal alignment of the LNBs like Linear polarized signals. You can basically aim the dish and not worry about LNB alignment. In a toroidal, you can flip linear polarity by rotating the LNB 90 degrees in the holder, however the factory toroidal LNBs make this unnecessary so more LNB's can be installed close together. Circular polarized LNB's are a completely different story.

With circular polarized signals, the radio wave travels in either a clockwise (Right) or counterclockwise (Left) motion. Whenever a signal bounces of a reflector, the signal flips or mirrors so the right hand polarity signal becomes left and vise versa. In a single reflector dish (i.e. DISH 1000+) the LNB's are designed to take the sic "flipped polarity" signal from the original beam and Block Feed it to the right frequency depending on the receiver and/or switch signal.

With toroidals, there are 2 reflectors, a primary and secondary. The primary reverses the signals circular polarity and the second reflector flips it back. The problem is normal everyday circular LNBs are designed to receive this reversed polarity signal (off one reflector). With a toroidal circular LNB, they must use the actual polarity as beamed and convert it to the normal or reversed polarity of the standard LNBs the the receivers can locate the signal in the right frequency.

Wave Frontier sells corrected circular and Linear LNBs, but not band stacked LNBFs like the DISH Pro LNBs, hence the desire to modify one to work.

I've enclosed an image of a T-90 to let you get a better idea.

 

[pendragon]

You only need reversed LNBFs for circularly polarized signals with a dual reflector. Linear LNBFs work the same on single and dual reflectors.

 

[VinceT3]

Someone explained how to do this.. needed some old lnbs (which I picked up) and some additional parts (which again I picked up) .. and after all that I took my T90 down and switched to directv.. lol.. so never got to use it..

 

[MetaMan]

Pendragon:

All the LNB's my distributor shipped me are of the stepped plate kind (the left ones in your picture). Been trying to find a DishPro PN: 151019-NS but find a distributor up here stocking them. (ideas?)

The case on mine is quite wide on the neck, basically wouldn't work on the T90's LNB holders without removing them from the case. Do the one ones on the right in your picture which you modify have a thinner neck or do you have to mount them outside their cases also?

 

[whatchel1]

Claude

Pendragon:

All the LNB's my distributor shipped me are of the stepped plate kind (the left ones in your picture). Been trying to find a DishPro PN: 151019-NS but find a distributor up here stocking them. (ideas?)

The case on mine is quite wide on the neck, basically wouldn't work on the T90's LNB holders without removing them from the case. Do the one ones on the right in your picture which you modify have a thinner neck or do you have to mount them outside their cases also?

PM or email Claude Greiner (if I misspelled Your last forgive me) at DishStore here. See what he can do. Yes I knew that a tor double bounced the signals. Just didn't know that the 2nd bounce f'd w/ circular signals. The tors I've worked w/ make the T-90 look like a toy. They were 10 ft top to bottom and 30 something wide and the LNB's face the surface of the dish.