ORIGINAL: beau0090_99
Baracuda,
You are right that it is spread across a wide spectrum, but in fact some systems only use a few of the channels when in use, and this can be a problem. If you power up your Tx and it chooses two channels in the 2.4 spectrum that are near to each other, and then during flight someone powers up a strong 2.4 system (like for Video broadcast, FPV or something like that), and is sitting over your channels, it may overpower your signal and cause a glitch or crash. If the system frequency hops, then the liklihood of this is decreased.
That is not quite an accurate view.... and it reflects the old 72mhz "channel" thinking.
In DSM/DSS the "channels" represent a range of frequencies, unlike 72mhz which is centered around a specific frequency.
Even if one frequency is blocked, adjacent bandwidth is available for the DIGITAL transmission and reception.
Only a very wide broadband signal has any hope of blanketing this 2.4gHz "channel", and that is relatively difficult to do.
As a safeguard there is the secondary frequency range also available.
If you start throwing other signals on one range, the receiver simply does not pay attention to them because of the encyption.
The link you posted also goes into this...
Frequency hopping works well if both the TX and RX are in sync with each other. I'm not familiar how Futaba's tech deal with the RX determining the next frequency though. I don't know if the TX tells the RX before the "hop" where to go to next.
I'd imagine there would be a delay in reaquisition if the target frequency is in use, but since our equipement functions so quickly now, it would be impossible to notice.