Mounting offset dish horizontally on a polar mount?

ozumo

ozumo

te wo tsuite
Staff member
My Satellite Setup
Channel Master 90cm, 1.2m & 1.8m PF
My Location
UK
If I mount an offset Channel Master 1.2m horizontally/at 90 degrees on a polar mount, along with adjusting the declination do I need to rotate the polar mount on the pole, or leave the polar mount where it is and make a bracket put the dish into the correct position?

Both would change the azimuth of the dish face at an amount equal to the offset angle but I can't get my head around if there is any difference between the two options, if one is the correct method or if I've got it completely wrong :confused
 
You have to leave the polarmount on the pole , thats the right way to follow the clarkbelt
 
A polar mount should always be first aligned true South/North at any location, and the same for any motorized dish, (if you using a motor) if no motor is to be used then the dish and mount should be moved and aligned as a unit to what ever satellite your going to fix it on, then the dish can be set to the correct declination for that satellite at your location, the LNB or dish on a fixed installation will also need to be skewed to what ever is needed for that satellite.(if the satellite is off of true South)

What are you trying to do?
 
Terryl said:
What are you trying to do?
Click to expand...
I would suspect trying to lower the profile of the reflector to stop the neighbours discovering the 'monstrocity'.

But yes, the polarmount stays where it is, though the north/south is effectively including the declination of the dish design (+/- about 22 degrees depending on which side you fit the fibreglass)

I think with Channel Master you will need to drill new holes in the polarmount since it wasn't square to start with, but it has been a long time since i fitted one.

Oh, and the cross polarisation once you have skewed the LNB to an optimum point will no longer be 90 degrees.

(It's by far easier to invert the dish by 180)
 
Thanks all :Y

I only have a narrow gap for the dish to 'look' through due to trees and the house, and therefore a very limited arc (33e to 15w). Tests with the dish on an az/el mount (the holes are square) suggest I can increase my eastern arc with a horizontal dish at the expense of the western end, which is preferable.

The neighbours don't mind, it's the morons from further afield who like to whinge on facebook and to the council. The lower profile would however mean the dish can be raised slightly while still maintaining a level of stealth from street level.

Another other option is to raise the pole and mount the dish on a pendulum type setup, with steel angle extending down from the polar mount & the dish mounted at the bottom. The swing extends the arc slightly by moving the dish away from the house and tree as well as raising the dish the further away from due south it gets. I think this kind of setup would be more susceptible to strong winds putting strain the mount and motor though.

Using steel angle to move the dish to the right could also be done. I can't move the pole further to the right due to a manhole.
 
You will not get a better spread of satellites by moving the dish on a fixed post.

Sorry
 
On an az/el mount the dish mounted horizontally (LNB at 9 o'clock from the front) gets better signai on the east end of the arc satellites and worse on the west. The dish face is more shadowed by the west obstacle (tree) and less from the east one (house) as it is 22.5 degrees further around the pole.
 
ozumo said:
On an az/el mount the dish mounted horizontally (LNB at 9 o'clock from the front) gets better signai on the east end of the arc satellites and worse on the west. The dish face is more shadowed by the west obstacle (tree) and less from the east one (house) as it is 22.5 degrees further around the pole.
Click to expand...

Ah! That is probably because the position of the dish's mounting bracket, relative to the height of the dish (nearer to top of dish, or nearer to bottom of dish), causing the whole dish being more left or right to the pole when mounted at 90 degrees!

Now I believe I understand what you mean. You cannot move the pole left or right, but you want to have the dish more left or right relative to the pole, right?
(That is also why you thought about the pendulum setup, relative to the motor axis.)

Well, if you want to have your setup moved to left or right, but not the floor-position of the pole, I think a lot is possible.
First thing I thought of is mounting a parallel pole to your pole, and mounting your polar mount on that.

Greetz,
A33
 
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ozumo said:
On an az/el mount the dish mounted horizontally (LNB at 9 o'clock from the front) gets better signai on the east end of the arc satellites and worse on the west. The dish face is more shadowed by the west obstacle (tree) and less from the east one (house) as it is 22.5 degrees further around the pole.
Click to expand...
Only if there is a large difference between the centre point of the mounting brackets securing the reflector, top to bottom

On a Channel Master dish this is not the case.
 
a33 said:
Ah! That is probably because the position of the dish's mounting bracket, relative to the height of the dish (nearer to top of dish, or nearer to bottom of dish), causing the whole dish being more left or right to the pole when mounted at 90 degrees!
Click to expand...
Channel Master dish mount is in the middle and because the holes are square it is simple to rotate the dish in right angles. There is an extra 10cm 'width' when mounted at 90 degrees, the need to raise the elevation on the az/el will also account for some of the signal gain as it it less shadowed by the fence.

Now I believe I understand what you mean. You cannot move the pole left or right, but you want to have the dish more left or right relative to the pole, right?
(That is also why you thought about the pendulum setup, relative to the motor axis.)
Click to expand...
Yes this is the aim. I wish to move the receivable arc further to the east. I don't need anything past 5 west on this dish, however more arc is always nice.

A pendulum setup like this would be interesting to try:

Polar mount stabilisation

Hi! I have mentioned this already couple of times but just saying sometimes is not enough. So, I decided to show how practically is possible to eliminate Polar Mount (PM) issues when it is hard for actuator to bring antenna from very edgy position. Of course everybody has heard about using of...
www.satellites.co.uk www.satellites.co.uk

Well, if you want to have your setup moved to left or right, but not the floor-position of the pole, I think a lot is possible.
First thing I thought of is mounting a parallel pole to your pole, and mounting your polar mount on that.

Greetz,
A33
Click to expand...
Moving the dish face across the front of the polar mount is the easiest thing to try first I think, about half a dish width. I already have 50mm x 50mm x 5mm thickness steel angle. Not needing past 5w should mean the lowering of the dish when moving to the west side caused by the extensions should be acceptable :)
 
Channel Hopper said:
Only if there is a large difference between the centre point of the mounting brackets securing the reflector, top to bottom

On a Channel Master dish this is not the case.
Click to expand...

When the dish is mounted on the az/el at 90 degrees so the LNB is at 3 o'clock from behind, for the same satellite the signal received by the dish is from further to the right than when the dish is in it's normal position. It's not a huge difference but there is one.
 
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ozumo said:
A pendulum setup like this would be interesting to try:
Click to expand...
Yes indeed. It would increase you arc, not only move it sideways. :-) (But would it be enough?)
BTW I believe there is a more recent build by @RimaNTSS of this 'hanging design', but I've not tried to find it.

Just mounting the dish left or right of the axis, and a counterweight at the other side, could be enough? (edit: as you already described)
No need for a 90 degree turn, then.
But I don't know what possibilities you have at the back side of the CM dish.

Greetz,
A33
 
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a33 said:
Yes indeed. It would increase you arc, not only move it sideways. :-) (But would it be enough?)
BTW I believe there is a more recent build by @RimaNTSS of this 'hanging design', but I've not tried to find it.
Click to expand...

This one?

Another Polar-mount for 1,2m Channel Master

Hi all! I think I've started new project, which is logical continuation of this thread. About 10 or so years ago I've seen the developing of this idea on another forum. But at that time I was not ready, and also not interested to follow it. Basic idea behind this design that continuation of axis...
www.satellites.co.uk www.satellites.co.uk

Just mounting the dish left or right of the axis, and a counterweight at the other side, could be enough? No need for a 90 degree turn, then.
But I don't know what possibilities you have at the back side of the CM dish.

Greetz,
A33
Click to expand...

Yes this is what I meant when talking about moving the dish to the right of the polar mount face. It is simple to do on a Channel master with lengths of L shape steel angle.

I did think of a counter weight, a second Channel Master 1.2m, wind loading might be a problem but would be good for comparing LNBs at the centre of the arc :lol:
 
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