Re: A couple QDX questions: 60 meters? & 9v vs 12v
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Just like with any other regulator design you want to use low ESR capacitors.? MLCCs usually are, tantalums usually are, and disk ceramics usually are.? Verify before whipping something together out of junk box parts.?
That schematic is fine for use with a low ripple input supply or battery.? ? If building an AC to DC linear supply much more capacitance is needed on the input and it doesn't hurt on the output.?
Fred W0FMS?
Hi Bill,
I just used the typical 78xx schematic and MLCC capacitors that I had on hand. E.g. Mouser 581-SA115E334ZAA or similar. I don't think the component choice is terribly critical, but MLCC is what I usually use and have available.
Cheers? Gregg W7GRM
I am building mine for 9V for the same reason, to use with batteries.? I have a couple of different switching converters and can always do a linear regulator for home use.
I also think that 9V will be better for the AMS1117 regulators over time than 12V will be.?
Fred W0FMS?
On Wed, Nov 10, 2021, 9:26 AM Bill Lamm < kd9mdl@...> wrote: Gregg W7GRM..? I have been thinking on the same lines.. possibly overthinking as I look at your picture.. I have some 3s LiFiPo surplus batteries that should power the QDX and Raspi for a weekend..
could you elaborate on you componeny choices? Looks like ceramic caps?
Thanks
KD9MDL
Bill
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Fred Spinner