DIY Horizon to Horizon Polar Mount

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blademedia

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blademedia,

You put in a lot of work and time to build this chain driven polar mount and it looks to be very high quality. Have you plans for it now you have installed the 2.4m DH antenna? I hope the chain drive mount gets put into service as it is a top class piece of fabrication and whoever uses it will get many years use out of it.

Rgds
Thanks moonbase,

I've just bought a 2.7 dish :-dohI was going to sell 2.4 channel master with chain driven mount, new plan is sell 2.4 with fixed AZ/EL use chain driven mount on 2.7,

Unsure when this will happen, maybe next year.
 
M

moonbase

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Thanks moonbase,
I've just bought a 2.7 dish :-dohI was going to sell 2.4 channel master with chain driven mount, new plan is sell 2.4 with fixed AZ/EL use chain driven mount on 2.7,
Unsure when this will happen, maybe next year.

blademedia,

A 2.7m dish, what make, is it a prime focus or offset focus? Any pictures please?
You like these big antenna, what will the neighbours think when this one goes up, will the man from the council have to come back?

Amazing stuff, motorised 2.4m and chain driven motorised 2.7m, it gets better every day. :)

Rgds
 
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Thanks moonbase,

I've just bought a 2.7 dish :-dohI was going to sell 2.4 channel master with chain driven mount, new plan is sell 2.4 with fixed AZ/EL use chain driven mount on 2.7,

Unsure when this will happen, maybe next year.



:eek::D:eek::D....Yeee-Haaaa- you kept that quiet. +1 for more info / pics
 
B

blademedia

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blademedia,

A 2.7m dish, what make, is it a prime focus or offset focus? Any pictures please?
You like these big antenna, what will the neighbours think when this one goes up, will the man from the council have to come back?

Amazing stuff, motorised 2.4m and chain driven motorised 2.7m, it gets better every day. :)

Rgds
Hi moonbase, the dish is a prime focus made/bought from Echosphere in the USA, I don't have the dish yet it will be shipped to me next month, I will post pictures when it arrives.
 
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moonbase

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Hi moonbase, the dish is a prime focus made/bought from Echosphere in the USA, I don't have the dish yet it will be shipped to me next month, I will post pictures when it arrives.
blademedia,

Another prime focus, awesome, is it a one piece dish? They do look good and at 2.7 metres it will look extra good.
Cant wait for the installation topic to begin when you start it.

Was it more cost effective, or was there any other reason why you got it from Echosphere in the USA and imported it instead of getting a 2.8m from Elite in the UK.?


Rgds
 
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Hi moonbase, its a quality peteled dish, the dish is not new its a used dish, both DH and 2,7 wont be up at the same time, I will put the 2.7 up and test it against the 2.4, if its better in C and KU band it will stop up if not it will stop down

With it being a older dish it might only perform well in C band, I have no specifications for it
 
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That's a heck of a gamble. How much did it cost and what's the carriage going to sting you for?
 
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That's a heck of a gamble. How much did it cost and what's the carriage going to sting you for?
£400 all in with two nearly new thomson Saginaw, its a friend from Italy who's making the move to UK. I only have to transport it from his house to mine when it arrives.
 
Captain Jack

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Has Italy done something to offend you and your friends? Or perhaps you all want out of EU? ;)
 
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moonbase

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£400 all in with two nearly new thomson Saginaw, its a friend from Italy who's making the move to UK. I only have to transport it from his house to mine when it arrives.

You have a good eye for a bargain and a good quality dish.
I do not know the price of a new Thompson Saginaw actuator, but if they are still in production I can see one of them costing £400 for a 36" model ?

Rgds
 
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You have a good eye for a bargain and a good quality dish.
I do not know the price of a new Thompson Saginaw actuator, but if they are still in production I can see one of them costing £400 for a 36" model ?

Rgds
Unsure what length they are moonbase the motor is the big chunky type, stand polar mount 2.7 dish 2 actuators £400, like you say probably £400 for one new, handy to have as spares quality stuff is hard to find you've got to grab it when you can
 
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moonbase

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@blademedia

I have a couple of questions about your chain drive mount if you can please help me?

1. Do you still have it, if you do would you consider selling it?

Dependent on your answers to point 1, I have two more questions.


2. Can it be adapted for inclined orbit tracking?
3. Can it be adapted to mount a Precision antenna with a 1200 millimetre rear mounting ring (not the usual 600 millimetre mounting ring)?



Rgds
 
B

blademedia

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@blademedia

I have a couple of questions about your chain drive mount if you can please help me?

1. Do you still have it, if you do would you consider selling it?

Dependent on your answers to point 1, I have two more questions.


2. Can it be adapted for inclined orbit tracking?
3. Can it be adapted to mount a Precision antenna with a 1200 millimetre rear mounting ring (not the usual 600 millimetre mounting ring)?



Rgds
Hi moonbase,

Yes I still have the mount but its not for sale at the moment, but I could easily make another to your specification, there easy to make now ive done one the next one will be a breeze,

(2. Can it be adapted for inclined orbit tracking?)

Yes the one ive nearly finished will have inclined orbit tracking I'm copying this design
DIY Horizon to Horizon Polar Mount_1019019 DIY Horizon to Horizon Polar Mount_1019019

(3. Can it be adapted to mount a Precision antenna with a 1200 millimetre rear mounting ring (not the usual 600 millimetre mounting ring)?)
Where talking a big dish, as long as I have accurate measurements its not a problem, I would need to know the size of dish for the pole cap, it sounds like you will need a minimum of 6.5 inch cap,

If your wanting total precision motorized AZ/EL is the way to go the most accurate mount in the world,
DIY Horizon to Horizon Polar Mount_1019019

The above mount can easily be made, the only issue here is cost, the lazy Susan/ slewing ring is around £500 alone.
 
M

moonbase

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If your wanting total precision motorized AZ/EL is the way to go the most accurate mount in the world,
The above mount can easily be made, the only issue here is cost, the lazy Susan/ slewing ring is around £500 alone.


@blademedia

Thank you for your reply.

Yes, I agree about the accuracy of the Az/El mount. the beamwidth of a large antenna is very narrow and to get a polar mount to accurately track an arc between the East/West extreme points might be quite tricky.

The motorised Az/El option with the slewing ring sounds as though it will be the best option for my needs. I have a Research Concepts RC2000C dual axis controller unit that should be able to manage both the slewing ring and the elevation actuator. I need to get the distance distribution of the mounting points on the 1200mm rear mounting ring of the Precision antenna and the recommended pole size. I am not sure if the 4.5" diameter pole I have here is under specified.

If you are in agreement, once I have the measurements and pole cap size I will pass them on to you and we can review the options and cost for you to fabricate the mount? One more question for now if you can help, is the slewing ring or the chain drive mount free from play when it tracks azimuth?


Rgds
 
B

blademedia

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@blademedia

Thank you for your reply.

Yes, I agree about the accuracy of the Az/El mount. the beamwidth of a large antenna is very narrow and to get a polar mount to accurately track an arc between the East/West extreme points might be quite tricky.

The motorised Az/El option with the slewing ring sounds as though it will be the best option for my needs. I have a Research Concepts RC2000C dual axis controller unit that should be able to manage both the slewing ring and the elevation actuator. I need to get the distance distribution of the mounting points on the 1200mm rear mounting ring of the Precision antenna and the recommended pole size. I am not sure if the 4.5" diameter pole I have here is under specified.

If you are in agreement, once I have the measurements and pole cap size I will pass them on to you and we can review the options and cost for you to fabricate the mount? One more question for now if you can help, is the slewing ring or the chain drive mount free from play when it tracks azimuth?


Rgds
Hi moonbase,

Yes the larger dishes have a very tight beam width, it can be time consuming getting it to track correctly in KU band as you will know with the 2.2, C band is more forgiving,

The Research Concepts RC2000C dual axis controller is perfect for the job it also controls the skew which is very important with AZ/EL,

Personally I don't think a 4,5 inch pole is big enough for a precision dish over 2.4 but you can check up on that and I will make the mount as instructed by you,

Once you have the measurement's and we agree on a price I can start fabrication, I will only be able to work on it in my spare time, it could be a few months before completion, since ive retired I have less time on my hands than when I was working full time,

There are various slewing rings on the market, once we are in agreement with fabrication costs I will give you a list to choose from, there the type of item on a mini digger that turns the cab,

Both chain drive and slewing rings are free from play, the gearbox ratio will be up to you I will give you options for this, the higher the gear the slower the dish will move, it can be geared in two ways actuator and gearbox,

Most people try to alter the pulse count that's totally wrong, the way to make a dish more precise is the gearing,

Btw what size dish is it ?, I will look forward to making this mount and seeing your installation progress.
 
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@blademedia

Thank you for your reply.

Yes, I agree about the accuracy of the Az/El mount. the beamwidth of a large antenna is very narrow and to get a polar mount to accurately track an arc between the East/West extreme points might be quite tricky.
From experience, if you are stuck with linear actuators with a degree of backlash, the most accurate positioning is with an Az/El/Az design, which Research Concept software and design does cater for.
 
M

moonbase

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From experience, if you are stuck with linear actuators with a degree of backlash, the most accurate positioning is with an Az/El/Az design, which Research Concept software and design does cater for.

CH,


Moving on from linear actuator based solution, a dual axis slew drive will provide accurate azimuth and elevation control and can be interfaced with a Research Concepts dual axis controller. This looks to be the route to take, however, there are quite a few options for dual axis slew drives so the specifications of the various models need to be considered.

Two points that have high importance in the selection of a dual axis slew drive are the fraction of a degree accuracy of the slewing motors and the wind load capability.


Rgds
 
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From experience, if you are stuck with linear actuators with a degree of backlash, the most accurate positioning is with an Az/El/Az design, which Research Concept software and design does cater for.
With tracking enabled or just stored values?
 
Channel Hopper

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CH,


Moving on from linear actuator based solution, a dual axis slew drive will provide accurate azimuth and elevation control and can be interfaced with a Research Concepts dual axis controller. This looks to be the route to take, however, there are quite a few options for dual axis slew drives so the specifications of the various models need to be considered.

Two points that have high importance in the selection of a dual axis slew drive are the fraction of a degree accuracy of the slewing motors and the wind load capability.


Rgds
What is the highest frequency you wish to receive from this system ?
 
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