Cal Orr .com


Kraft 2.4 module built around JR DMSS 2.4 module


The Kraft 2.4 transmitter module is housed in a Kraft Channel Master case and will operate with a 7C or Signature Series transmitter.
Inside the Channel Master case is the 2.4 DMSS module itself, the interface electronics, 2.4 antenna, LED (front, to the right of 2.4 label) and bind button (back).

The output of this Tx module is DMSS only and requires the use of a JR DMSS receiver. Some features of DMSS such as telemetry and some features of the XBus can not be used with a Kraft transmitter.

The encoder output of your Kraft transmitter needs to be checked and adjusted. The output MUST limit the servo pulses to 1-2ms and the frame rate to 18-21ms. These limits MUST also include trims, preset buttons and mixing features found on some Kraft transmitters. To stay within these limits, it may also be necessary to change resistors on the Kraft encoder board.

If you don't know what I am talking about, send me your Kraft transmitter and I will make these adjustments for you.

I also recommend that you swap channels 1 & 3 (elevator, throttle) on your transmitter. Throttle should be channel #1 which allows you to take advantage of JR's fail safe. You may still plug in 72 mHz or Ham modules into your transmitter. In these airplanes you will have to swap the elevator and throttle servos at the receiver.

Note; many ESC's have a fail safe built into them - low throttle in the event of a problem. These ESC's will not recognize a hold as that is also a good set of servo pulses.

When using the Kraft 2.4 Tx module in your 7C or Signature Series transmitter, you will note that the RF meter on the transmitter is indicating some value. The meter will operate but it does not indicate anything except there is power to the module. The RF meter may have different readings depending on battery voltage etc. As long as the RF needle moved, aprox mid scale or so -  its ok.
The battery voltage meter on the transmitter has not been changed and will work as always. This meter should be between 9.6 and 11.4 volts for flight.

Do Not:
Do not use Li batteries or batteries that are higher than 11.4 volts for the transmitter or 2.4 module.
Do not use the Kraft “Buddy Box” feature with the 2.4 module installed.
Do not use the 2.4 module without its 2.4 antenna.
Do not use this circuit with a 5C or 3C transmitter.
The telescoping metal antenna should be removed from the transmitter when using 2.4.


*The telescoping metal antenna should be removed from the Kraft transmitter OR at least collapsed inside the case. An extended metal antenna close to the 2.4 antenna will kill your range.
*With the Kraft Tx off, plug in the 2.4 module.
*You need to adjust the 2.4 antenna so it does not point at the model when flying. You may rotate left /right but not more than 45 degrees as you might twist up the antenna wire inside. You may also bend the antenna away from the pilot but be careful in this position when laying the transmitter on its back,
*Power on - The blue LED will light. (The LED is seen on the front of the module, just to the right of the 2.4 label.)

The bind button on the back of the TX module has two functions.
#1 - If pushed and held when the transmitter is on, the RF output is significantly reduced. Use this feature as a range test. You need to get 30 paces (90') from your model. When the button is released the RF output is restored.

Note; The blue LED will blink in the range test mode.
#2 - Used to bind Tx to Rx.

Bind - Tx to Rx
#1 - Plug bind jumper into bind port of Rx.
#2 - Power on Rx, LED(s) in Rx (and satellite receivers) will flash fast.
#3 - Set sticks (and switches) on Tx to desired fail safe. Neutral and LOW Throttle, trims too.
#4 - Push and hold bind button on the back of the Tx module and then turn on Tx. Note, your Tx should NOT be right on top of the receiver. Move away a few feet.
#5 - In a few seconds the flashing LED in the Rx (and satellite receivers) will be solid and everything will operate. Release bind button.
#6 - Turn Rx and Tx off.
#7 - Unplug bind plug from Rx.

Turn on Tx  first, blue LED will light.

Turn on Rx, it will link in a few seconds with its LED(s) on solid.

*The Rx servo outputs are:
#1, Throttle       #2, Aileron       #3, Elevator       #4, Rudder
#5, Landing gear (Sig radios swap ch 5 & 7, Ldg is ch 7 on Sig)       #6, Aux 1       #7, Aux 2 (Ldg on Sig)
 * All the servos will have a slightly different neutral position with the 2.4 module as compared to the stock (72 Mhz) Kraft system.
* If flying electric, the Kraft throttle servo reversing switch needs to be “reverse” for most ESC’s.
* The Rx antennas (or satellite receivers) should be as far apart as possible and on different planes, one vertical and one horizontal.
* Several servos can cause voltage dips and cause a brown out with your JR receiver. You may want to consider 5 cell 6 volt Rx batteries or if you are flying electric use a BEC of 5.5 volts.

Any Questions - Please ask.