These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

On 18/02/2015 11:10, Windmill wrote:
These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?



The 36v motor that I had used 6 clicks to the degree, so you could move
it in 10 minute increments. I can't give you the same figure for the
more common Diseqc motor, but I would think it would be similar.

With (many) Linux receivers you can use a motor in conjunction with
fixed LNBs. (Two dishes attached to a single LNB port on the receiver.)
The motorised dish only moves if you selection a channel which is not
available from one of the fixed dish LNBs.


--
Michael Chare

Michael Chare writes:

On 18/02/2015 11:10, Windmill wrote:
These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?



The 36v motor that I had used 6 clicks to the degree, so you could move
it in 10 minute increments. I can't give you the same figure for the
more common Diseqc motor, but I would think it would be similar.

With (many) Linux receivers you can use a motor in conjunction with
fixed LNBs. (Two dishes attached to a single LNB port on the receiver.)
The motorised dish only moves if you selection a channel which is not
available from one of the fixed dish LNBs.

I've got one receiver which can only 'see' either a motor plus LNB, or
a tree of fixed LNBs, and another which can select either as you say.

I only have one dish, and nowhere to put a second, so I want to mount
several LNBs (offset appropriately with home-brew mountings) on that
one dish. There are several satellites whose position differs by
similar amounts, so there's a possibility of moving the dish but still
picking up more than one satellite at the same time (via different LNBs
of course).

But it isn't clear to me whether the offset LNBs would be pointing
somewhere which was still in the ring of satellites, with correct
azimuth and correct elevation, after the dish motor has moved the dish.


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

On Saturday, February 21, 2015 at 5:37:49 PM UTC, Windmill wrote:
Michael Chare writes:

On 18/02/2015 11:10, Windmill wrote:
These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?



The 36v motor that I had used 6 clicks to the degree, so you could move
it in 10 minute increments. I can't give you the same figure for the
more common Diseqc motor, but I would think it would be similar.

With (many) Linux receivers you can use a motor in conjunction with
fixed LNBs. (Two dishes attached to a single LNB port on the receiver.)
The motorised dish only moves if you selection a channel which is not
available from one of the fixed dish LNBs.

I've got one receiver which can only 'see' either a motor plus LNB, or
a tree of fixed LNBs, and another which can select either as you say.

I only have one dish, and nowhere to put a second, so I want to mount
several LNBs (offset appropriately with home-brew mountings) on that
one dish. There are several satellites whose position differs by
similar amounts, so there's a possibility of moving the dish but still
picking up more than one satellite at the same time (via different LNBs
of course).

But it isn't clear to me whether the offset LNBs would be pointing
somewhere which was still in the ring of satellites, with correct
azimuth and correct elevation, after the dish motor has moved the dish.

Have you tried Satcure
http://www.satcure.co.uk/tech/page9.htm

if your dish was motorized it would rotate on the N-S axis exactly, but a SKY fixed type won't. However a straight line run of LNBs a few inches apart should scan the sky at a constant elevation (roughly) on a SKY dish. Which is an offset parabola.

rusty

therustyone writes:

On Saturday, February 21, 2015 at 5:37:49 PM UTC, Windmill wrote:
Michael Chare writes:

On 18/02/2015 11:10, Windmill wrote:
These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?



The 36v motor that I had used 6 clicks to the degree, so you could move
it in 10 minute increments. I can't give you the same figure for the
more common Diseqc motor, but I would think it would be similar.

With (many) Linux receivers you can use a motor in conjunction with
fixed LNBs. (Two dishes attached to a single LNB port on the receiver.)
The motorised dish only moves if you selection a channel which is not
available from one of the fixed dish LNBs.

I've got one receiver which can only 'see' either a motor plus LNB, or
a tree of fixed LNBs, and another which can select either as you say.

I only have one dish, and nowhere to put a second, so I want to mount
several LNBs (offset appropriately with home-brew mountings) on that
one dish. There are several satellites whose position differs by
similar amounts, so there's a possibility of moving the dish but still
picking up more than one satellite at the same time (via different LNBs
of course).

But it isn't clear to me whether the offset LNBs would be pointing
somewhere which was still in the ring of satellites, with correct
azimuth and correct elevation, after the dish motor has moved the dish.

Have you tried Satcure
http://www.satcure.co.uk/tech/page9.htm

Didn't see anything relevant there, and that it seems they don't
want to give advice about things they didn't sell to you.

if your dish was motorized it would rotate on the N-S axis exactly,

Wouldn't that mean that unless you were on the equator or at one of the
poles, the required elevation would change when the dish moved?

but a SKY fixed type won't. However a straight line run of LNBs a few
inches apart should scan the sky at a constant elevation (roughly) on a
SKY dish. Which is an offset parabola.

Don't see that it matters whether the dish is Sky or not.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

On 21/02/2015 17:18, Windmill wrote:
Michael Chare writes:

On 18/02/2015 11:10, Windmill wrote:
These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?



The 36v motor that I had used 6 clicks to the degree, so you could move
it in 10 minute increments. I can't give you the same figure for the
more common Diseqc motor, but I would think it would be similar.

With (many) Linux receivers you can use a motor in conjunction with
fixed LNBs. (Two dishes attached to a single LNB port on the receiver.)
The motorised dish only moves if you selection a channel which is not
available from one of the fixed dish LNBs.

I've got one receiver which can only 'see' either a motor plus LNB, or
a tree of fixed LNBs, and another which can select either as you say.

I only have one dish, and nowhere to put a second, so I want to mount
several LNBs (offset appropriately with home-brew mountings) on that
one dish. There are several satellites whose position differs by
similar amounts, so there's a possibility of moving the dish but still
picking up more than one satellite at the same time (via different LNBs
of course).

But it isn't clear to me whether the offset LNBs would be pointing
somewhere which was still in the ring of satellites, with correct
azimuth and correct elevation, after the dish motor has moved the dish.



I am not sure that your receiver would accept a configuration where it
could either move the dish or use an offset LNB.

You could try posting in the digitalspy.co.uk satellite/Technical forum.

http://forums.digitalspy.co.uk/forumdisplay.php?f=11


--
Michael Chare

On 21/02/2015 18:06, Michael Chare wrote:
On 21/02/2015 17:18, Windmill wrote:
Michael Chare writes:

On 18/02/2015 11:10, Windmill wrote:
These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by
comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?



The 36v motor that I had used 6 clicks to the degree, so you could move
it in 10 minute increments. I can't give you the same figure for the
more common Diseqc motor, but I would think it would be similar.

With (many) Linux receivers you can use a motor in conjunction with
fixed LNBs. (Two dishes attached to a single LNB port on the receiver.)
The motorised dish only moves if you selection a channel which is not
available from one of the fixed dish LNBs.

I've got one receiver which can only 'see' either a motor plus LNB, or
a tree of fixed LNBs, and another which can select either as you say.

I only have one dish, and nowhere to put a second, so I want to mount
several LNBs (offset appropriately with home-brew mountings) on that
one dish. There are several satellites whose position differs by
similar amounts, so there's a possibility of moving the dish but still
picking up more than one satellite at the same time (via different LNBs
of course).

But it isn't clear to me whether the offset LNBs would be pointing
somewhere which was still in the ring of satellites, with correct
azimuth and correct elevation, after the dish motor has moved the dish.



I am not sure that your receiver would accept a configuration where it
could either move the dish or use an offset LNB.

You could try posting in the digitalspy.co.uk satellite/Technical forum.

http://forums.digitalspy.co.uk/forumdisplay.php?f=11


A domestic Satellite dish might just be able to receive from satellites
within a 2 degree arc, but really to get good reception the satellites
need to be within a 1 degree arc. Generally, larger dishes need to be
more accurately aligned as they can receive from a smaller arc.

Maybe the OP should indicate what atellites he wants to receive from.


--
Michael Chare

Michael Chare mUNDERSCOREnews@chareDOTorgDOTuk writes:

On 21/02/2015 18:06, Michael Chare wrote:
On 21/02/2015 17:18, Windmill wrote:
Michael Chare writes:

On 18/02/2015 11:10, Windmill wrote:
These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by
comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?



The 36v motor that I had used 6 clicks to the degree, so you could move
it in 10 minute increments. I can't give you the same figure for the
more common Diseqc motor, but I would think it would be similar.

With (many) Linux receivers you can use a motor in conjunction with
fixed LNBs. (Two dishes attached to a single LNB port on the receiver.)
The motorised dish only moves if you selection a channel which is not
available from one of the fixed dish LNBs.

I've got one receiver which can only 'see' either a motor plus LNB, or
a tree of fixed LNBs, and another which can select either as you say.

I only have one dish, and nowhere to put a second, so I want to mount
several LNBs (offset appropriately with home-brew mountings) on that
one dish. There are several satellites whose position differs by
similar amounts, so there's a possibility of moving the dish but still
picking up more than one satellite at the same time (via different LNBs
of course).

But it isn't clear to me whether the offset LNBs would be pointing
somewhere which was still in the ring of satellites, with correct
azimuth and correct elevation, after the dish motor has moved the dish.



I am not sure that your receiver would accept a configuration where it
could either move the dish or use an offset LNB.

You could try posting in the digitalspy.co.uk satellite/Technical forum.

http://forums.digitalspy.co.uk/forumdisplay.php?f=11


A domestic Satellite dish might just be able to receive from satellites
within a 2 degree arc, but really to get good reception the satellites
need to be within a 1 degree arc. Generally, larger dishes need to be
more accurately aligned as they can receive from a smaller arc.

Maybe the OP should indicate what atellites he wants to receive from.

Any satellite above the horizon, basically, using the dish motor.

What I'm wondering about (and having trouble putting into words) is
this:

Suppose the dish is pointed in such a way as to pick up Astra 2A and
(via another LNB offset on an arm on the dish) Hotbird.
So far, so good: things like that do work for me, though there are
some issues with receiver control capabilities, and it might be better
to connect the second LNB to a different receiver.

If the dish motor then moves the dish to point to a satellite at say 5
degrees, would the offset LNB still be pointing somewhere in the ring
of satellites (I suppose it might perhaps get Astra 1), or would
it be pointing above or below the ring where the satellites lie?

If you look at the extreme case of a dish which you've moved to point
near the horizon, everything is at weird angles, including the offset
LNB on its arm, and I'm not sure if the latter would still be pointing
somewhere in the ring of satellites.

I don't think there's a problem if you are at the poles or on the
equator, but everywhere else the azimuth has to change as the dish is
moved, and I can't work out if the offset LNB would still be pointing
in the appropriate direction.

Of course I should have tested this while I had the dish behind a
window in the front room, where it was easily accessible.


--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

Michael Chare writes:

On 21/02/2015 17:18, Windmill wrote:
Michael Chare writes:

On 18/02/2015 11:10, Windmill wrote:
These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?



The 36v motor that I had used 6 clicks to the degree, so you could move
it in 10 minute increments. I can't give you the same figure for the
more common Diseqc motor, but I would think it would be similar.

With (many) Linux receivers you can use a motor in conjunction with
fixed LNBs. (Two dishes attached to a single LNB port on the receiver.)
The motorised dish only moves if you selection a channel which is not
available from one of the fixed dish LNBs.

I've got one receiver which can only 'see' either a motor plus LNB, or
a tree of fixed LNBs, and another which can select either as you say.

I only have one dish, and nowhere to put a second, so I want to mount
several LNBs (offset appropriately with home-brew mountings) on that
one dish. There are several satellites whose position differs by
similar amounts, so there's a possibility of moving the dish but still
picking up more than one satellite at the same time (via different LNBs
of course).

But it isn't clear to me whether the offset LNBs would be pointing
somewhere which was still in the ring of satellites, with correct
azimuth and correct elevation, after the dish motor has moved the dish.



I am not sure that your receiver would accept a configuration where it
could either move the dish or use an offset LNB.

It can do that sort of thing; I've tried a simpler configuration where
you can either select the motorised dish, or say there's no motor and
then select via a DisEqC switch a different dish. But I don't think it
can do it automatically, based on channel selection.

The other receiver which I haven't really used yet seems to have that
kind of capability. BICBW.

You could try posting in the digitalspy.co.uk satellite/Technical forum.

http://forums.digitalspy.co.uk/forumdisplay.php?f=11

Thanks; I'll give that a try.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost

Michael Chare writes:

On 18/02/2015 11:10, Windmill wrote:
These dish motors can't be the sort of simple polar mount which works
for small telescopes, because the satellites are too near (by comparison with
astronomical objects) so I think there would be considerable errors in
direction either for satellites near the horizon or for those highest
in the sky (or for both).

My 3D visualisation skills have never been too great, so I don't know
if the oddly-angled dish mounting tube somehow compensates for this.
Or if it does, how well it does.

The reason I want to know is that if I add some home-brew LNBs offset
'x' degrees from the axis of the dish so as to pick up several
satellites without moving the dish, there could be a problem when the
dish is in fact moved.

The axis of the dish maybe still points accurately at some location in
the circle of satellites (if that angled tube somehow compensates for
the different distances to satellites low and high in the sky), but the
offset LNBs might not still be 'x' degrees behind or ahead or might be
pointing above or below that circle of satellites.

As I say, I have trouble visualising this situation. Can anyone help?



The 36v motor that I had used 6 clicks to the degree, so you could move
it in 10 minute increments. I can't give you the same figure for the
more common Diseqc motor, but I would think it would be similar.

With (many) Linux receivers you can use a motor in conjunction with
fixed LNBs. (Two dishes attached to a single LNB port on the receiver.)
The motorised dish only moves if you selection a channel which is not
available from one of the fixed dish LNBs.

I have one receiver which allows either DisEqC1.3 or 1.2 but not both
(the 1.2 menu items disappear when USALS is selected), and another
which seems to allow selection of either one of several top-level LNBs
in a tree structure, or of a motorised LNB at a lower level, but I
haven't verified that yet.

However what I really want to know is whether a motorised dish is
driven in such a way that when the dish is moved, multiple offset LNBs
will still track, in azimuth and elevation and polarisation, all points
in the ring of synchronous satellites.

IYSWIM.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost