Forum Post: CC2511 RF Issue

I’m seeing some weird behavior with the CC2511 when operating on certain channels. When you select a carrier frequency that is close to either the 50^th or 51^st harmonic of the 48MHz crystal, I get the spectrum I can send it to you.

 For example, I selected a carrier of 2400.5MHz. When I do this the 50^th harmonic of the 48Mhz crystal appears, as well as the intermodulation spur at 2399.5MHz appears. As I increase the carrier frequency from 2400.5MHz to 2402MHz, the 48MHz 50^th harmonic reduces in amplitude and until it is gone at 2402MHz. The problem is that the intermodulation spur at 2399.5MHz is outside of the allowable band.

 This happens both on my own board and the TI demo board. Any help with this would be appreciated.

Thanks,

John