I have the RF T4 receiver connected to an arduino which controls a servo motor. Why is it that everything works as long as the arduino, which is powering the RF receiver, and the servo are connected to separate power supplies? Once I try to connect the arduino, the RF Receiver, and the servo to the same power supply the Reciever begins to not work properly. The servo behaves erratically and the RF Receiver will no longer work? Is there a way to run everything off one power supply and still have everything work properly? I am only using one tiny micro servo with no load on it so power is not an issue. There seems to be some sort of interference going on with the servo motor and the RF Receiver. I have tested it with serval different brand servos. All do the same thing. Please help.
Generally, the arduino can't supply enough current to power a servo - rule of thumb is to budget an amp. With a micro servo & no load, you might get away with it, but in your case it appears not - how much does the radio draw?
As far as the radio amp draw rate I'm not really sure. I know it uses 5 Volts. However I have even connected the arduino to the 6 volt supply battery and then ran separate leads from the same 6 volt supply to power the servo. When this is done the RF Receiver doesn't work. Once I disconnect say the arduino from the 6 volt power supply and then plug the arduino into the USB power supply or a 9 volt power source, then everything works just fine. I just want to be able to power everything from one source instead of having two separate power supplies.
What you need is adequate power supply decoupling, which is a complex subject, and difficult to get right if a noisy motor is involved. The simplest solution is to use two power supplies.
If that is not satisfactory, google "power supply decoupling" for lots of leads.