Hi Mike,
The SA44 and SA124 only have an analysis bandwidth of 250kHz which limits you to symbol rates of ~150kS/s or less (most signals). Our software sets the device bandwidth to 2*samplerate when looking at a signal. This does limit you to certain signals for the SA44/SA124. Our BB60C spectrum analyzer has an analysis bandwidth of 27MHz, and is much better suited for wideband signal measurements.
I hope this helps.
Regards,
A.J.