2º Separation?

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RedSavina

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Aug 19, 2005
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As a (current) Dish Network subscriber for over 10 years, I have not paid much attention to DirecTV. While researching their offerings and equipment today I leaned that the Slimline AU9 dish receives programming from 99/101/103/110/119. Those first three satellites are only 2º apart. I'm sure there is a reasonable explanation for this - can anyone enlighten me?
 
when you look beneath the surface . . .

Makes it easier to hit. Also I think 99 and 103 are KU Band.
Having them all together, makes for a one-dish solution, which they like.
(less expense to install, etc)
And I believe, they are mandated to provide.
Also, their new birds are on KA band, so they don't interfere with the current fleet.
Dish has 118.75 and 119
0.25 of a degree apart.
Well, they are actually at distant ends of the Ku band, so it's easier for the LNB to differentiate between the two birds.
 
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99 and 103 are Ka band. 4 degree spacing in this band. 101 is Ku band.

118.75 is Ku FSS band and 119 is Ku DBS band. They are both circular.
 
Good point on the dish .25º separation.

So the question remains, if Dish and DirecTV can get tight angles, why it FTA limited to 4º/5º?

Again, I'm sure there is a reasonable explanation. ;)

If I had to wager a guess, I would suspect it has to do with the higher power levels for DBS.

EDIT: I expected this to be post #3, but too slow! I see good info in #3 and #4. Thanks! :)
 
Well, the Direct Broadcast Satellite is really 9º spacing.
So when that wasn't good enough, Dish and DirecTV did what is documented above, to cram more into the one little sky we've got. :)
Using different frequencies in one band, using circular vs linear polarization, and using a whole new Ka band, all to avoid interference, allow more channels, etc.

Small (18..22") dishes in Ku band also don't aim that tightly.
So, installs are easier.
The lower power and closer spacing of the typical FTA birds, mandates the bigger dish.
That dish gets the weak signals, and lets you see birds closer together.
But, they're also harder to aim.
 
So the 4º separation for reception:

How much is due to physical limitations of the LNBs (ie physical size)? The GEOSATpro bullet LNBs are pretty small and can get down to 4º.

How much is due to RF issues? Staggering the Ka and Ku signals and LNBs makes sense as described by JohnH. This would suggest that a staggered Ku/Cband approach would work. Something like 97Ku/99C/101Ku or similar.

I ask because I have read many posts here - including those about the T90 where a couple of dishes can be used to fill in the gaps and achieve an overall 2º separation for several satellites. I've gotten a lot of good info from several people (Mike Kohl and Iceberg come to mind) about getting as many sats as possible on as few dishes as possible. For another 6 years or so I belong to the government and will be limited to one dish of the FTA variety until I settle down in one area. I am interested in getting the most out of a stationary dish.

Thanks to all for the informative responses!
 
Iceberg and others have managed 2º on the T-90, but it's using creative techniques.
Some early attempts consisted of grinding down the cases of some LNBs to get them closer together.
See the archives for how that worked out.

More recently, some narrow-horned, band-stacked LNBs were instrumental in getting what I think was reported as reliable 2º spacing...
Read the threads for better info.

As for Ku and C band on the same bird/lnb/dish, that works just fine.
The frequencies are quite far apart, so there is no interference.
Otherwise, we wouldn't have dual-band satellites, and dual-band LNBs. :)
The problems of crowding "97Ku/99C/101Ku" would be strictly mechanical.
But if that was your goal, I wouldn't consider putting my Ku LNBs on a BUD.
Put 'em on a little dish.
 
Thanks Anole!

I have read the threads you mentioned (that was a SuperDish LNB, wasn't it?).

Good to know on the mechanical - that's what I was hoping!
 
Why 2degree spacing?

Here's a link to the FCC freq asked questions:
International Bureau >> Frequently Asked Questions
FAQ #6 is your answer.
The short answer is--so satellite operators can cram more satellites in space over the US!! When C=band was king, there were fewer sats spaced further apart, interference wasn't as big a problem. More services wanted satellite-delivered content=more birds
=more regulation!
 
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