Better setup for my 91/97?

[natsu]

I currently got a 36" dish with a single LNB holder that is holding 97 in it. Then attached to it, I taped another LNB for 91 and its working good for the past many many months....

But this is not permanent, is there a special bracket for 91, 97? Or at least something that I can setup with no need of tape? LOL

[Terryl]

Take a look at one of these puppies.


http://www.thesatelliteshop.net/magic-bracket-iii-connect-3-lnbs-extend-for-extra-lnbfs-p-663.html

If the dish is skew-able you can use some aluminum angle and fix the LNB's at a 6 degree spacing.

[snake]

that is good ,6 degrees apart i would not have thought of that working being so close .i have eliptical 18x24 inch and had 119-110-91-82 on it ,i taped lnb to outside of 119 and picked up 129.i would imagine you could get a bracket for this .

[natsu]

Acutally currently I got my 2 LNB's stuck together lol, meaning they are RLLY close to eachother :P I am getting on average about 70% quality even in sunny days, lol I am wondering why :P I can probebly get a photo up here by tommorrow. ill show u what I mean :P Should I get something like this?



http://cgi.ebay.ca/DUAL-SECOND-LNB-SATELLITE-DISH-LNB-BRACKET-FTA-33-39-/220510326848?pt=LH_DefaultDomain_2&hash=item3357709040
http://cgi.ebay.ca/30-inch-Dish-Dual-Lnb-Mounting-Bracket-Adatapter-FTA-/310093701515?pt=LH_DefaultDomain_0&hash=item483306618b

[dishuser]

you need to kill live links

[Terryl]

Thanks Dish I fixed it for him...


Natsu, the second one wold work better as it has spacing and skew adjustments.

[natsu]

I actually was editing them the same time u were lol :P nvm now

so if I get the second one, it would work for 91/97?

--EDIT1--

Does this work for 91? Cuz my current one does not have a casing on it lol :P ill show u wat i mean in the picture later


http://cgi.ebay.ca/DUAL-DSS-CIRCULAR-LNB-DISHNETWORK-BELL-DIRECTV-FTA-LNBF-/220492360298?pt=LH_DefaultDomain_2&hash=item33565e6a6a

--EDIT2--

Here are some pics



http://i54.tinypic.com/ih17go.jpg
http://i54.tinypic.com/2m2dr40.jpg
http://i54.tinypic.com/2nsykad.jpg


The one in the main bracket is 97 the one attached to the side using tape is 91

[WillDekkard]

Another possible option would be a Direct TV World Dish. It is made for a 6 degree spacing for 95/101. You would need to flip the holder brackect around for a 97/91 setup.
http://www.satfix.net/attachment.php?attachmentid=10889&d=1310400300

[natsu]

I don't want to change dish's I just want the best possible signal and strudy way to get 91/97

[jvvh5897]

I largely use iron pipe hanger strap to build my brackets--the holes in it allow you to use nuts and screws and it bends easily to adjust position but not so easily that once you have it set that it moves without some real force (though a couple of wind storms bent it and I think a bird landed on it once with enough force). If needed you can cobble together a wooden support to screw the strap to and attach to LNB arms in creative ways.

[RimaNTSS]

I like self-made feeds. Any metal-workshop can make them, just give them idea.

[Terryl]

Did anyone stop to think why do they (the dish designers) use plastic for their LNB mounts?

It's not to save cost as aluminum or cast pot metal would work just as good, but its to keep the amount of metal hanging out in front of the dish down to a bare minimum.

This is to keep the unwanted signal reflections out of the picture, any reflection of signal by any metal bracket or mount would/could cause a decrease in the main signal, this is due to phase cancellation of the main and reflected signals, the reflected signal is 180 degrees out from the main, you mix the two and you attenuate the main, this could be why some have low signals on the multi LNB setups using a metal multi LNB bracket.

This is not going to happen to all installs, this is just a possibility, it would be better to use plastic and glue to make up a mount if the dish is a prime focus (LNB is centered to the dish) and not an offset (LNB(s) are off set to the bottom) type dish.

On a prime focus center mounted LNB type dish the more stuff you hang out in front the less signal gets by to the main reflector.

[WillDekkard]

Did anyone stop to think why do they (the dish designers) use plastic for their LNB mounts?

It's not to save cost as aluminum or cast pot metal would work just as good, but its to keep the amount of metal hanging out in front of the dish down to a bare minimum.

This is to keep the unwanted signal reflections out of the picture, any reflection of signal by any metal bracket or mount would/could cause a decrease in the main signal, this is due to phase cancellation of the main and reflected signals, the reflected signal is 180 degrees out from the main, you mix the two and you attenuate the main, this could be why some have low signals on the multi LNB setups using a metal multi LNB bracket.

This is not going to happen to all installs, this is just a possibility, it would be better to use plastic and glue to make up a mount if the dish is a prime focus (LNB is centered to the dish) and not an offset (LNB(s) are off set to the bottom) type dish.

On a prime focus center mounted LNB type dish the more stuff you hang out in front the less signal gets by to the main reflector.

Thanks Terryl, very good info there. I noticed that even "Magic Brackets" have plastic LNB holders as well. There is always a very good reason for everything, I'm glad you pointed out this one!

[natsu]

Does this work for 91?


http://cgi.ebay.ca/DUAL-DSS-CIRCULAR-LNB-DISHNETWORK-BELL-DIRECTV-FTA-LNBF-/220492360298?pt=LH_DefaultDomain_2&hash=item33565e6a6a

or not?

[WillDekkard]

Does this work for 91?


http://cgi.ebay.ca/DUAL-DSS-CIRCULAR-LNB-DISHNETWORK-BELL-DIRECTV-FTA-LNBF-/220492360298?pt=LH_DefaultDomain_2&hash=item33565e6a6a

or not?

Yes, that one will work for as it states for Dish Network, Bell and DTV. It will work for 91.

[natsu]

k thanks, as u can see from my pic, my current one has no casing lol, just the metal part :P

[jvvh5897]

Did anyone stop to think why do they (the dish designers) use plastic for their LNB mounts?

It's not to save cost as aluminum or cast pot metal would work just as good, but its to keep the amount of metal hanging out in front of the dish down to a bare minimum.

This is to keep the unwanted signal reflections out of the picture, any reflection of signal by any metal bracket or mount would/could cause a decrease in the main signal, this is due to phase cancellation of the main and reflected signals, the reflected signal is 180 degrees out from the main, you mix the two and you attenuate the main, this could be why some have low signals on the multi LNB setups using a metal multi LNB bracket.

This is not going to happen to all installs, this is just a possibility, it would be better to use plastic and glue to make up a mount if the dish is a prime focus (LNB is centered to the dish) and not an offset (LNB(s) are off set to the bottom) type dish. On a prime focus center mounted LNB type dish the more stuff you hang out in front the less signal gets by to the main reflector.

All good and valid points--microwaves have many aspects that even electrical engineers call magic. But, have you ever seen an offset dish that is for internet use?--they hang the upconvert power amp at the focus with all its heat dissipation fins, splitters to feed the LNB on the receive side, the odd table that everything sits on. Compared to that, our brackets are pretty insignificant. Add to that the fact that for offset feed dish the LNB only blocks a part of the dish at the edge--our LNBs have a dropoff of response for the edge of the dish (once I duplicated the curve of a 18 inch provider dish with a sheet of 11 by 14 inch poster board covered with AL foil and even with the poor surface and reduced size I got pretty much the same signal as with full dish--the LNB just does not see the full dish area with equal response).

Sure with a prime focus dish things are different, but for offset dish I think you can get away with lots of stuff.

Oh, and the plastic LNB supports--I think they are just cheaper to make--If made of metal, everything would be behind or around the metal of the LNB feed and casing (you do know that there is lots of metal in the LNB too, yes?), pretty much no change in what is blocked or re-radiating.

[natsu]

Just curious, am I able to attach 82 to my 91/97 on a 36" dish? or will that not work?

[jvvh5897]

Will you get signal?--sure, the circular polarized signals have easier time than the linear dealing with the off-axis stuff. You loose a little more signal the further you get from the center of the dish's pointing, but the provider signals are stronger to begin with.

Basic rule of thumb, the signal strenth drops by the cosine of the look angle required between center look angle and off-axis look angle (just get the AZ for the two sats and subtract). Distance between LNBs is tangent of difference of look angles then times the focal distance for the dish.

But just because you can get good signal does not mean that you can receive the signals on the 82 bird--they are scrammbled. Topic for other sections. Some are HD--not all receivers can deal with those signals either.

[Terryl]

It's not the blocking or re-radiating but the hardware spurious emissions that could be created, you should see the hardware radiation that is produced around the antenna hardware on anything above 5 GHz, its a mess when a screw or mounting bracket that just happens to be of the right length starts to radiate when its in resonance with the main frequency, I've had 7 GHz hardware cause spurs up on 21 GHz stuff, it can get to be a mess.

I've got a couple of internet dishes I'm trying to mod for a data link, I wish I still had my HP spectrum analyzer...

As far as 82 on the 36" dish it would depend on the over all receive beam width of that dish, you could hang the LNB out at the right spot but not get enough signal to do any good. (I agree with JVH on this)