Are steering mechanisms sufficiently stable, and sufficiently precise,
to allow use of the same dish with both TV and broadband?
(Obviously two LNBs slightly offset from each other might be required,
depending on frequency etc.)

Allegedly, great precision is needed for broadband (though I don't see
why; presumably any reasonably-sized dish would have a fairly large
beam width).

Do steering mechanisms use stepping motors, so that there is a minimum
possible angular change, or are some/all capable of any desired degree
of movement?


--
Windmill, Use t m i l l
@ O n e t e l
. c o m

Windmill wrote:
Are steering mechanisms sufficiently stable, and sufficiently precise,
to allow use of the same dish with both TV and broadband?
(Obviously two LNBs slightly offset from each other might be required,
depending on frequency etc.)

Won't you have an issue that the signals come from two different satellites,
at two different angles? Both geostationary, but one at XX degrees W and
another at YY degrees E, or whatever. Or are they on the same satellite?

Do steering mechanisms use stepping motors, so that there is a minimum
possible angular change, or are some/all capable of any desired degree
of movement?

If there's servo control then high resolution should be possible
(nanodegrees or something), though whether you can buy such a thing cheap
enough and designed for satellite positioning I don't know.

Theo

Windmill wrote:
Are steering mechanisms sufficiently stable, and sufficiently precise,
to allow use of the same dish with both TV and broadband?
(Obviously two LNBs slightly offset from each other might be required,
depending on frequency etc.)

Allegedly, great precision is needed for broadband (though I don't see
why; presumably any reasonably-sized dish would have a fairly large
beam width).


Fundamental misconception of optics. (of which RF is a special long
wavelength case) The larger the dish, the smaller the beam width, generally.

Do steering mechanisms use stepping motors, so that there is a minimum
possible angular change, or are some/all capable of any desired degree
of movement?

Pass.

Theo Markettos wrote:
Windmill wrote:
Are steering mechanisms sufficiently stable, and sufficiently precise,
to allow use of the same dish with both TV and broadband?
(Obviously two LNBs slightly offset from each other might be required,
depending on frequency etc.)

Won't you have an issue that the signals come from two different satellites,
at two different angles? Both geostationary, but one at XX degrees W and
another at YY degrees E, or whatever. Or are they on the same satellite?

Do steering mechanisms use stepping motors, so that there is a minimum
possible angular change, or are some/all capable of any desired degree
of movement?

If there's servo control then high resolution should be possible
(nanodegrees or something), though whether you can buy such a thing cheap
enough and designed for satellite positioning I don't know.

Theo
Certainly can. My BIL in Germany had such years ago in his back garden.

Could pick up one of three or four different satellites. Controlled
(when it worked) by a 'remote' similar to any other TV remote.


Time and the weather reduced its reliability ISTR.

On May 18, 10:21*am, (Windmill)
wrote:
Are steering mechanisms sufficiently stable, and sufficiently precise,
to allow use of the same dish with both TV and broadband?
(Obviously two LNBs slightly offset from each other might be required,
depending on frequency etc.)

Allegedly, great precision is needed for broadband (though I don't see
why; presumably any reasonably-sized dish would have a fairly large
beam width).


the bigger the dish the smaller the beam-width of course...

Robert

On 18/05/2011 10:21, Windmill wrote:
Are steering mechanisms sufficiently stable, and sufficiently precise,
to allow use of the same dish with both TV and broadband?
(Obviously two LNBs slightly offset from each other might be required,
depending on frequency etc.)

Allegedly, great precision is needed for broadband (though I don't see
why; presumably any reasonably-sized dish would have a fairly large
beam width).

Do steering mechanisms use stepping motors, so that there is a minimum
possible angular change, or are some/all capable of any desired degree
of movement?



Normally you either have a steerable dish with one LNB or a fixed dish
with maybe multiple offset LNBs.

Large dishes collect more signal, but have to be more accurately aligned.

IME the biggest problem is find the satellite in the first place. Making
small adjustments to maximise the signal quality is not difficult.

My 90cm dish uses a 36v motor. When it moves it opens and closes a
switch 6 times per degree. When I change satellites the receiver normall
sets the dish to exactly the right position. Normally I would get enough
signal if the the disk is a couple 'clicks' out. I used to move the dish
from Astra 2 at 28.2 to Euobird at 28.5. I now don't bother.

Most European domestic steerable dishes use DiSEqc 1.2 motors. Which I
think do allow even more precise setting.


--
Michael Chare

"Windmill" wrote in message ...
Are steering mechanisms sufficiently stable, and sufficiently precise,
to allow use of the same dish with both TV and broadband?
(Obviously two LNBs slightly offset from each other might be required,
depending on frequency etc.)

Allegedly, great precision is needed for broadband (though I don't see
why; presumably any reasonably-sized dish would have a fairly large
beam width).

Do steering mechanisms use stepping motors, so that there is a minimum
possible angular change, or are some/all capable of any desired degree
of movement?


--
Windmill, Use t m i l l
@ O n e t e l
. c o m

Can you give more information?
Which satellite broadband system, provided on which satellite?
is it downlink only or up/down?

Which TV satellite? A different one presumably

What if you want to watch TV and use broadband simultaneously?

Why does it need to be done with a common dish?

--
Graham.

%Profound_observation%

On May 18, 1:23*pm, Theo Markettos
wrote:
Windmill wrote:
Are steering mechanisms sufficiently stable, and sufficiently precise,
to allow use of the same dish with both TV and broadband?
(Obviously two LNBs slightly offset from each other might be required,
depending on frequency etc.)

Won't you have an issue that the signals come from two different satellites,
at two different angles? *Both geostationary, but one at XX degrees W and
another at YY degrees E, or whatever. *Or are they on the same satellite?

Do steering mechanisms use stepping motors, so that there is a minimum
possible angular change, or are some/all capable of any desired degree
of movement?

If there's servo control then high resolution should be possible
(nanodegrees or something), though whether you can buy such a thing cheap
enough and designed for satellite positioning I don't know.

Theo

Anybody want to buy a 6 foot dish and ground mount - collection only
in East Yorkshire?
Needs new LNB