I'm new here, I hope this is the right place to post this.

I've been trying to setup a Pixhawk in my Talon and I'm just not getting it right.

Here's what I've got so far:

I've lifted up the Pixhawk and tried to spread everything out to make it easier to see, if someone could tell me if I've wired it correctly that would be great.

I'm using a FlySky FS-TH9X transmitter with a FrSky V8JT module:

I've got my Talon working without the Pixhawk but when I plug it in I get no response from my servo's or motor. I've updated the Pixhawk firmware and get the startup successful tone.

Here's the process I've gone through step-by-step with questions in between:

  • Place jumper over pin 3 and 4 of my Delta 8 receiver for CPPM output, as described in the Delta 8 manual http://www.valuehobby.com/media/wysiwyg/upload/Manual/Delta-8.pdf
  • Do I need CPPM for my Pixhawk setup?
  • Hold transmitter module button in (FrSky V8JT) and power on transmitter
  • Hold Delta 8 receiver button in and power on Talon
  • Delta 8 receiver LED: Green LED slow pulse (Indication: Linking to FrSky V8)
  • With the jumper over pin 3 and 4 I should be getting a solid red and fast pulse green LED on the Delta 8 receiver to indicate that it's linked in PPM output mode according to the manual
  • Unplug Talon battery
  • Switch off transmitter
  • Remove the jumper on the Delta 8 receiver
  • Switch on transmitter
  • Power on Talon
  • Solid green Led on delta 8 (Indication: Receiving signal)
  • According to the Delta 8 manual I should be getting solid red and solid green LED to indicate Receiving Signal + PPM Output. Which is what I need isn't it?
  • Pixhawk LED: Flashing red and blue (initializing), then startup successful tone and flashing yellow LED
  • Pixhawk safety switch LED blinking red (system ready), then I hold in the safety switch until I get a solid red LED
  • Pixhawk makes a long beep (about 2 seconds) which indicates that it's armed?
  • I'm lost from here, what do I do next?

If I connect my Pixhawk to my PC and run APM Planner (do I just connect it with a usb cable or must the battery be plugged in too?) and run the initial setup I get up to Radio Calibration where none of my sticks register anything.

Any help would be appreciated, thank you for any assistance in advance.

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Replies to This Discussion

Almost everything looks right to me.

I've never used the Delta-8, but on D4R-II, you need to leave the jumper on for it to actually be in PPM mode.

I recommend you connect and leave the jumper on your RX between pins 3 and 4, then proceed to the radio calibration step.

Hi Grant and Scott,

I have 3 Delta 8's and an Hitec Aurora 9 transmitter I am happily using it with.

I also have an oscilloscope and although I have 2 of the Delta 8's working fine on PX4's it wouldn't work on my Pixhawk.

Used scope to determine had a fine PPM-Sum (CPPM) signal coming from the receiver and in fact my Pixhawk wasn't seeing the PPM-Sum signal.

Bad Pixhawk, a new one is in the mail as we speak.

As to your specific experience.

First, after binding with the CPPM jumper in place you can (in fact I think have to remove the CPPM jumper).

I believe all the rest of the regular PWM channels operate simultaneously with the CPPM output so the jumper would be a problem.

Second, the LEDs on the Delta 8 are very hard to read and I have found their indications to not be at all as clear as the manual might make you think.

Among other things when the red and green LEDs are on simultaneously the green led is barely visible.

And the blink / steady relationship for my system was not exactly as claimed, but it actually bound and worked fine anyway.

Which PPM-Sum signal I was clearly able to see on my Digital storage oscilloscope.

The only other variable you might have is whether the FRSky module actually works with the Flysky transmitter (and the Delta8 receiver).

It would be of great help to you if you could get ahold of a digital storage oscilloscope and look at the expected PPM-Sum out signal line on the receiver to see whether you are actually bound and outputting PPM-Sum or not.

If you look at the PPM-Sum output on the Delta 8 with single shot you should show a long period square wave (5 ms) and 8 short ones which are the actual channels.

Sometimes an oscilloscope really helps make the invisible obvious.

Best Regards,


Hi Grant,

I should add, I am getting a solid red LED on and a solid green LED on (although the green LED is barely visible next to the super bright red LED) on the receiver when it is powered and the transmitter is also on.

You do need to have both the receiver red and green LEDs solid on while the transmitter is on to indicate a bound and in PPM-Sum mode state.

And is what you also need - if you haven't got that you are definitely not bound.



One thing I noticed for safety - you don't need to arm the Pixhawk to test/calibrate radio. All the RC inputs work normally while disarmed and obviously you don't want the prop to spin up when you calibrate throttle.

Regarding USB connection with Pixhawk you can connect this at the same time as battery (it may run without battery but USB might not supply enough power). I notice you have a telemetry radio though - all the calibration and set up can be done via telemetry if that saves you some time and cable fiddling.

Good luck!

Hi Gary

Thank you so much for your reply.

I'm going borrow an oscilloscope to test the PPM-Sum signal as soon as possible.

I have setup my Talon without the Pixhawk using my Flysky transmitter, FrSky module and Delta 8 receiver and everything binds and works so I don't think that's an issue. If my transmitter uses PPM it will be able to receive PPM-SUM right?

I'll have to check with the oscilloscope but in the meantime no matter what I do I don't get a solid red and solid green LED on my Delta 8 indicating that it's in PPM Output mode. I've looked very closely in case it's a weak red LED and I don't see anything. I guess it's possible that the red LED is broken. We'll see when I get hold of the oscilloscope.

Okay thanks, I'll remember that, I was just at a bit of a loss as to why my radio calibrations weren't picking up anything and thought maybe I need to arm it. My prop is off for safety :)

At the moment it's pretty easy to just plug a USB cable into my pixhawk, I'll use the telemetry unit once I've got this working and do a proper calibration.

Thanks for your advice :)

Hi Grant,

On all my Delta 8 receivers, the RED LED is very bright and the green LED is very weak which I think is just a matter of much higher lumens for the RED LED, so if you are not seeing the red LED it is probably because it is not coming on.

It sounds like you are binding fine in (regular 8 channel PWM mode), but not in  PPM-Sum mode.

And that is why I asked if you were sure that transmitter would work with that receiver in PPM-Sum mode.

Clearly it is OK in regular PWM mode but not in PPM-Sum.

I know they usually use a PPM-Sum capable FlySky receiver with that transmitter.

And that might be the easy option because since the RED LED isn't coming on solid it doesn't seem like you are able to get it to bind in PPM-Sum mode.

It does do on all 3 of mine.

Just this moment received my replacement Pixhawk which I will be hooking up today and I will get back to you with my results with Delta 8 on PPM-Sum/CPPM talking to Pixhawk today.

I will be hooking it up through USB only no battery and no outputs to test the Receiver operation.

Best Regards,


Hi again Grant,

Just to clarify, I just got my replacement Pixhawk and hooked it up with external GPS/Compass, Delta 8 receiver, arm button and buzzer.

It is not installed in my copter yet.

Delta 8 was already bound to my Hitec Aurora 9 radio and outputting PPM-Sum / CPPM signal.

When the Pixhawk is powered via USB but transmitter is not on, Delta 8 Green LED blinks.

When transmitter is powered on Delta 8 LED goes to red and green on solid although red led is much brighter than green.

It also now shows hooked up in Mission Planner radio calibrate and green bars move when sticks are moved.

If you are not getting green and red leds going to solid from green blinking on on the Delta 8 when the transmitter is turned on it sounds like you are not actually bound in PPM-Sum mode.

I did not use a battery connected to the Pixhawk at all in this verification process, but I have a new computer and it likely has a sufficient power supply on it's USB bus.

Best Regards,


Have now flown my quadcopter and Aurora 9 and Delta 8 are working fine.


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