I'm working on a quadcopter and have some questions about the receiver and transmitter. I'm going to be milling the boards myself and wanted to know what would be a good carrier frequency to use. I was planning on 10 MHz but I'm not sure if it's better to go higher or lower? I also have the basic block diagram laid out and was hoping if someone could give it a once over and let me know if I'm missing anything. For the modulator block I was going to use the SA605 chip.
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1\$\begingroup\$ Which frequencies do you have licenses to use in this way? \$\endgroup\$– W5VOCommented Sep 15, 2018 at 22:41
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\$\begingroup\$ The user profile country / location is there to help in cases like this where local legislation will affect the answer. You should add in your details. \$\endgroup\$– TransistorCommented Sep 15, 2018 at 22:47
1 Answer
It's better to go with something that you're allowed to use. That depends on your region. A shortlist follows (source):
- USA/Canada: 72 or 2400MHz.
- Europe: 27, 35, 40 or 2400MHz.
- UK: 459MHz.
- Singapore: 72 or 2400MHz.
- China: 1400, 2400 or 5800MHz.
- Australia: 27, 29, 36 or 2400MHz.
- New Zealand: 27, 29, 35, 36, 40, 72 or 2400MHz.
Even within these bands there are often restrictions, so best to check. You also want to make sure you're doing something to both tolerate interference and not cause undue interference.
After all that is said and done, then you can worry about which is better. Roughly speaking, lower frequencies carry further but need a bigger antenna. Higher frequencies attenuate more but can have a higher data rate. You have to make a trade-off.