The biggest problem with switching supplies is that many of them tend to use switching frequencies that are in our band of interest (10-100 kHz). They don't HAVE to, but that's a sweet spot for cost and size. Unfortunately, many of the less expensive switching supplies don't provide sufficient filtering to fully eliminate ripple for a very sensitive receiving system such as the Blitzortung.
That's not to say that the filtering can't be added, or better filtered systems aren't available.
If it's helpful, here's what I did:
I decided to go with a simple linear regulated design.
The master supply (located away from the system) uses a transformer, regulator, and gel-cell battery backup to provide 13.8 volts. It uses an Altronix LPS3 board:
http://www.altronix.com/products/product.php?name=LPS3Admittedly, this is a bit overkill, as the system is capable of providing 1.5 Amps. Measurements with my Kill-a-watt meter have consistently pegged the Blitzortung system, with both E- and H-field amps, at about 0.5 Amps current draw (2.5 Watts at 5 volts).
Another option is the AL624:
http://www.altronix.com/products/product.php?name=AL624...which is available for around $10. I went with the LPS3 because this supply will also power some other weather instruments, which I'm working on. As is, the battery (12V, 9 Ah) should provide power for the BO for more than 10 hours, and of course it's expandable by adding more batteries in parallel.
Power is routed from this supply to the BO system in the attic using low-loss coax (LMR-240 equivalent).
Anyway, at the BO system itself, the power is stepped down via two LM1085 regulators. The first is adjustable and set at about 9.25 volts out; the second is a fixed 5 volt regulator.
Linear regulators typically provide about 60-80 dB ripple reduction each at 120 Hz, with somewhat less in the BO band of interest. Though the LM1085 isn't the quietest regulator out there, my overall noise floor is extremely low. And because the voltage regulation is accomplished via two regulators, there's not a lot of difficulty with heat dissipation -- perhaps 15 degrees C rise each above ambient.
Here are bench pictures of the enclosure; the regulator is in the right-hand compartment:
I certainly think there are commercial supplies that are more than adequate, but if you're in a building mood, a linear regulated supply is easy to construct (schematic attached).
