On Mon, 11 Jun 2018 23:28:23 -0700, Wyll Surf Air wrote:

If there is a specific voltage converter that seems to be spitting out a
lot of noise you might try wrapping it in tin foil. That has worked for
me in the past.

A cheap source of efficient 12v - 5v converters is to buy 'USB cigar
lighter chargers' from Ebay, throw away the plastic case and solder power
leads onto the 12v side of the PCB. However, these often produce RF noise
because they use a high frequency chopper circuit. I use them, of course,
since they are cheap and easy to find but I mount them inside a small
metal, rather than plastic, box and fit ferrite cores to both 12v and 5v
leads close to the box. I have no noise problems if they're used this way.

The only serious interference noise problem I've had was from a
mechanical T&B. Ferrite cores made no difference to it. The cure was to
fit a "12v interference suppression capacitor" across its its power
leads. These are special purpose polyester film capacitors. Mouser, among
others, sell them or a search using the term shown above will find many
sources, including fleabay.


--
Martin | martin at
Gregorie | gregorie dot org