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Your Reviewer

My Credentials
So who's doing this reviewing then?

Well I've been building and flying or driving radio controlled models for over 40 years and during that time I like to think I've built up a reasonable amount of knowledge.

I'm also a qualified electronics engineer who has worked in radio frequency, analog, digital systems and software for more than three decades. In fact I designed and built my first RC set back in 1969.

For the past nine years I've also been involved in the design and manufacture of some rather sophisticated engine technology and UAV flight control systems.

So, chances are I've been there, done that and have a huge pile of tee shirts to prove it.

Right now I'm heavily into 3D flying and enjoy all aspects of the RC hobby. I may be old but I don't feel it.

In the Pipeline

Here's just a little bit of what's to come on this site...

RC explained: Demystifying terms such as PCM, PPM dual conversion, single conversion, full-range etc., this feature will explain it all.

Cheap Chinese Engines: Just how good are those cheap Chinese glow and gas engines that sell for half the price of their "brand-name" equivalent? I put several to the test.

Build your own radio gear?: Back in the old days, building your own RC gear was not uncommon and now the arrival of 2.4GHz has made it practical again.


Encryption, a new "feature" for 2.4GHz?


Dated: 27 Mar 2010

The clones are coming...

Well the DSM2 and FASST "compatible" receivers are about to start flooding out of China, upsetting the highly profitable operations of companies such as Spektrum, JR and Futaba.

So what can be done by these manufacturers to thwart those who would simply reverse-engineer their protocols and build compatible products that sell for a fraction the price of the real-thing?

Well I'm picking that, if they're really keen on protecting their profits, the "brand name" manufacturers will be looking very closely at adding a layer of encryption to their systems.

How will encryption help?

Right now, the servo position data being sent from an RC transmitter to the matching 2.4GHz receiver is simply a string of binary numbers, each number representing the position of an individual channel

Once anyone wanting to build a compatible receiver has created an RF circuit that can receive the signal from such a transmitter, it becomes a very trivial job to reconstitute these numbers back into pulses of an appropriate width to drive the servos.

The job of building a compatible receiver is made much easier in the case of products from Spektrum because they use a readily available "off the shelf" chip from Cypress to handle all that 2.4GHz stuff. Anyone can buy these chips and, with the aid of a relatively cheap logic analyzer, work out the format of the data that comes out once a signal is received.

The most economic and sensible way that a manufacturer can slow down those who try to reverse-engineer their products is to encrypt those numbers before they're transmitted and then decrypt them when they're received -- before they're converted to pulses and sent to the servos.

Thanks to the ready availability of quite powerful computing power, in the form of MCUs (microcontroller units), adding a layer of quite strong encryption becomes almost trivial -- a piece of software than any second-year computer science student could accomplish.

However, reverse-engineering the datastream created by such an encryption layer becomes a whole lot harder and, if the encryption key is long enough, impractical to even attempt.

It won't stop the cloners though

Unfortunately, even a layer of strong encryption won't stop the cloners completely.

Even though a mathematically strong encryption system will take a very long time to crack via brute-force, some Chinese manufacturers will no doubt have access to other techniques which will help them in their reverse-engineering task.

X-ray microscopes and other clever tricks can allow those with the skills, knowledge, equipment and patience to extract the software which is burnt into the MCUs and which does the encryption. This would allow the cloners to duplicate the decryption code used in the genuine product -- however, it would be an expensive option and would stop the "backyard" or "kitchen-table" cloners.

Given the small amount of time and money involved in adding encryption to the data and the amount of respite it might offer "brand name" manufacturers from the appearance of new "compatible" receivers, I'm pretty sure it's something being contemplated right now.

Who would have thought that DRM and copy-protection would eventually affect RC systems?

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The Blog

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Here's a blog that will keep you informed just what's going on behind the scenes at RC Model Reviews and also tells you a little more about myself.

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