Notes on Frequency

Since I'm interested in doing RC + FPV + UAV functionality I'll have to pay attention to what frequencies I'm doing things on and what is legal.  I'm going to briefly mention some basics and then share some advice that I've been given and finally lay out what I hope my final system will be.

• The higher the frequency the more data you can transmit.
• The lower the frequency the more range you get.
• The higher wattage on the transmitter the more range you get.
• Frequencies can interfere with one another.
• Antennas are very important.  Maybe the most important part.

The most common out of the box frequency for flying RC vehicles seems to be 2.4Ghz.  The controller I purchased has this module installed, but it is interchangeable, so I will likely swap it out later.  Out of the box I was told it would give me about 500' with the stock whip antenna.  433 Mhz is a popular bandwith for long-range systems and I plan on purchasing that range system, but you have to get your amateur radio license from the FCC before you can use it legally!  Know your laws!!!

Unfortunately 2.4Ghz also seems to be a popular frequency for FPV.  5.8 Ghz is also popular.  1.2 and 1.3 Ghz frequencies are less popular.  For short range any of these are fine, but if you are going to start playing around with longer range you would either need to really up the power on the 2.4 and 5.8 Ghz frequencies, and high power transmitters can get really hot and can cause interference.  Obviously with 2.4Ghz it would interefere quite a bit with your RC control.  Not what you want, so avoid that frequency.

For UAV functionality most people want telemetry data and most people use a 915 Mhz system for that (check out DIY Drones 3DR telemetry module).  This one seems to be the creme-de-la-creme, so it's the one I'll use in the future.

Given all that here is what I am going with (at least in my head).

RC Control:  Initially I'll use 2.4 Ghz, but will later switch to 433 Mhz.
FPV: 1.3 Ghz at 300mW transmitter.  Can be upgraded later if more power is needed.
Telemetry: 915 Mhz at 100mW.  Telemetry data can be overlain with FPV so no need for a high power or high bandwidth system.

Antennas are the secret sauce.  They can make a high-frequency, low-power system outperform guys that are trying to push at over 1000mW.  The wrong antenna setups will severely limit your range.  I'm still researching what antenna systems to and will make new posts as I learn more.  Once I decide on a FPV system I will make posts on that as well.