On Jan 28, 3:27 am, "Richard" wrote:
I have an ex AM PMR radio that I wish to use on 144Mhz. I need a PSU feeding
24V @ about 300mA.

Are switch-mode powers supplies alright or are they too noisy to be used for
receivers? TIA.

The receiver I'm building uses switchers internally to take 5V down to
various other voltages. Total power supplied by the switchers is
around 20 watts. They're little open modules. I can "see" the
fundamentals (200kHz-700kHz range for these supplies) and the first
few harmonics if I go looking for them, but they're certainly not an
issue at 144MHz. With enough shielding and bypassing (done right), I
suppose any switcher would be clean enough. With a switcher of good
design, you won't even need any additional shielding or bypassing.

Cheers,
Tom