When flying with a group of FPV drones, it’s important for each drone to be on a unique video channel. For that reason, the available spectrum has been divided up into several bands, with eight channels in each. The frequencies for those channels have been selected so as to allow for maximum space between channels, to minimise crosstalk and interference.
In Australia, the usable “ISM band” ranges from 5725 – 5866 MHz. Available channels on FPV devices sometimes lie outside of this band, so it’s important to ensure you only use channels within this permitted range.
It can be difficult to visualise the relationships between the channels and bands, and where they all sit within the spectrum.
It’s important for all pilots in the same area to be on the same band. Two pilots, with one on A1 and the other on B8 might think they are very far apart, but in fact the difference between the two channels is only 1MHz — which is insignificant. Their video signals will mix, making both unusable. This is a pain on the ground, but if one quad is flying and the other powers up, the flying quad’s signal will immediately be lost.
Even with individual channels, the signal can “bleed” into the adjacent channels within a band. Raceband was devised to allow as much “buffer” between channels as possible, but sadly this puts many of the Raceband channels outside of the legal Australian spectrum.
Interestingly, Band A is the only band where the channels run from high-to-low, and I don’t even know what’s going on with the bottom half of Band E, where up is down and down is up…? If local laws allow it, Band A and Band E could work really well together, with a 20MHz gap between each channel. Raceband and Band L are similarly well-matched (where it’s legal to use them!).
Over on the Rotor Riot facebook page, Kye MacDonald makes the argument that there is “zero reason why all pilots should be on the same band”. Kye suggests using a mix of the E and F bands for maximum channel spacing, and suggests that pilots should set the frequency directly without relying on the “band/channel” paradigm:
- E4 (5645)
- E2 (5685)
- F1 (5740)
- F4 (5800)
- F7 (5860)
- E6 (5905)
I disagree that there is “zero reason” to use the band system, because being on the same band keeps things very simple. His suggested band-splitting approach works, sure, but ends up being a slightly more complicated way to accomplish what Raceband set out to achieve, with the added admin overhead of splitting two bands and recombining into one. Essentially it’s a band system without the convenience. It might be worth a try if you’re flying with six people and getting a lot of cross-interference, and local law permits you to use those frequencies.
…Here’s how what I’m calling “KyeBand” looks, if you’re curious!