Precision Polar Mount Project

[RimaNTSS]

I've been looking at Ajaks and they seem pretty beefy. However, I read somewhere that it's only 8 pulses per degree?

In Ajak manual there is one picture - 3m glass dish mounted. For pulses there is 5-magnet wheel installed, butit is possible to change the wheel with more magnets, and there you go - pulses/degree double or triple.

 

[beavs2112]

I've been looking at Ajaks and they seem pretty beefy. However, I read somewhere that it's only 8 pulses per degree?

AFAIK its 10 pulses per degree. Here's a copy of the AJAK H180 manual in case anyone is interested.

 

[Channel Hopper]

And today I've been reminded why 1224 rules the roost. The jack that I am using is rock solid - there's only a teeeny bit of play in spheric joints but nothing major beyond that. However, with that on, there's far more play at the extremes (west for me) than there ever was with the Jumbo. Yes, it is more solid in the middle and the east of the arc but... sigh. I can only get down to 49 east until the mount runs into itself. Not a huge deal as I can't see beyond 53 east anyway... and I don't actually know how far west I can go. It looks like 58W should be OK but this is guess-work and the dish is almost about to flop at that extreme.

Lastly, the resolution of this SuperJack XL HQ or whatever it's called, is pathetic. around 10 pulse counts per degree! Which makes it rather prone to miscount. Compare that to 1224, which is about 25-30 counts per degree. Looking online, that ball screw Venture is about 15 pulses per degree (depending on where you are on the arc, of course)...

Ahhh... now the dilemma of whether to put the Jumbo back on or live with this.

Yuu need to move the actuator as far from the pivot as you can to improve the stability at extremities, using some decent angle iron welded to the mount, both at the rear and to the side nearest the East . Unfortunately this means getting a longer arm to traverse the arc, but there are plenty of reasonable /good jacks out there.

 

[Captain Jack]

You're right. CH. I need to move the jack mounting point a bit back and to the side. I also need to move the mounting to the west side as that's where the dish will spend most of its time hunting out C band. Still need stability on the east side though.

If you have any good jacks in your shed, let me know! I'll bring you a souvenir from Saratov...

 

[Trust]

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I totally agree with your findings re: the jacks, i loved my Jumbo on my 2.2 ali Precision dish with counter balance at the rear, but even that got trashed when a storm came and i wasn't around to lower it all down. This Channel Master 1.8 with all it's lnb's on the changer would have been too much for another Jumbo to handle and thats why i had to go for the stronger but not preferred option of heavy duty jacks .
I'd love to go for an Egis or even a home brew version of an Egis for peace of mind.
I recon you would be ok with your Jumbo on your Lami installation with a rear counter balance fitted, and install some extra ground anchor points either side of the dish to tempory tether it to in the event of any strong storms..... just my two cent's worth.

Only issue , you need a polaraiser .
I got my hand on a few very heavy worm gear boxes , managed to make it play free .
They use to be on truck trailors , loading bricks packages with a weight of more than 2000 kg
Try to make H2H rotor from it for BIG dishes .
Now I'm searching for motors .

 

[Captain Jack]

Welp, I moved the jack arm to the other side as well as move the mounting point back a bit. I need to replace the bits with INOX as these are all I had... the good news is that I am able to get from around 58W to 53E. The dish can actually go beyond 53E but trees/houses are in the way. The other good news is that my 24" jack is enough to cover this distance. It's still not as stable at the extreme but is better.... No pictures yet (it's peeing it down) - will post those later.

 

[John]

Welp, I moved the jack arm to the other side as well as move the mounting point back a bit. I need to replace the bits with INOX as these are all I had... the good news is that I am able to get from around 58W to 53E. The dish can actually go beyond 53E but trees/houses are in the way. The other good news is that my 24" jack is enough to cover this distance. It's still not as stable at the extreme but is better.... No pictures yet (it's peeing it down) - will post those later.

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Did a similar thing the other day as well to attempt to increase the stability on the very extremes, about 60 East absolute max. Moved the pivot point to the outer hole on the rear bracket which has increased stability. Also prior to moving the fixing point the 36" jack was drawing about 2.8 or so amps and the Moteck positioner didn't like it one bit and would quite easily go into "Err" mode. Moving the fix point has 99% cured that. Pic shows dish at 57 East.

 

[Phoenixx]

Distance from the pole to the under site from the acctuator are to small. The force is to much when you get in the critical angles, and also the steps / pulse has more variation to the signal when you go to outside angles. Solution is to get more distance between polarmount and pole and get a 36 inch for rotating and
replace the upper actuator to a smaller one to get lower the wight of the antenna.

 

[John]

Distance from the pole to the under site from the acctuator are to small. The force is to much when you get in the critical angles, and also the steps / pulse has more variation to the signal when you go to outside angles. Solution is to get more distance between polarmount and pole and get a 36 inch for rotating and
replace the upper actuator to a smaller one to get lower the wight of the antenna.

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Run that past me again .... I'm all for being taught something ..... possibly with some superimposed corrections you advise laid over the pic.
The E-W west actuator is already a 36", the 24" HD one used for inclination is one that was a spare here so it got used.

 

[Spiff]

And today I've been reminded why 1224 rules the roost. The jack that I am using is rock solid - there's only a teeeny bit of play in spheric joints but nothing major beyond that. However, with that on, there's far more play at the extremes (west for me) than there ever was with the Jumbo. Yes, it is more solid in the middle and the east of the arc but... sigh. I can only get down to 49 east until the mount runs into itself. Not a huge deal as I can't see beyond 53 east anyway... and I don't actually know how far west I can go. It looks like 58W should be OK but this is guess-work and the dish is almost about to flop at that extreme.

Lastly, the resolution of this SuperJack XL HQ or whatever it's called, is pathetic. around 10 pulse counts per degree! Which makes it rather prone to miscount. Compare that to 1224, which is about 25-30 counts per degree. Looking online, that ball screw Venture is about 15 pulses per degree (depending on where you are on the arc, of course)...

Ahhh... now the dilemma of whether to put the Jumbo back on or live with this.

Have been reading this thread with great interest.

Just a thought would not adding another reed switch the other side of the magnet wheel wired in parallel double the count ?
Regards Allen

 

[moonbase]

Have been reading this thread with great interest.

Just a thought would not adding another reed switch the other side of the magnet wheel wired in parallel double the count ?
Regards Allen

One option to get more sensitivity with an actuator would be to replace the magnetic wheel with a wheel with more magnetic poles on it. Each time a magnetic pole rotates past the detector it registers a pulse, or at least that is my foggy understanding of how it works. The other option would be to get an actuator with an optical switch.


Rgds

 

[Spiff]

One option to get more sensitivity with an actuator would be to replace the magnetic wheel with a wheel with more magnetic poles on it. Each time a magnetic pole rotates past the detector it registers a pulse, or at least that is my foggy understanding of how it works. The other option would be to get an actuator with an optical switch.


Rgds

Yes that is another way of doing the job : )
Have just ordered a gold plated wall mount see pic £274
With a 3 metre pole, it took me several days to part with the money, I shall have to rest : (

 

[Captain Jack]

Ouch! I was lucky... I got this package for free... came with Precision 90cm dish and 1224 motor...£130.

 

[Spiff]

Ouch! I was lucky... I got this package for free... came with Precision 90cm dish and 1224 motor...£130.

Bargain.

This mount though has got to hold a 1.4m aluminium Triax dish or a 1.3 Precision dish, on a Precision mount with two jacks 50 yard South of the sea in Mullion Cove, so I can sleep at night : )

 

[John]

Yes that is another way of doing the job : )
Have just ordered a gold plated wall mount see pic £274
With a 3 metre pole, it took me several days to part with the money, I shall have to rest : (

Nice bracket & pole Allen ...... hope those lads in the picture didn't fix it on that position shown in the pic though

 

[Captain Jack]

South of the sea in Mullion Cove, so I can sleep at night

Nice spot. We are going down to Flushing (the one opposite Falmouth) for a week tomorrow, so will probably visit nearby. Shame Goonhilly is no longer open to visitors

 

[Spiff]

Nice bracket & pole Allen ...... hope those lads in the picture didn't fix it on that position shown in the pic though

It will be above the railings to the right after I move the weather station.
Not sure how Alanna is going to drill all those fixings on a double extention ladder but she is a strong girl : )

 

[Captain Jack]

Take care with that PM - it's freaking heavy.

 

[John]

It will be above the railings to the right after I move the weather station.
Not sure how Alanna is going to drill all those fixings on a double extention ladder but she is a strong girl : )

I like your style Sir

 

[archive10]

This mount though has got to hold a 1.4m aluminium Triax dish

Did you buy the one off E-bay a week or two ago?
Or is this a storage-piece...?