USB connections and radio communication don't get along


Here’s the situation: my tractor has a radio communication device. Incoming radio messages are not a problem, and individual short outgoing ones are fine too. However, long outgoing messages or several short outgoing messages in quick succession result in the connection to the Autosteer board being interrupted. As a result, I have to reconnect in the AIO.

Here are some key details about my setup:

TrekStor Wintron 10.1
Autosteer CC board
Connection via a shielded USB cable
Motorola GM340
Frequency between 158-162MHz

What would be sensible measures to take? I probably won’t be able to implement everything, but any advice is greatly appreciated.


With usb it is very important to have same GND. On one tractor we had problems with usb disconnecting. Reason was: Charger for tablet was inserted in cigarette lighter plug. And steer pcb and other steering items were connected directly to battery. So two different GND!

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In my case, too.

The tablet runs through a built-in 3-pin socket in the cabin. The circuit board is connected through the main power supply of the cabin.

The most sensible solution would be to integrate the tablet into the wiring of the circuit board. I will test that.


Yes do charging from auto sterring board

I do it since the begining and no trouble with usb of deconnexion anfd it will be more easy to use

as larverst say common ground is really important !!


But it’s really peculiar for someone with only rudimentary experience in electrical and electronic matters. Because, strictly speaking, my tractor has only a single ground – the battery’s negative pole.

I just had a thought. The ground for the tablet and the PCB definitely connect to different points on the cabin’s ground. That could be it.

That is basically correct----BUT
Cigarette lighter gnd has it´s gnd connected to a bolt with several gnd´s somewhere in the cabin, then cabin is connected to tractor body with a wire. then from body to battery negative.
If you make a gnd directly from battery to PCB then there will be different resistance which will give maybe 0,2 V difference between the two gnd´s. USB do not like that difference. And even worse if one of the connections are corroded/rusty.
Can be solved by cutting end of charger and connect directly to same wires as PCB, or buy a loose cigarette lighter female plug and connect that to same wires as PCB.

I would prefer not to run a cable from the battery to the cabin, as I don’t have any available pass-throughs, and I am hesitant to drill holes in the cabin floor. However, if both the tablet and the PCB use the same positive and ground points, that’s already better than before.

Or is a direct battery connection absolutely necessary?

Same would be sufficient :smiley:

I will change the wiring harness and test.

I have another issue with the F9P antenna and the roof headlights in the cabin ceiling.

I hope that this issue will also be resolved with it.

Otherwise, I will bother you with it as well.

In any case, thank you for the advice and the explanation.

I was also having some usb drop outs last season, I charge the pokini tablet from a power bank by micro usb, but I think i had some drop outs when it wasn’t plugged in charging also. Any ideas what this might be caused by?

If I understand you correctly, your tablet is connected to a power bank, and the control is powered conventionally with 12V, is that correct?

My first question would be, why the power bank? What do you aim to achieve by using it instead of directly using a charger?

In my case, I’ve “only” taken 12V from two different points within the cabin for the tablet and control. With the power bank, you have two independent power sources (tractor battery and power bank) that don’t share a common ground.

I’m not an expert as I face similar issues, but the advice given to me can also be applied here.

Correct yes, i was using the power bank because i had no power socket free in the cab for most jobs. It was from reading this thread that i realised a potential problem with having different power supplies, i will take power from the pcb input then for the tablet and see how that goes.

That sounds like a good plan. I’ve heard from others that computers really don’t like voltage fluctuations. The USB port, in particular, reacts quite sensitively to that. A good power supply is supposed to be able to compensate for this, as well as the integrated battery. How to recognize a good power supply… No idea! In my case, the power supply is a simple DC/DC converter und the battery is completely worn out. The tablet can’t last more than 5 minutes without a charger, It could well be that this also leads to problems.

Just wanted to make sure you’re aware of that.

Just to throw more into the mix: laptop power supplies have caused issues too. For some (rare?) supplies the output ground is not the same as the input ground.

Good to know

Do you know if and how one can check if the input ground and output ground of power supplies are identical?

I suppose you could do an ohm check between the input and output ground with the adapter unplugged from anything. Followed by a volt check from tractor ground to laptop chassis (the metal cage around a usb or Ethernet port). That should tell you.

I connected the power supply of the tablet to the supply line of the circuit board.

The issue with the headlights in the roof seems to be history. I switched the lighting on and off several times while the control was running on the Farmyard. No reaction.

The control still responds sensitively to my radio. If I transmit too often or for too long, the Autosteer part of my control goes red in the AIO, and I have to disconnect and rebuild the connection.

Any other ideas?