These are the ones I use.? They are nice to reassure you that the Pi and modem are getting the correct voltage.? You can check the supply voltage at the same time by pushing a button on the unit.? I have put about 25 of these in service over the last five years and have had no failures.? I connect the power out to a couple of the pins on the modem board GPIO and power the modem and Pi.? Do not connect a 5V source directly to the Pi when using this configuration.
<https://www.ebay.com/itm/DC-DC-LM2596-Power-Supply-Buck-Converter-Step-down-Module-LED-Display-Voltmeter/402421639705?hash=item5db232ea19:g:miQAAOSwHfpfWG6Y>
73 - Jim? W5ZIT
