Wednesday, 19 January 2011

Telemetry with M-LINK, and some thoughts on the Spektrum DX8

Today I had my first taste of Multiplex's telemetry system in action. I flew my Easy Glider electric with two sensors: the 35 Amp current sensor, and Altimeter/vario. Controlling this lot was a Multiplex Royal Pro 12 M-LINK transmitter and RX-7-DR M-LINK receiver.

So how did it go? As the there is a review pending in RCMW sadly my lips must remain sealed; suffice to say, I was smiling when I left the field.

While I was there a chap came along with a T-REX 600 equipped with a Spektrum DX8 and a temperature sensor. Now, Spektrum describe their telemetry system as 'integrated', but this is only half true. While  the DX8 transmitter is telemetry-capable (you can view the telemetry data on the screen), the AR8000 receiver cannot do the downlink - you have to install an additional downlink module (TM1000) in the plane. Compared with the M-LINK telemetry, Spektrum's solution looks distinctly klunky.

Screen placement is important for telemetry. The DX8's screen is located near the bottom of the case, a drawback shared by most Asian sets as they compete to see who can provide the biggest screen. Unfortunately this is just about the worst location possible for displaying anything at all, let alone telemetry data. Neither was the screen particularly easy to read.

I'm sure that the DX8 is a fine system, but radios need to be designed with telemetry-friendly ergonomics if the benefits are to be truly realised.

Telemetry is an exciting development, with the potential for safer and more enjoyable flying. The challenge for the manufacturers is to work out cool ways of using it, of programming the sensors and of presenting the data to the user.

Telemetry a la Multiplex. Note the very clear screen.  Easy Glider in the background, with 35A current sensor just visible. On the transmitter screen, line 3 shows instantaneous current (almost zero as the motor is switched off), line 4  is peak current from the previous flight, and line 5 is mAh remaining in the flight battery. The last line is highlighted because it triggered an alarm. A total of 15 data lines can be monitored simply by plugging in extra sensors.

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