Bargain Second-Hand Big Dishes For Sale

[Channel Hopper]

He needs to increase the range of the declination angle to match the offset of the dish.

All that is required is a 'V' or wedge that has the same angle as the Channel Master reflector offset. The Superjack 1224 has a similar design option to allow operation with non prime focus dishes.

The front end of the IRTE polar mount with four bolt holes is more than adequate to hold the weight of the dish and ironmongery securely.

 

[moonbase]

He needs to increase the range of the declination angle to match the offset of the dish.

Assuming a suitable frame can be fabricated of correct dimensions to accomodate the 1.8m CM dish, the increased declination could be introduced using some brackets similar to those pictured below.
These brackets could be attached to the top horizontal strut of the interface frame to provide additional declination.

Additionally, four small 90 degree brackets with a hole drilled in each face would be needed to facilitate use of the declination brackets. These 4 x 90 degree brackets could be easily made by cutting them from a lenth of angle iron.

I am not advocating modification of an IRTE polar mount as a "go for it" solution for the 1.8m channel master dish. The IRTE polar mount is unsuitable in my view and there are better options available, albeit more expensive.
However, it is possible to get a 1.8m channel master dish mounted on an IRTE polar mount but it does need some basic tools such as a hacksaw and a decent drill plus the aptitude to go for it.

.

 

[moonbase]

This would not help in this situation as you need to have an extended declination adjustment of 108mm.

Just a quick brain fart, does the top length of the IRTE polar mount have enough length to it to allow cutting/extending the declination adjustment slider hole?
I no longer have the IRTE polar mount to measure.

 

[Captain Jack]

Channel Master/Laminas 1.8m project

Very lucky you thought of adding the chain .

satellites.co.uk

This is how I adapted a Precision PM designed for prime focus to 1.8m Channel Master.

 

[OverwatchX]

Just a quick brain fart, does the top length of the IRTE polar mount have enough length to it to allow cutting/extending the declination adjustment slider hole?
I no longer have the IRTE polar mount to measure.

Unfortunately no, I created a template for him to use to extend it easily though from a bit of steel 8-10mm thick, without the need for a wedge.

 

[OverwatchX]

Channel Master/Laminas 1.8m project

Very lucky you thought of adding the chain .

satellites.co.uk

This is how I adapted a Precision PM designed for prime focus to 1.8m Channel Master.

Thats a nice modification, some real nice work there.

This is how i did my 1.2

 

[moonbase]

Channel Master/Laminas 1.8m project

Very lucky you thought of adding the chain .

satellites.co.uk

This is how I adapted a Precision PM designed for prime focus to 1.8m Channel Master.

I remember that mod CJ, it was very nice.
Fortunately, you had a top class mount in the Precision triangular frame polar mount to start the job with.

 

[moonbase]

Unfortunately no, I created a template for him to use to extend it easily though from a bit of steel 8-10mm thick, without the need for a wedge.

Nice simple solution.

 

[John]

.. Iv'e used 'Alternator brackets' in the past for similar ideas - various sizes and shapes.

Alternator Mounting Brackets Car Van Truck Boat Multiple Sizes Adjustable | eBay

A selection of Alternator Brackets for your Car, Van, Truck or Boat. Alternator Bracket. Bright Zinc Plated.

www.ebay.co.uk

 

[moonbase]

.. Iv'e used 'Alternator brackets' in the past for similar ideas - various sizes and shapes.

Alternator Mounting Brackets Car Van Truck Boat Multiple Sizes Adjustable | eBay

A selection of Alternator Brackets for your Car, Van, Truck or Boat. Alternator Bracket. Bright Zinc Plated.

www.ebay.co.uk

They look like they were designed for the job of extending declination.

 

[Channel Hopper]

Unfortunately no, I created a template for him to use to extend it easily though from a bit of steel 8-10mm thick, without the need for a wedge.

From memory, (I'm going on the roof to check important dimensions as it is raining, again) the lower part of the bearing 'C' cage can be drilled with a hole further forward, with the bearing bolt inserted accordingly (perhaps with some metalwork shaved from the rectangular base corners to allow full arc movement), an offset closer to that of the Channel Master design should be possible.

No guarantee it is going to be fully compatible (and a 'V' wedge may still be required), but the reflector mass will be closer to the bearings and the quality of the IRTE polarmount will keep everything shipshape for near perpetuity.

 

[moonbase]

If the member asking about the polar mount for a CM 1.8m dish has potential options for another dish/mount I think they are better off going in that direction. From personal experience of modding an IRTE polar mount to accept another make of dish I would not repeat the procedure due to the moderate quality of the bearings and the lack of sensitivity on the actuator travel due to the proximity of the actuator end fixing point to the rotational axis.

Sure, it can be done, however out of choice I would swerve it and look for alternative options.

 

[moonbase]

2.4m Prime Focus dish on eBay, £40 starting bid or buy it now for £80.

2.4m 8ft Prime Focus Satellite Dish (C-Band) | eBay

<p dir="ltr">For sale is a 240cm prime focus satellite dish for C-Band reception. Comes with the reflector itself, feedarms and the required bolts and nuts to put it together. You will need your own stand.I have two sets of feedarms, the original ones are included. If you also want the aluminium...

www.ebay.co.uk

Sold £46.89p, a bargain for someone looking for a C-Band dish, was it bought by a forum member, hands up !

Nicknamed "The Tin Dish" on the forum, the 2.4m Fortec Star performed reasonably well in C-Band based on observations from a few forum members, "aceb" and "s-band" spring to mind.

 

[butchyboy]

guys where could i possibly get the whole polarmount 1.8m offset channel master dimensions where i could get one made up,any ideas or help please.

 

[Channel Hopper]

From personal experience of modding an IRTE polar mount to accept another make of dish I would not repeat the procedure due to the moderate quality of the bearings and the lack of sensitivity on the actuator travel due to the proximity of the actuator end fixing point to the rotational axis.

The IRTE polar mount lends itself very easily to actuator modification, usually little more than drilling one or two holes with a minimum of calculation.

A child could do it.

 

[moonbase]

The IRTE polar mount lends itself very easily to actuator modification, usually little more than drilling one or two holes with a minimum of calculation.

A child could do it.

It is not just a matter of drilling holes, the actuator end fixing bar needs to be replaced with a longer version.
In addition, there is still the issue of the moderate quality bearings on the IRTE polar mount.

Having modified one of these IRTE mounts for use with another make of dish I would not do it again.
In my personal opinion the IRTE polar mount fulfils a role in the market, it is at the bottom end.

 

[OverwatchX]

If the member asking about the polar mount for a CM 1.8m dish has potential options for another dish/mount I think they are better off going in that direction. From personal experience of modding an IRTE polar mount to accept another make of dish I would not repeat the procedure due to the moderate quality of the bearings and the lack of sensitivity on the actuator travel due to the proximity of the actuator end fixing point to the rotational axis.

Sure, it can be done, however out of choice I would swerve it and look for alternative options.

To increase sensitivity of the actuator he can extend the right angle bar. Only issue with this is more sensitivity = less travel. In my experience, the sensitivity isnt an issue, but the strain on the jack is. Less sensitivity = more strain on the actuator threads and motor.

 

[OverwatchX]

Sold £46.89p, a bargain for someone looking for a C-Band dish, was it bought by a forum member, hands up !

Nicknamed "The Tin Dish" on the forum, the 2.4m Fortec Star performed reasonably well in C-Band based on observations from a few forum members, "aceb" and "s-band" spring to mind.

I was going to buy this and was seconds away from clicking to bid, when i realised its too far away to collect with lockdown rules. With my luck I would get fined £250 for a £40 dish!

 

[Channel Hopper]

To increase sensitivity of the actuator he can extend the right angle bar. Only issue with this is more sensitivity = less travel. In my experience, the sensitivity isnt an issue, but the strain on the jack is. Less sensitivity = more strain on the actuator threads and motor.

The bar could be extended, but the design allows the existing item to be angled backwards with one additional hole drilled moving the actuator pivot further from the polar bearings.

https://satellites.co.uk/forums/attachments/60-west-ish-jpg.65309/

The number of pulses per degree of rotation will increase slightly, lowering of strain on the actuator, as long as the length of the actuator is greater than the total travel east /west then it's win-win.

 

[moonbase]

I was going to buy this and was seconds away from clicking to bid, when i realised its too far away to collect with lockdown rules. With my luck I would get fined £250 for a £40 dish!

Shame, it would have been nice to see it feature in an install topic on the forum, particularly on C-Band.

I suppose you could ask the seller to contact you if the sale falls through with the winning bidder, sometimes winning bidders get buyers remorse. If the sale does fall through you could ask the seller if he will hold it for you until lockdown rules ease to allow travel?