3DR 915MHz Air Module Versions

I recently dropped a line to the DIYDrones store folks when I noticed that images posted for the 915Mhz Air module in the store are different to the ones in the documentation and also picture shown of this module in the 3DR Telemetry kit.  I am mainly interested if there was an change in the design / version release of the hardware and would like to know what is shipping currently?  In other words is there an updated air module to correct some problem?  Below are the comparative images. You can clearly see the main board in one version is purple and the other is green.  What is clearly evident is the orientation of the HM-TRP module.  For the all green circuit board design (photo shown in the store for the 915 Air module on its own) the HM-TRP module connector is parallel to the main board edge connector (FTDI-style pinout).  In all the other photos of the Air module (included in the kit photo and manual)  the HM-TRP module is oriented 90 degrees to the FTDI-style pinout.  

I can make out v1.2 on the all green board.  But cannot see the version on the purple main board version with  HM-TRP module on top and at 90 degrees to the FTDI-style pinout.

I just want to understand why there appears to be two different versions of the 915MHz airmodule? Does anyone know? When I tried to get a sensible answer from the store contact they thought I was referring to the air and ground module.



Note the differences between the HM-TRP component orientations in the above two images of the same item (3DR Radio Telemetry 915MHz Air Module).

Has anyone recently received their 3DR radio kit and can confirm what version of the air module they have.  I have not picked up on any other forum discussion on this.  Somewhat of a mystery to be solved.


You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


  • Are the 900 radio sets every going to be in stock? I have been waiting for a very VERY long time but it always gives me that goofy WHOOPS!  message.

    They should at least open it up to per-orders so I can get one when they are back in stock.




  • Any news on 915 MHz availability? It’s need quite a while since I have seen any news. Any estimates on when it will be available?

  • Today I received my 3DR 915MHz Radio Telemetry kits, but both appear to have build quality issues.  I firstly want to point out the diydrones folks do a fantastic job in providing these products and I am sure I can fix the problems, so I don't want this to be taken the wrong way.  Below is a photo of one of the ground modules I received and the main problem is the soldering or lack there of in places.  In the photo below you can see solder missing on some of the pads (near the usb connector) and there is excessive flux and overheating signs on the antenna connector.  I compared this to the store photos and there are no signs of this issue. One of my main concerns is the HM-TRP module which on all 4 boards is not lined up with the main board pins and there is virtually no sign of soldering filets between the upper and lower board in some places.  So I am concerned about reliability, with a little in flight vibration over time.

    In this post I had asked about the two different board designs and it would appear there are build quality issues with the later model (green board) modules.   I will have to re-solder all the modules to fix the issues.  The tricky bit will be the HM-TRPmodule. Perhaps it would have been better to take more time building the purple style boards versus using a fast build process for the new version and different HM-TRP module orientation?


    A few other issues I noted include the right angled pin edge connector which is supplied with the Air Module.  Instead of the gold plated pins shown in the 3DR Radio Telemetry documentation a tin plated alternative is supplied.  I will need to go out and buy a suitable replacement.  Again no big deal but annoying not getting the quality expected.

    Finally could someone comment on the current telemetry antennas supplied.  They store notes say they will swivel but the four I received are all fixed and I dare not try an turn the screw base for fear of braking the internal antenna wire.  So for now when I screw on the antenna I am stuck where the antenna points as it appears it cannot be turned?  

    So a few issues for the suppliers to sort out.  Hopefully I can re-solder the boards to fix the issues.

    Another quick question.  Does anyone have photos or notes on how they mounted the 3DR telemetry radio on the arducopter?  The air module is tiny and unlike the xbee pro does not have any way to nylon screw fix the circuit board to the frame.  Also because the surface mount components are so delicate I would not risk using tie traps. I thought of using a piece of double sided tape but worry the sheer weight of the antenna, when the arducopter is flying and accelerating, might break off the antenna connector or lift the board off.

    Its worth noting the ground module version I received in both kits is version 1.0 and the air module is marked v1.2  I assume this is related to the air module design change and the ground module remained the same?  I certainly hope there is no version mismatch.

  • Greg, the green board is a revision of the first 'air' module, our shop is better suited for SMD assembly and the first boards were a bit time-consuming to make. Both versions of the air module work exactly the same way.


  • Just another quick question.  Has anyone connected the 3DR Radio Telemetry air module to the APM1 board.  The wiki talks about connecting the APM2.   I am hoping this product is supported on both APM1 and APM2.  I don't see any issue since both have a similar telemetry port specs, but thought it better to ask just to be safe.

  • Hai Tridge,

    can this 3DR telemetry kit replace my xbee pro 900 which i usually use with my Mikrokopter Hexa? Perfomance?


  • Developer

    Hi Greg,

    It's just a manufacturing process change - the performance of the two is the same the tests I've done. Sam would be able to give more details, but as I understand it the new layout makes better use of the machines that 3DR have invested in.

    I've had both types for a while, and haven't found any behavioural or RF differences.

    Cheers, Tridge

  • I recalled a comment by someone (Jake?) that the original layout (top picture with purple board) was not optimal for RF leaving the board. Maybe this is a fix?

    I could have dreamt all that though........

  • My air module is like the picture at the top - purple breakout board, daughterboard is rotated 90 degrees and soldered on using a pin header.

    My ground module has a similar orientation to the bottom picture - green breakout board, daughterboard in line with the breakout board.

This reply was deleted.