Difference between 'A' and 'C' controllers

astrostar · Jul 27, 2023

I've recently purchased an I1 Pro which came with two controllers, one is an 'A' series whilst the other is a 'C' series. The previous owner had them setup with the master being the 'A' series and the slave as the 'C' series. I've read that the 'C' series give greater power output compared to the 'A' series so I'm wondering whether I should have the configuration reversed ?
Do any other members have the same controllers and if so how do you configure them as master and slave ?

Just found some info on another forum which seems to indicate that the 'C' series controllers have more power output than the 'A' series but if anyone can confirm this in real world tests/usage this will be most helpfull.

Any help greatly appreciated.
Graham

Donnie Frank · Jul 28, 2023

astrostar said:
I've recently purchased an I1 Pro which came with two controllers, one is an 'A' series whilst the other is a 'C' series. The previous owner had them setup with the master being the 'A' series and the slave as the 'C' series. I've read that the 'C' series give greater power output compared to the 'A' series so I'm wondering whether I should have the configuration reversed ?
Do any other members have the same controllers and if so how do you configure them as master and slave ?

Just found some info on another forum which seems to indicate that the 'C' series controllers have more power output than the 'A' series but if anyone can confirm this in real world tests/usage this will be most helpfull.

Any help greatly appreciated.
Graham

I have all three controllers; A, B and C. For the longest time I thought the C series had the strongest Tx/Rx, so that's what I've been using. But then one day at my girlfriend's house I was doing some R&D with my Inspire 1 and I noticed something peculiar with the signal strength.

For context, the controller was in my girlfriend's kitchen. The Inspire 1 was in the back yard about 30 feet away. Between the two was a single wall.

Whatever I was doing at the time, I noticed that there was a LOT of interference going on between the Inspire 1 and the controller. Who knows why? I checked the radio signal histogram. Interference was moderate:

So I found a clear, stable channel, but to no avail. Interference was profound:

So I saw this as an opportunity to see if there was a Tx/Rx difference between the 3 controllers. To avoid confusion, I marked 3 pieces of paper A, B and C, and set them in front of the camera. As you can see, controller C had a lot of interference.

So then I bound controller B to the Inspire. Results were pretty much the same.

So then I bound controller A. The results were quite different and quite dramatic. ZERO interference.

From there I proceeded to go back and forth from A to B to C, and the results were consistent; lots of interference with the B and C controllers. No interference with the A controller.

Needless to say, because of these test results, I bound the A controller to my Inspire and that is the one I have been using. Honestly, I haven't really noticed much of a difference in the field. I essentially use the Inspire at two different locations, both of which have MASSIVE WiFi interference. So for both jobs I use a parabolic signal booster and am very diligent about pointing the antennas directly at the Inspire. But despite my diligence, signal strength will sometimes drop below 100%. I start to get concerned when signal drops below 75%, which doesn't really happen unless I point the antennas away from the drone. So far, after months of using the A controller, I will say that interference has been very minimal, and signal strength hasn't dropped below 95%.

While not truly "scientific," the results are objective. I wouldn't consider my tests definitive, but certainly compelling. Take this information for what it is worth.

D

astrostar · Jul 28, 2023

Hello Donnie,
Many thanks for taking the trouble to reply. Your tests are certainly an eye opener and whilst not 'scientific' in the true sense you can't beat real world tests since this is how we use our drones. It's odd that the 'C' controller has better Tx/Rx than the other two and yet exhibits more interference ! Perhaps some radio buff can step in and explain this apparent anomaly. Just wondering whether the extra 'gain' is also increasing the interference ?
Well your tests show that I'm better off leaving my setup as it is with 'A' being the master and 'C' the slave.
Once again, many thanks.
Graham

Donnie Frank · Jul 28, 2023

astrostar said:
Hello Donnie,
Many thanks for taking the trouble to reply. Your tests are certainly an eye opener and whilst not 'scientific' in the true sense you can't beat real world tests since this is how we use our drones.

Agreed. In lieu of expensive RF forensics equipment, "experimenting" is what we do.

astrostar said:
It's odd that the 'C' controller has better Tx/Rx than the other two and yet exhibits more interference !

I'm not thoroughly convinced the C controller has a more powerful Tx/Rx. I have seen zero evidence to support this....not for lack of looking. And DJI support offers a laughable level of help in anything more technical than how to login to your DJI account.....<:^/

astrostar said:
Perhaps some radio buff can step in and explain this apparent anomaly.

I was hoping the same.

astrostar said:
Just wondering whether the extra 'gain' is also increasing the interference ?

Interference with OTHER RF devices, I would assume so.

Worth noting...

It was later in the game that the FCC regulated DJI drones to decrease their RF output. So it makes sense that the earlier controller versions would be more powerful. This assumes that "C" is the latest model.