How much arc would I gain (approx) ?

[Huevos]

The way I see it is you don't need a longer actuator. If you look at my picture, if you drill the hole where the red circle is you will have lots more rotation to the east before the actuator runs into the mount. And if that's not enough, make up a plate and attach the actuator where the green circle is.

Also, if you can't get an actuator that is the correct length, just get a longer one and chop a bit off with the angle grinder.

 

[RimaNTSS]

2 Vipersan

if you drill the hole where the red circle is

As I've predicted - need to drill another hole 2
But now you already have 2 holes in the main body of frame, so it is much easier to attach plate. And, for sure, it is not necessary to get bigger or smaller actuator.

 

[Vipersan]

Cheers Huevos .
I'll try your suggestion re drilling the 'red' hole ..after all I only need a small amount of extra movement.
..The 'snip' was something I was trying to avoid ..simply because it would be a newly ordered actuator ...and certainly would void any warranty ..lol
Cheers for you input buddy ..
I'd still like to know the _actual_ measured length of what is claimed to be a 36 inch actuator if someone could measure one for me ?
rgds
VS

 

[RimaNTSS]

Some time ago I have got 36' heavy duty actuator. It is simply - HUGE! So, I am just afraid of it, at least will not use for antennas less than 2m (but bigger ones I do not have yet). Can measure 36' tonight.

 

[Huevos]

I'd still like to know the _actual_ measured length of what is claimed to be a 36 inch actuator if someone could measure one for me ?

It's going to be 12" longer than a 24" stroke one. So just close your one all the way and measure it, and add 12".

 

[Vipersan]

Both Huevos and Rimas Ideas are sound ..as is the Snip offered by CH ..
My worry is that inorder to fit the existing actuator (24") to a new position either by drilling another in line hole ..or indeed a plate ...would require moving the whole actuator backwards ..say an inch or so in the Rose..to still access 58 West when fully closed..
This I cannot do as I'd have no outer actuator sleeve to grip ..
I'm already gripping the jack as far away from the motor as I can .
So I'd also have to mount another plate on the polar mount set back a little before I'd be able to do this.
..and by doing this ..would the actuator at full extension then reach 60 East ?
In other words ..would the stroke length be long enough ..?

 

[Vipersan]

It's going to be 12" longer than a 24" stroke one. So just close your one all the way and measure it, and add 12".

Agreed ..it it were that simple ..but Is a it actually 36 inches ?
Or is it actually 30 inches (stroke length)..and 6 inches for the motor ?
Making a total length of 36 inches ..
One web site says yes ..another says no.
I guess I'll phone Red apple and ask em to measure one.

 

[Huevos]

Post some pictures of the other end of the actuator where it meats up with the polar mount.

It's pretty easy to work out all your angles with a bit of trigonometry, especially as two sides of the triangle are always the same. When I was playing with mine I wrote a bit of software to work out the angles across the whole arc and see how fast the dish was moving past any given point.

 

[Vipersan]

Seriously ..Thanks to everyone for their input on this ..
In truth I suspect I might need a slightly stroke length ..not just repositioning of the jack..
But am limited by clearance behind the dish for a substancially longer actuator.
It's a helluva jump from 24 to 36 inches ..
Pity they didn't go in between at 30 ..which would have been perfect for me.
The snip is always an option ..but am loathe to do this on a new expensive heavy duty jack.

 

[Huevos]

Agreed ..it it were that simple ..but Is a it actually 36 inches ?

It's 36" stroke (or should be). So the distance between the 2 spherical joints increases by 36". If you've seen one marked as 30" my guess is that it will be a 24" stroke, which is what you already have.

 

[RimaNTSS]

I suspect I might need a slightly stroke length ..not just repositioning of the jack..

To mess it up little bit more, I would declare that it is possible to get the same arc on your antenna even with 18' actuator by proper repositioning of the jack.
Only thing what can go bad is that antenna will not be able to stand big wind loads. So, again, it is more than enough to use your existing actuator, you only need to reposition of it's fixing points.

 

[Vipersan]

Well ..here are some photos of from above as much as possible ..
You can see how the actuator is mounted and why it was moved outward from the polar mount with a steel bar ..to allow for access to the arc beyond the pole and mount ..otherwise the jack would be obstructed by the mount itself.
..or the motor would have to be moved to the other side of the mount to get that half of the arc.
Hope that makes sense.
3 positions photographed 55W ..1W ..and 50 East ..
Re-locating the jacks fix point now prevents 60 East access ..as the jacks stroke length is not long enough..
rgds
VS

 

[RimaNTSS]

Nice pictures! I still think you need another fixing hole. Go back to post #21, truth is somewhere there, maybe red, maybe green or blue :-shifty

 

[RimaNTSS]

I'd still like to know the _actual_ measured length of what is claimed to be a 36 inch actuator if someone could measure one for me ?

I've measured mine, and that part is 117cm

 

[Vipersan]

Thanks for that Rima ..
much as I suspected then .. about 46 inches ...and much too long ..
So I guess I'll be buying another 24" jack ..and try and engineer those extra few degrees using the various suggestions made in this thread.
rgds all
VS

 

[sonnetpete]

VS....you probably realise I'm not familiar with actuators and jack arms (I've led a very sheltered life) however, how possible would it be to extend the rose joint end of the actuator? I was thinking of a rose joint with extended thread.....or maybe I'm talking rubbish as usual...

 

[Huevos]

Looking at the pictures I think the easiest option would be to modify the polar mount where the actuator attaches. No need to change actuator.

Pete, the quality of these things is crap. The spherical joint is just pressed into the tube and then centre punched from the side to stop it turning. Anyway adding a screw joint would make the situation worse as the actuator is already at the limit of adjustment when closed.

 

[Huevos]

I'd put the holes something like in my picture. It would get the actuator away from the polar mount and also you wouldn't be right at the end of your adjustment limit. Also moving that hole further from the dish would mean the actuator wouldn't swing left to right so much.

Edit: Btw, another option would be use the same holes you are using now but raise the actuator so it above the polar mount. Might need a bit of thought so it doesn't interfere with the elevation actuator.

 

[Vipersan]

I'd put the holes something like in my picture. It would get the actuator away from the polar mount and also you wouldn't be right at the end of your adjustment limit. Also moving that hole further from the dish would mean the actuator wouldn't swing left to right so much.

Edit: Btw, another option would be use the same holes you are using now but raise the actuator so it above the polar mount. Might need a bit of thought so it doesn't interfere with the elevation actuator.

I'm liking your thinking Huevos..
I have to buy a new jack anyway as this one has seen better days..
I'll opt for a heavy duty 24 ...and ponder your suggestions when it arrives.
cheers all
VS

 

[Lazarus]

Could be time to rename that Dish, VS: A big, butch thing like that needs a meaty, masculine handle - how about Cassius? Or Claire?