Tandem TD MX tips and ideas

Small, light, inexpensive 2.4ghz/900mhz dual band receiver




The Tandem TD MX is FrSky's best kept secret.  It's small, weighs next to nothing and is a full dual-band 24 channel receiver, much like the TDR18.  Oh yes, the best part?  It's the least expensive TD receiver FrSky sells. 

The ideal solution for the TDMX is in conjunction with the RB series of Flight Safe redundancy systems. Here's a picture of the RB30+.  It has 24 output channels that match up to the TD MX's full output channels. Best part of all, you can have up to 3 TD MX receivers and use all of them.









To use the TD MX with the RB30+ you will need 4 wires.  Ground (Black), VIN-power (Red) S.Port (Silver) and SBUS Out (Yellow).   The S.Port is your telemetry and S.Bus out can go into RX 1 2 or 3 in on the RB 35+.   It can also go into Pin1 on a TDR-10 or TDR-18 (The TDR-6 only has S.Bus out, not in).  On the RB 30+ there is a spot for your S.Port in for each receiver.






Practical uses for a TD MX


One receiver system


The TD MX has redundancy built in with the dual band. Thus, if you're using an aftermarket gyro like an AR Smooth Flight   all you need is S.Bus out, power and ground.  Because of this, you can move the receiver away from the fuselage such as on a wing where things like battery packs, motors and turbine engines have less chance of blocking the signal.  


Two receiver system

Use a TDR 10 or TDR 18, change pin 1 to S.Bus in and take S.Bus out from the TD MX.  Though you really don't need a second receiver, this is cheap peace of mind.  Have your TDR 10 or 18 in the fuselage, move your TD MX out on a wing..


4 Channel Foamies

For not too much more money, you can have a TDR 6.  This is a good foamie receiver with most of  the benefits of the TD MX.  It has six PWM channels. If you're looking to move the receiver out onto a wing, on the tail, or somewhere out of the way, you probably don't want keep your redundant wiring to a minimum the TD MX is a better choice.

The TD MX has a 1-2-3-4 on it as well. These are the first four channels of a receiver. They are fine for 4 channel foamies such as flying wings, or simple plane setups with the first four channels on one channel (use a Y cable for ailerons).

The wiring needed for the TDMX doesn't need to draw much current.  Thus you can run simple 26 AWG silicone wires to the TD MX to help keep the weight down. Then bring 4 channels back with the same silicone wires.  This works well if you plan on putting the TD MX on a tail of your plane and you're looking to keep the weight down to avoid CG issues.

You can power your servos with high power SBEC such as the Nueron 8A SBEC. When you do this, you can monitor your current and voltage of your SBEC. With the use of the S.Port out on your SBEC you can bring it into your receiver and get telemetry from your SBEC.  This will help show you how much power your servos and system are consuming.    The output ranges from 5v to a full 8.4v for high power servos.





Extra Credit


If you wish to make your TDMX something you plug in the proper pin size is a JST PH 2.0mm connector.   There are 10 pins total, if you don't need the 4 channel outputs, a 5 pin connector is all you need.  (Thank you to to Rick Silz for your suggestion and photo).



















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