Craig,
The old SMPS/linear supply finer points have been around a while,
and while I use a switcher here on one set with what I perceive to be no
switching noise at all, it is a different story if I re-locate to a beach
house we have where the ambient noise is virtually zero. There, the SMPS
difinitely has a low level of noise ....mainly on the lower bands....that
manifests itself as a low level "mobile" rasping that drifts around slowly
every few khz . At home I would swear it was clean.( and I have a quiet
location for all intents and purposes)
However, the small amount of switching noise doesn't worry me for the short
times I am portable, and the convenience of not putting an arm out of joint
carrying around a transformer derived supply far outweighs any noise I
encounter. Having said that, if you want completely noise free operation,
then the linear supply will win hands down.
I have used home made switchers that I have put a lot of effort into trying
to get "absolutely" clean and never 100% achieved that goal. I eventually
fell back on MFJ switchers, which I find as good as any, and there is a $99
model that is small, light and very portable, and probably as "clean" as you
will get in a switching supply. There will be others on the market much the
same ( Samlex?)
To round up........you can't beat the switchers for portability and
convenience, but buy a "Brand name" model. In most suburban or density
locations you probably won't notice any noise.
However if you are going portable where man made noise doesn't exist, the
Linear supply, or batteries will win out every time. It's the old story of
YMMV.
Cheers......Ron ZL1TW
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