no buck
-------
vsupply, 
3.6, rftest-rx 46mA
3.27, rftest-rx 42mA
3.03, rftest-rx, 39.5mA
2.56, rftest-rx 35mA
2.2, rftest-rx 32mA

buck
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3.58V, 39mA
3.3, 37mA
vsupply 3.03, rftest, 35.3mA
2.47, 32.9mA
2.2V, 31.2mA

might have a hard time starting up everything in the <2.7V range
