MTK 446 electronic timer: RCDT radio override

Introduction

The Radio Command Dethermalisation (RCDT) system allows the timer FLIGHT program's d/t setting to be overridden by causing an immediate d/t or extending the flight time. It is an optional extra feature for the MTK electronic timer and consists of a transmitter, receiver and cable for connection to the timer. The easy-off receiver can be installed outside the fuselage for quick removal before an official flight. The transmitted signal is coded to avoid interference from other flyers using RCDT systems.

NOTE: this facility is only available if you are using the 2004 timer model.

Standard features

• plug 'n play add-on for the MTK electronic timer
• provides "immediate d/t" and "glide extension" functions
• operates on 400 MHz
• maximum range is about 700 m on the ground
• 100 field configurable codes
• transmitter size 90 x 57 x 24 mm, weight about 120 g
• easy-off receiver size 20 x 13 x 5 mm, weight 3 g
• power supply for the transmitter is a standard 9V alkaline battery

RCDT components

System requirements

• receiver
• transmitter
• interconnect cable between receiver and electronic timer
• MTK electronic timer, Palm or Casio programmer and standard programming interface cable

All system requirements can be supplied by M&K.

Preparation for use

1. Install the receiver cable in the model
2. Plug the receiver into the socket on the end of the cable. The GROUND pin of the receiver must connect with GROUND wire of the cable (the black wire). ATTENTION - the wrong connection may damage the receiver!
3. Program the transmitter with the SETUP program from one of the models it will be used with. The procedure is:
   • connect the transmitter to the Palm or Casio by interface cable. Push the jack into the transmitter until you feel resistance; there should still be about 1 mm of the barrel showing. If you push the jack fully home the Palm will report "no connection" when you try to program the transmitter
   • switch on transmitter, wait about 1 second for READY mode (the transmitter beeps twice every 2 seconds)
   • send the SETUP program to the transmitter. During transmission the transmitter will buzz continuously. When download is complete the Palm or Casio will display a caption box showing that the program has been loaded successfully and the transmitter will stop beeping
   • switch off the transmitter
   • disconnect the cable
4. The system is now ready to use.

The SETUP program is the same as that used to configure the MTK timer to match the servos and altimeter. Because only one transmitter is used with all your models you should put the same RCDT code in the SETUP program for every model. The code is a two digit numeric value in the range 00 to 99.

This allows you to choose among 100 RCDT code values. If you find that you are using the same code value as another flyer at a contest, you can change the code in your transmitter and timers on the field. If you do this, make sure you change all your models to the same code and that you load the correct SETUP program into each model.

The transmitter stores the RCDT code in non-volatile flash memory so it will not need reprogramming unless you change your RCDT code.

Using RCDT

You can use the immediate d/t function when the model is on tow or gliding and the glide extension function when the model is gliding. Switch on the transmitter, wait about 1 second until you hear the READY mode beeps, pull out the antenna then push either the DT or the Extension button. Transmission time is about 3 sec. and accompanied by rapid beeps.

NOTE: don't squeeze the face of the transmitter hard when it is switched on because, due to the very small space inside, this can cause it to transmit a command to the model without any buttons being pushed.

Changing the transmitter battery

• switch off the transmitter
• remove the front cover retaining screw
• open the front cover
• change the battery
• replace the front cover
• replace and tighten the retaining screw