My Trimble dealer is switching the base tower I use from 900mhz to 450mhz. If I want continue to base I would have to  change the radios in all my FMX's. Complication the switch is I have a 900 base station that I own the a use with field level to survey rice levees.  What are the pro and cons of switching to RTX and continuing to use my 900mhz base for survey as oppose to updating the fmx displays and  my base 450mzh? How would the cost compare? Currently I have no modems to use RTX.