Positioner Suggestions? 12' Unimesh on AJAK 180 H-H Mount

[phlatwound]

I installed a 12' Unimesh dish on an AJAK 180 H-H mount a few months back and am looking for some suggestions on a positioner unit.

I already owned and have tried a G-Box and a V-Box on this behemoth, neither seems to have the cajones required to swing it. Both of those devices will take the dish about 20-25 degrees either way from apex and slowly bring it back, but I need to be able go around 50 degrees to the east and west from my 93 degree true south location.

I had never had any issues driving a BUD with a G or V-Box in the past, but had never tried using them on a 12' dish before. At first I thought I may have internal issues with the AJAK, but I knew it was well cleaned and lubed, and that it had run fine on my bench with no load. And I had the -Boxes close-hooked to the motor on about 6' of 16 ga. wire so didn't think that was the issue.

I came real close to pulling the dish off the mount and removing the mount for troubleshooting when I remembered I had an old MTI 2800 positioner box. I hooked it up and voila, was able to run the dish from limit to limit (AJAK internal limit switches)...a little slow bringing it up from the extremes, but it will do it. I would just use the MTI but it has no remote, and the display is out of it, would like to have both of those items in whatever I can come up with.

I believe my 3 choices are:

1.) Old-school standalone positioner box? I would not mind using one of these, just tune to a hot tp and watch my meter for peaking, but would like it to have a remote control, and some sort of display...ideas?

2.) Analog receiver? I still use a Toshiba 1820 to drive my first BUD (installed in 1993) and it has been bulletproof, great unit. Pretty sure I could drive tent stakes with it and not hurt it.

I have a spare 1820 but the problem with this model Toshiba (AFAIK) is you need an analog signal on each sat that you want to save a position for, once a signal is locked the receiver then goes through an autopeak and autoskew routine, and then it saves the position. It also only will display one letter and one number for the position (G5, W2, T4, etc.), it does not have a numerical readout that can be correlated to a position. The 1 letter/1 number display is not a deal-breaker though.

I have no experience with any other analog receivers, is there an analog unit that you can use like a G-Box...that is, move it from sat to sat, use a digital receiver to peak the signal, and then save the sat position in the analog receiver? And preferably with a numerical readout to visually see the position and dish movement?

3.) 4DTV receiver? I know nothing of the Motorola 920 & 922's but I have read on the forum about them. It sounds like with the new maps you are able to have quite a selection of sat locations, but I don't know what they all are, or how much the user can define them, if any. I would like to be able to have all locations from around 40W to 139W, if possible. I do not need the unit to be authorizable, but it would need to be capable of receiving the new maps (tiles?).

Also, I do not need to be able to control a servo, I am using a SatAv C2 right now, and may go C-band ortho in the future.

Does anyone know of anyone with a 12' Unimesh on an AJAK 180 that is running with a G or V-Box? I suppose I could have issues with my mount but since the MTI runs it ok I really think the little China-boxes just can't push enough juice to run this big boy.

Any ideas, thoughts and/or suggestions are welcomed.

 

[primestar31]

Build a small box with two 24volt (coil) RELAYS in it capable to handing at least 6 amps at 36 volts on their switches.

The V-Box runs the relay COILS for either East or West, so almost no load on the V-box.

On the switch side of the relays, you hook up the transformer from an old-school positioner, that can crank out 6 amps or so. Or, build a power supply yourself that can handle that. All you need is a transformer, and a bridge rectifier from Radio Shack. You might even consider an electrolytic cap across the rectifier to smooth the voltage a bit, but I don't think that'll be needed in this application.

There you go, and you aren't even breathing hard yet!

If you put the relay box at the dish in a weatherproof box, you'll only need heavier guage wire from the relays to the H to H motor.

 

[Anole]

more power, Scottie!

Yea, you're just not delivering the current required.
The little units power supply sags under load.
I'd just put a gutsier power supply under it.

First step would be to measure voltage and current under heaviest load, or at stall.
From there, it should be all down hill.


btw, your analog receiver probably puts out 36v.
A 4D receiver only runs 24v, but probably doesn't sag under load.
You could use either to feed the V/Gbox relays as a test to prove the theory.

 

[phlatwound]

Thank you both for the ideas.

I should have mentioned in my original post that I am electronically...mmm...challenged.

Had to find out the hard way which end of a soldering iron to grab.

I would prefer to find more of a "turnkey" solution but I can think of one aspect of going this route that may make it more attractive to me....

Would this allow me to use Diseqc 1.2 positioning, that is, having the receiver control the G-Box for positioning?

 

[primestar31]

Well, perhaps you have a friend with electronics experience that will build the relay box for you for trade of some sort....
You pay for the parts, and he just assembles and solders it together

Maybe he needs a spare dish or something, or even a 12 pack of beer, or $$ something like that.

I'd think that the V-box used in this way would still properly get the positioning feedback as normal. That part of the circuit wires shouldn't need any changes. UNLESS of course the H to H is a 3 wire Optical setup, in which case you might want to convert that to a two wire reed switch which you could swipe out of an old unused linear positioner.

 

[FaT Air]

Counter balance the dish??

 

[phlatwound]

Well, perhaps you have a friend with electronics experience that will build the relay box for you for trade of some sort....
You pay for the parts, and he just assembles and solders it together

Maybe he needs a spare dish or something, or even a 12 pack of beer, or $$ something like that.

I'd think that the V-box used in this way would still properly get the positioning feedback as normal. That part of the circuit wires shouldn't need any changes. UNLESS of course the H to H is a 3 wire Optical setup, in which case you might want to convert that to a two wire reed switch which you could swipe out of an old unused linear positioner.

Yeh, one of my brothers could handle this project with ease, if I was to go that route.

And back to what you mentioned earlier, if I was to locate the "hi-power" relay unit out at the dish, I suppose it would also require 120 VAC out there also?

Both of my AJAK mounts have reed sensors already, no optical.

 

[phlatwound]

Counter balance the dish??

Interesting idea there, not really sure how that would work.

Anyone have (or seen) pics of a counterbalanced dish?

 

[primestar31]

Yep, you'd need power out at the dish if the relay unit was located out there to save on heavy gauge wire.

However, you could just run a heavier gauge wire from your house, (or maybe the dish is closer to an out building that you can get power from just for this circuit?) and have the relay box located there. Whichever is easiest and cheapest. I don't know how long a wire run you have for your dish, but the wire would need to be capable of pushing 36 volts at 6 amps or so that whole distance. Most likely something like a 12 gauge wire minimum at around 100 feet or so. Sprinkler wire won't cut it. I'd think you could easily use standard Romex for that and run it through some black plastic pipe so it doesn't get shovel-cut next time you are working on the yard.

I don't think any sort of counter-balancing can work with an H to H mount. It can work with a linear positioner though, as there's enough leverage on either side of that sort of mount. That sort of leverage just doesn't naturally exist with an H to H mount.

 

[phlatwound]

Ok, well running power out there is part of my "Master Plan" anyway, will probably need it for some multiswitches also. And it will be nice not to run an extension cord from my shop every time I want to set up out in the dish farm.

Yeh, I don't have a clue how to counterbalance, or if it is even possible. Seems like I saw a picture of a big dish once that had a weight standing off the back of it, not sure what kind of mount it had.

Best part it is there is no hurry to do this, digging a new ditch for conduit through our clay/rock (actually that should be rock/clay) is gonna be a bite in the rump.

 

[primestar31]

Nobody says you HAVE to bury the cables. My first c-band dish back in the mid '80's, I ran the wires the 100ft and tied it every so often to the tops of wooden stakes I drove into the ground to keep it off of the grass.

Caused a little issue when mowing, but worked perfectly.

 

[FaT Air]

Counter weighted dish, HtoH mount also. http://www.carrollsweb.com/dgerst/sat.htm (pic 2)

 

[phlatwound]

Nobody says you HAVE to bury the cables. My first c-band dish back in the mid '80's, I ran the wires the 100ft and tied it every so often to the tops of wooden stakes I drove into the ground to keep it off of the grass.

Caused a little issue when mowing, but worked perfectly.

These 2 are just praying that I would do that!

 

[phlatwound]

Counter weighted dish, HtoH mount also. http://www.carrollsweb.com/dgerst/sat.htm (pic 2)

Thanks Fat, that is perfect. Not the pic I was thinking of earlier, but I remember seeing that one also. Looks like it would be pretty easy to fab something like that. At first glance i would have guessed that to be an AJAK but says it's a Proform.

Found a thread on the forum from 2008 about that mount:

http://www.satelliteguys.us/threads/147859-Seeking-Pro-Form-H-180-Mount

And here's the pic:

 

[primestar31]

Counter weighted dish, HtoH mount also. http://www.carrollsweb.com/dgerst/sat.htm (pic 2)

WOW!

That is really quite elegant!

The best engineering solutions are always ultimately so simple that most people over look them because we all tend to over-think things at first.

 

[johann12]

Counter weighted dish, HtoH mount also. http://www.carrollsweb.com/dgerst/sat.htm (pic 2)

Something like that could work very well for most C-band dishes to make it easier to bring dishes back from the far east or west. It would also balance dishes for being front heavy.

 

[Anole]

3 car batteries?

While I don't disagree with the ideas above, I'd take a slightly different path.
I would mount a substantial 4..5 pin connector on the back of the Vbox.
Inside the Vbox, I would break the connections from the power supply to the relays.
(that 36-50 volts isn't used for anything else)
Then run the power plus and minus to two pins of the connector.
Assign two more pins and hook them inside the Vbox where the 36v power used to go.
Take a mating connector, and wire the plus power to plus relay.
Likewise, wire minus power to minus relay.
This restores normal wiring and function to the Vbox, if the connector is plugged in.

To use an external power source for testing (or permanent) wire plus & minus from your auxiliary supply to only the relay plus & minus pins.
Now, the Vbox internal supply is unloaded.

You can experiment with various supplies or batteries to see what works best.

 

[Lone Cloud]

What a behemoth!

I was going to suggest a counterweight but see that others beat me to it. Please let us know when you get the first signal from Vega

 

[Magic Static]

One other area to look ar would be the the main shaft of the AJAK. Is the grease all dried up? I totally pulled mine apart and cleaned and regreased with synthetic grease. Both the VBox and GBox move the 10' Winegard Pinnacle on the AJAK very well and quickly. And that's a heavy dish. The motor on the AJAK is rated at 30 volts. A 24v or 36v mover should be fine.

 

[Anole]

diagnose first

I suppose if you had a blown diode in the motor power supply (of the Vbox ), it would under perform.
Should have a working full wave rectifier (of two or four diodes) between transformer and filter capacitors.
If one is popped, you get only half wave rectification.
Some voltage and current measurements are necessary.