Installed the ancient XBee Pro 900's & got instantly perfect results.  These were the only true frequency hoppers that really work.  The connection time is still a very long 30 seconds & the power consumption is 100mA.  They could be reconfigured for lower power, but the 2.4Ghz ran at 100mA for 5 years.  The packet rate is only 25Hz. 

The ancient XBees are still the same outrageous price as 10 years ago.