[Cougar429]

You want that ferrite ring to be as close to the receiver on the lead as possible. It is used to reduce or cancel RF noise generated elsewhere from reaching the receiver and causing problems.

If too far away the amount of wire between the ring and receiver can act like an antenna and pick up noise again.

As for a separate power source that idea is used for larger machines such as my TREX600. The reason is with high currents going to the power system the noise generated by the ESC would be difficult to control, (you will notice higher powered ESC's do not have an onboard BEC for just this reason).

In the long run the only other reason for a separate flight system power source is to avoid any real high current drain on the main pack from "Browning Out" and possible loss of power to the flight control system. If you are running a 60A ESC you should really only be drawing a max of 45A for reliability. Most higher "C" rated batteries can handle this easily and a simple flight control system, (servos and receiver) should draw less than 5-10A max.

A separate battery for the flight control system adds weight and if you use a 2S LiPo or LiFE there are two considerations. First is that direct connection from the battery can supply in excess of 7V. Unless ALL of your components are capable of running that higher voltage, and new HV servos and receivers are, you will need to use a regulator to drop the voltage to 5-6V. BEC's or regulators are Power Limited, meaning you need to ensure either can provide the current required for your flight system needs. I mention this since a lot of the lower price units are set for a max of 3-6A output.

NOTE: As with any ESC, the BEC output rating is dependent on a flow of cooling air. If residing in a location of stagnant air then their output is severely compromised.

The second consideration is all of this adds weight. With the larger machines this is a smaller fraction of total aircraft weight, but with smaller machines, and including helis that use every bit of power for lift, then a BEC tied to the main pack would be the simplest and lightest option. Some very good systems are available now that can provide 10-20A continuously and weigh next to nothing.

If I may ask, what aircraft are you planning to install the system in? Perhaps someone has come up with a setup that works reliably.