11 July, 2023

A Much-Needed Power Supply Upgrade - MFJ-4128 MightyLite - KB3KAI

So I have been running my radio on a SLA battery with a 4A charger. Unfortunately the charger was introducing AC buzz noise into my transmit signal; guess I shouldn’t be surprised. I have a few small power supplies but they’re only good for a few amps at best. The bigger radio needs bigger power!

After much shopping and indecision I finally decided to buy an MFJ-4128 “MightyLite” switching power supply, good for 25A continuous / 28A peak power. Got it for a good price on eBay, new in the box. It has a few power hookup options including 28A banana jacks on the front (I would have preferred PowerPoles), 7A “lighter socket” on the front and 7A spring terminals on the back (not shown in the product photo below).

The new power supply is working flawlessly. A radio check on the Harford County repeater reports no more buzz noise in my radio transmission! Hopefully my power problem is now solved.