mmccabe,
Please check my math.
If the Solo/controller have a transmit power of 10 mW or 10 dBm( as I have heard) and the rubber duck antenna has a gain of 2 dBi we get an EIRP of 12 dBm.
I think the U.S. 2.4 gHz ISM EIRP limit is 36 dBm, EU limit of 20 dBm.
That gives an actual to limit...