How come a prime number of channels are required in the J-K Spread Spectrum Radios?


28 September 2021

The J and K series radios have the ability to lock out channels that might be susceptible to regular interference from other devices. If I want to remove a channel from the hopping pattern, how come I'm forced to remove more than one.


The hopping pattern algorithm is an advanced random number generation algorithm, that mathematically ensures a low probability of collision between multiple Trio systems, on different hopping patterns. Key to this low probability is hopping over a prime number of channels, hence you can only lock out certain numbers of channels to stay with a prime number. (i.e. 67, 61, 59, 53, etc...) There is also a certain minimum number of channels you need to hop over to remain compliant with various regulators like the FCC.

For radios approved for ACMA (915 to 928MHz), Trio radios start off with hopping on 31 channels. In order to maintain a minimum level of required channels, the ACMA radios can only be reduced to 29 or 23 channels.