Spektrum Hack Module

I recently put together a Spektrum hack module for my Taranis. These are my notes from that process. If you want more info on what exactly this is, or more technical details on the PCB, this blog post contains the relevant information.

What you need:

• RF module from a Spektrum DX4e, DX5e, or DX6i
• PCB - I got mine from Radiocontronics. The blog post linked above provides details on making your own if you're interested in going this route.
• Case - Horizon Hobby sells a replacement DM9 case that works perfectly. If you have a 3D printer, this is another option.

Getting an RF Module

Since Spektrum doesn't sell RF modules by themselves, you'll have to harvest one from a donor radio. The DX4e, DX5e, and DX6i will all work and give you 6 usable channels. If you don't already have a donor radio, you can check ebay or the classifieds section on RCGroups.

Note that the older SKUs of these radios only supported DSM2. If you're buying a radio specifically for this purpose, I'd highly recommend spending a little extra to get one that does DSMX.

After you remove the RF module, the radio can still be used as a buddy box. If it's in good shape, you may also be able to sell it for parts afterwards in order to recoup some of your money. That's what I did with the DX6i that I used.

Removing the RF Module

Remove the screws on the back of the radio and separate the halves. There will be some wires running between the two halves. Unplug them and and set the back half aside.

If you're not sure where the RF module is, simply follow the cable down from the antenna. On the DX6i the module is socketed. I haven't personally seen inside a DX4e or DX5e, but from what I understand it's soldered to the board, so plan accordingly.

Inside the DX6i

Installing the RF Module in the PCB

The PCB that I got from Radiocontronics has a socket installed. If you opt to build your own PCB, you'll have the option to install a socket or simply solder the module directly to the board.

The PCB from Radiocontronics also comes with standoffs. They work great, but I had to to shorten the pins on my DX6i RF module 2-3mm in order to get them to snap in correctly. I believe that this step isn't necessary with the RF modules from DX4e or DX5e.

Shortening the pins on the DX6i RF module

Putting Everything Together

With the PCB and RF module mated, It's time to install it in the case. First set the PCB into the case and make sure that it fits correctly and that all the mounting holes are free of obstruction.

PCB in the case

If you're using a DM9 case, there will be a button in the package that is meant to be used with the DM9 board and won't fit with this PCB. You can simply leave this out, but in order to prevent dust from getting in the case I affixed mine in place with a drop of thin CA and trimmed off the excess.

Once you've confirmed that everything fits correctly, plug in the antenna and assemble the case.

Setting up the Transmitter

Install the module in the bay of your Taranis and set up a model. Set the Internal RF to off and External RF to DSM2 DSMX.

Taranis with hack module installed

RF module settings

Once that's done, bind the receiver as you normally would. I also found that it was necessary to reverse the aileron and rudder channels.

Final Thoughts

I'm extremely happy with how the module came out. I've used it successfully with a UMX Pitts and a Blade Inductrix. It's nice being able to fly my Bind-N-Fly stuff without needing to bring along a second radio.

At the time of this writing, you can expect to spend roughly $70-$100 to put one of these together. The cost would obviously be significantly less if you already have a donor radio. If you want one of these modules, I'd recommend doing it sooner rather than later because the supply of donor radios will inevitably dry up at some point.