Originally Posted by DavidR8
Last week I pulled the wing off my Fun Cub for the first time. I both this plane fully built and know it flies well because a local club flier told me the maiden flight (and it's only flight) was perfect.
One thing I noticed is that the servo connections are run through and around a circular magnet about 3/4" in diameter.
I recall this is done to reduce electrical RF 'noise' (I think) but have never seen it mentioned in any build forum.
I'll post some pics later today but I'm curious about initial thoughts.
Those were used to reduce electrical noise from the ESC from getting into the 72 Mhz receivers. Especially if you're running brush type motors on more than 20 Nih cells.
Back in the late 1990's, I had an Astroflight Geared 90 brush type motor that was running on 38 sub C Nicad cells. Radio interference was so bad, I only had about 10 feet of radio range. With the transmitter antenna fully extended.
Finally reduced the radio interference to tolerable levels by running the motor leads through a pair of those ferrite chokes, one for each motor lead.
Nowdays, it is not easy to generate 2.4 Ghz (That's 2400 Megahertz) unless you've got specialized chips to do the job. You're not going to generate 2.4 Ghz interference from things like motors, or ESC's.
I did see one of those ferrite chokes on the leads of a Common Sense uBEC awhile back. Mostly to eliminate the 72 Mhz radio noise from the uBEC's switching regulator. The Castle Creations uBEC's don't use them. But for me, on 72 Mhz, I'd install one of those ferrite chokes on any 72 Mhz receivers with the CC uBECs. Just in case. (I've measured a fair amount of radio noise on the CC uBEC's battery power leads.)