Friday, 4 January 2008

2.4 GHz is totally secure. Or is it?

There are be thousands of modellers who entrust their models to 2.4 GHz radios, in the belief that 2.4 GHz spread spectrum transmission is inherently more secure than narrowband FM. And ignoring issues of external interference, hotspots, trees, water etc. 2.4 GHz is indeed much more secure than 35 MHz, because two spread spectrum transmitters simply cannot interfere with each.
...or can they?

A guy in my club claims that at another club he's a member of, two 2.4 GHz transmitters interfered with each other, leading to a crash. On further examination, the two transmitters were able to control the same receiver. Both transmitters were the same brand and type.

Now the only way this could happen, is they if the affected transmitters all left the factory with the same GUID. Since generating and loading GUID's is ultimately a human-managed task, we have to consider that this scenario is not as unlikely as it may at first appear.

If correct, this would be a pretty serious matter. Unless the offending transmitters could be identified by their serial numbers, the only totally option left to the distributor would be a total recall of all such sets sold. Otherwise, the manufacturers claims of interference immunity could not be guaranteed, and the purchaser would almost certainly have recourse under the law for a replacement set anyway.

Watch this space.

2 comments:

Peter said...

http://www.modelaircraft.org/news/radioservice.aspx

Mike said...

Thanks Peter. This one is going to run for a while.