Re: Noisy Pi4 - particularly on 2m
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There are lots of these modules around, some are better than others. I have used some that output 5.15 volts consistently, and some just 5.0 volts. Some have two micro USB connectors, some do not. I have a few of these I use now that are very reliable. eBay is a good place to find them.
I guess for $13 you get some and see what happens. You can also afford to get a few as backups in case of failure.
In my shack, I use a West Mountain Radio PG40S power gate which takes 15 volts from an old Radio Shack analog power supply, and outputs about 14.8 volts to a Anderson Power Pole power block, and keeps a Type 27 deep cycle battery charged. From the power block I use a few of these DC-DC step down modules to convert to 5.1 volts. I have the same setup at my home (shack is in a different location) with a smaller battery to power the PiGate development devices and a radio. If the power fails, the battery is switched in instantly and give me enough power to supply my PiGate RMS station for a day or so, or my home development site for about 12 hours.
There are lots of solutions. Experiment!
j4home DC-DC Converter Step Down Module 12V to 5V Micro USB Power Adapter (Ring Alarm keypad Compatible)
On Wednesday, June 3, 2020, 12:29:02 PM CDT, Tadd KA2DEW in NC via groups.io <tadd@...> wrote:
What we need is a 9 V to 15 V DC input device which outputs 5.1v regulated to a USB socket and which delivers that voltage reliably automatically when the input voltage is applied (not like the new DROK device which requires menu manipulation to turn on the USB output). Most of the devices that are close to these specs only put out 4.9 to 5 V which is not enough for the PI 4B. Or, they use screw terminal outputs which is not good for the casual Raspberry PI software engineer. Sockets are good.
We’d further like this device to be $20 or less. I’ve seen things which are really close to what we want for as little as a couple of dollars. But close doesn’t count here. It has to be 5.1 VDC and it has to be always on, and it has to take DC input.
Would it be worth $40 to have a 3 Amp linear supply through-hole KIT that does the above? I have a schematic for a circuit to do this and handle charging, switchover, and relay protect for a GelCel UPS and early protection alert to Raspberry PI when the battery is getting close to damaging itself. WN8P did the schematic. We’re pondering making and selling PCBs (for cost via ETSY) and publishing a bill-of-materials for builder purchase from DigiKey.
The design seems expensive. I’m just wondering if it is worth it. The cost includes the heat sync but no housing or Gel Cel. Dunno. It seemed a good idea at the time. I can do really good kit building instructions. See this page: