Wireless can be something of a black art, and there are a dizzying array of standards and choices. Here are some simple guidelines to help you pick wisely:
- --We operate in four frequency ranges: 72Mhz (RC gear), 900 Mhz (video and telemetry), 1.3 Ghz (video) and 2.4 GHz (RC, video and telemetry), not including GPS, which is a passive receiver only.
- --It is a BAD IDEA to have transmitters and receivers in the same frequency range right next to each other, so you'll want to choose your equipment to avoid this.
- --In general, the lower the frequency the longer the range because it can go around obstructions better, so 900 Mhz video tends to have longer range than 2.4Ghz video. But digital transmission technology can more than compensate for that, so it's not a hard-and-fast rule. For instance, a high-end spread-spectrum 2.4GHz wireless video setup can outperform a lower-end 900 Mhz one.
- --Some frequency ranges are more crowded than others. For instance, indoors and in urban environments 2.4GHz has to compete with everything from WiFi to Bluetooth to cordless phones. 900Mhz just competes with some cordless phones.
So, for example, you could try these configurations:
Configuration One: RC: 2.4Ghz. Xbee 900Mhz. Video: 1.3 Ghz
Configuration Two: RC 2.4 Ghz, Xbee 900Mhz, Video 2.4Ghz, with antenna as far from RC as possible
Configuration Three: RC: 72 Mhz, Xbee 900Mhz, Video 2.4 Ghz.
Comments
thanks Chris.
japi: sorry, typo. Fixed.
Hmm, why do I see no difference in Configuration one and Configuration three. So to use Video 1.3GHz do we have to have HAM licence?
I'm just beginning my reading on ArduPilot and everything that it entails... I'm completely impressed and plan to buy the necessary bits once I have money available.
In the meantime, my reading has lead me to the value of telemetry, in this case for the purpose of using ArduTracker (FPV antenna tracker). Near as I can tell, there isn't an xbee (or equivalent) transmission system available at frequencies other than 2.4ghz and 900mhz... both of which are in use on my rig (RC and FPV respectively).
1: Is there a 5.8ghz telemetry-compatible system available?
2: Is there any chance of a telemetry system being cheaper than $150? That price is killing me :(
This is the sad truth about most RC electronics. They're just the simplest cheapest parts repackaged & marked way up because most people in RC don't know a thing about designing circuits.
The XBee PRO is probably as good as any $300 radio set. You can build a triple redundant full duplex XBee PRO link for less than a $pektrum.