STAB 90 Dish Motor Needs More Power!

[Christopher Cromwell]

Early Thursday, I began testing a brand new Zgemma H7S Satellite Reciever from Air Digital Ltd. for my Ku Band motorized dish. This is the first Enigma 2 Open Firmware based Reciever I have ever used and so far it's a real beauty!
The Zgemma H7S has three hybrid tuners inside, 2 for satellite, and 1 for cable TV; also supports Diseqc and USALS motor control.
I downloaded the best plugin I could find to provide me the satellite list for the H7S.
I have a 85+ foot cable run to the STAB 90 motor, and I know the H7S is providing the LNB with enough voltage to scan and bring in channels.
The bad news is that the H7S Reciever is powered by a 2A wall adapter, and there's not enough current to drive the dish motor. If the dish motor moves at all, it's extremely very slow, otherwise the motor doesn't do anything. I have the tuner setting set for more voltage going to the motor, but still little to nothing.
Is there a powered switch or power Inserter I could connect somewhere to help the Zgemna H7S safely drive my dish motor?
For now, I'm using my Linkbox 9000i to drive the dish motor separately through a Splitter, it's a pain going back and forth, but it works. I'm guessing the Zgemma H7S might do better with a little smaller plastic gear motor, but not sure. I can try to post pics later, but thanks for letting me know.
By the way, I did put my motorized dish on the side of the house a month ago, I missed my NHK World too much.

 

[KennyR]

I had a problem with mine being slow years ago and this bolt was to tight ,just have it snugged down now. may not help your problem but worth checking to see if it will help. I think it was binding the gears on mine and causing really slow movement.

 

[a33]

So, the Zgemma has an active current limiter, I guess, when you have no problems with your other receiver and use good quality copper cable, and when increasing the voltage doesn't really have an effect.

I know of three ways of external power inserting for a motor, see for instance Antenna motors - power consumption (and the complete topic).
Problem is, when you also feed 13/18 Volt for the LNB through your cable, that you need an extra cable between house and dish for the motor power.

So I would probably first measure the current needed for LNB and current for motor, and if LNB current is high I would choose another LNB with lower current to see how much that helps.
I don't know if somebody has tried altering the current limiter in the Zgemma?

Greetz,
A33

 

[Christopher Cromwell]

I know of three ways of external power inserting for a motor, see for instance Antenna motors - power consumption (and the complete topic).
Problem is, when you also feed 13/18 Volt for the LNB through your cable, that you need an extra cable between house and dish for the motor power.

So I would probably first measure the current needed for LNB and current for motor, and if LNB current is high I would choose another LNB with lower current to see how much that helps.
I don't know if somebody has tried altering the current limiter in the Zgemma?

Greetz,
A33

Yeah, running another cable around the house for the motor won't be too feasable. I do know the Zgemma H7S has two Voltage Regulators and several or more Electrolytic Capacitors on the board as well as three fuses. I don't have a schematic to know what does what causing the low current for the motor movement.

 

[Christopher Cromwell]

So, the Zgemma has an active current limiter, I guess, when you have no problems with your other receiver and use good quality copper cable, and when increasing the voltage doesn't really have an effect.

I know of three ways of external power inserting for a motor, see for instance Antenna motors - power consumption (and the complete topic).

Greetz,
A33

Theoretically a two way splitter with a DC power path on one side used in reverse could be tried, the DC power side goes out to the LNB, the power isolated side could go to a DC power inserter to run the motor, this way Diseqc commands to move the motor will go to the motor and any DC voltage switching commands would go to the LNB.

I have never tested this setup and do not have the lab equipment anymore to do so, so it's a try at your own risk.

I was daydreaming of this kind of solution earlier today, but haven't tried it yet either. It might work.

 

[Christopher Cromwell]

 

[a33]

Theoretically a two way splitter with a DC power path on one side used in reverse could be tried, the DC power side goes out to the LNB, the power isolated side could go to a DC power inserter to run the motor, this way Diseqc commands to move the motor will go to the motor and any DC voltage switching commands would go to the LNB.

Oh yes, this would absolutely work.
Even 'cleaner' would be a socalled 'diplexer', meant to mix or unmix satellite signals and FM-signals (or also terrestrial TV, I believe?), as the signalpath for FM is good enough for 22kHz diseqc signals, and you would hardly loose satellite signal from the LNB path. The LNB path of a diplexer is both ways DC through, by the way.

For inserting the external power directly to the motor: as can be seen in the links I mentioned, it could be that you would need an extra coil of some sort in the external power path. Or maybe something to keep the impedance of the 22kHz signal where it should be.
Maybe a 'power inserter' has more complex parts than just a capacitor and a coil, as used in the DIY example in the links? I never quite understood why there sometimes arose problems on that part: that the motor didn't respond to the 22kHz signal. With other examples, I saw no problems reported.....

Keep us posted on your trials!

Greetz,
A33

 

[a33]

Just a thought experiment:

Assuming the receiver voltage for motor and LNB goes below 10 volts when the motor is running (and the current limiter is active), you could maybe feed an constant external voltage of say 11 volts to the cable via a diode; while when receiver voltage goes up to 13/18 volt again, the receiver voltage (also with diode -- for protection) takes control again.
Then you would still only need one cable to motor/LNB!
Only disadvantage is, that the motor has only about 11 volts to run, and you cannot set it to an external 18 volts. But you bypassed the current limiter, nonetheless.

Point of attention would be, that the 22kHz of course should pass that self-built "inserter".
And you should add a fuse or some current limiter on the external power source, as well.


Have you measured the voltage on your receiver, with running motor (on horizontal transponder, and on vertical transponder), and without running motor?
I would be interested in the values.
Maybe inserting a constant 12 volt or 12,5 volt would also be possible...

greetz,
A33

edit: small additions.

 

[jorgek]

I had the same issue as KennyR reported re too much torque on the bolts. What is the current rating for this receiver. The Stab does not draw that much current. Also try switching to a horizontal TP when driving the motor. The higher voltaqe will speed it up.

 

[Christopher Cromwell]

I had the same issue as KennyR reported re too much torque on the bolts. What is the current rating for this receiver. The Stab does not draw that much current. Also try switching to a horizontal TP when driving the motor. The higher voltaqe will speed it up.

I don't have a current rating for the Zgemma H7S, there is nothing mentioned on the back panel or the specs elsewhere. But I do now have much better news, I found a solution to my dish motor problem!

I wasn't exactly happy with the OpenATV 6.0 firmware, so a good while ago, I reflashed the Zgemma H7S receiver with OpenPLi 6.0 Release Candidate firmware to check it out. That OpenPLi Firmware scans in channels much better than the OpenATV firmware did and the best part is the different firmware now moves my STAB 90 Dish Motor much faster!!! I guess the OpenATV firmware had a motor driver that wasn't working too well or something. So there's actually nothing wrong with the box, it was the firmware I was using. I'm going to try OpenSPA firmware for it next to see how well that does.

 

[hank123]

Happy your issue is fixed.

Back to the power passing splitters, Directv has them. Would you use one on both ends and use a fixed power source?

 

[Jason S]

Theoretically a two way splitter with a DC power path on one side used in reverse could be tried, the DC power side goes out to the LNB, the power isolated side could go to a DC power inserter to run the motor, this way Diseqc commands to move the motor will go to the motor and any DC voltage switching commands would go to the LNB

Back to the power passing splitters, Directv has them. Would you use one on both ends and use a fixed power source?

Here's a link for what I tried a while back. It worked with one receiver, but not another. For the receiver it did work with, there was a separate 20v power supply for the motor without tapping into the motor or any other external mods.
Wiring up my next project

 

[Christopher Cromwell]

I've only used a Power Inserter once to drive more voltage to my C-Band LNBF. I Thankfully I don't have to go through all that now. The OpenPLi Firmware is I'm using is working much better, even though it's a Candidate release.

 

[Christopher Cromwell]

Late last night I scanned in all of the Ku Band channels from 103W, blind scanning only takes two minutes!! Fast!!! But the best news is that this Zgemma Receiver with OpenPLi Firmware is in fact able to bring in not only AC3 Audio, but also bring in Dolby E Audio as well on some channels like NBC Feeds! Just press the Audio button on the remote and choose the Audio Channel that contains the sounds you want to hear; like people speaking! Very beautifully made receiver!! I'm guessing I'm the only one in the US that has a Zgemma box.

 

[a33]

... and the best part is the different firmware now moves my STAB 90 Dish Motor much faster!!! I guess the OpenATV firmware had a motor driver that wasn't working too well or something.

Well, that is a surprising outcome!
I'm curious what a firmware does in the motor-control? I allways thought that voltage and current was a hardware matter, apart from (maybe) bi-directional diseqc matters (diseqc commands, with diseqc-feedback from the receiving apparatus).

Does someone know, how firmware influences motorcurrent?

Greetz,
A33

 

[jorgek]

Some receivers are capable of switching the motor drive voltage to 18v everytime you move the dish regardless if you are on a Vertical or Horz TP.

 

[Christopher Cromwell]

Exactly! For the new Enigma 2 receivers, the Open Based Firmware depends on certain drivers and other plugins like Equipment Motor Control to help the box to send out USALS and Diseqc commands properly. If an incompatible driver or slight incompatible Open Firmware is used, certain things won't work at all; just like in the PC. I never heard or used Enigma 2 or OpenAnything ever before, so I figured originally it was the circuit board not supplying enough current. Wasn't until I finally got brave enough to try a much different Firmware like OpenPLi that made the difference. Pretty sweet to have a box like this where your not limited to just one stock firmware like the Linkbox. The Zgemma H7S will work very nicely for the US, the only downside right now is the cost, $200 for the box and $50 for air shipping. Got the box within 3 days of leaving China.

 

[Christopher Cromwell]

I think I'm the only person in the US to have a brand new Zgemma H7S, it was made in April. I'm thinking of writing a full review if anyone is interested, unless they are still happy with the Linkbox.

 

[jorgek]

How about a review of its 4K capability?

 

[Christopher Cromwell]

How about a review of its 4K capability?

It's got it!! Thats why I wanted this box so badly. The Zgemma H7S new dual core 1.7Ghz CPU is capable of processing and displaying 4K UHD Video, and the hybrid tuner is capable of getting S, S2, and S2X Signals. You have two satellite inputs, so you can record one channel while watching another channel. Then the H7S has a 3rd separate tuner for Cable or Terrestrial TV, so three tuners in one box. I don't have Cable TV or a Terrestrial Antenna to test out the 3rd Tuner, and I don't have a C-Band Dish anymore to try on the satellite tuner. But I scanned in the three big Ku Band Satellites within a few minutes, everything came in! Eventually 4K will be coming to Ku Band FTA. It even gets Dolby E Audio on some channels, just press the Audio button to select a different Audio track.