They are both commonly available and they can both be used to power
typical HF transceivers. I think it is a reasonable comparison to make.
Here is another question: What kind of power supply did you first see
reviews in QST in which the subject of RF noise generation was even
mentioned?
Yes, switched mode power supplies CAN be made that do not generate (and
radiate) RF noise. And switched mode power supplies are generally more
energy efficient.:
How about we state the question this way:
Suppose you're on vacation and you brought your mobile rig along with
you, which runs on 12 VDC. You planned on only operating from your
vehicle, so you did not bring a power supply for use from 120 VAC. You
are offered an opportunity to stay for free in a nice vacation rental
cabin for a week. The cabin has all the conveniences, including grid
power. There are tall trees and you have a spool of skinny copper wire
and an antenna tuner in your vehicle. You think it will be a great
opportunity to get on the air from a remote location, with hopefully not
a lot of RF noise. Before you head up into the mountains to the go to
the cabin you see a store which sells two kinds of power supplies that
have the right voltage and current rating to power your rig. One of the
power supplies is very lightweight and the label say it is super
efficient and uses switching mode technology. The other power supply is
heavier, and you can see it has a laminated iron core transformer and a
big electrolytic capacitor in it. The prices of the two power supplies
are identical and they both appear to be well constructed. You cannot
find any other data about these power supplies. The drive to the cabin
is long, and you don't intend to drive back to town until you have
finished your stay at the cabin. If you buy both power supplies, you
won't have enough money left to buy the wrist rocket slingshot you
intend to use to send the skinny wire up into the tall trees.
Which power supply would you buy?
DE N6KB
On 1/20/2014 3:41 PM, Kim Elmore wrote:
This is an apples vs pecans question.
Better-stated questions:
What's the probability that a properly-designed and engineered linear
power supply will radiate RF noise of sufficient amplitude to be
bothersome?
What's the probability that a properly-designed and engineered
switching power supply will radiate RF noise of sufficient amplitude
to be bothersome?
Answer: unknown. likely small but equal.
Kim N5OP
On 1/20/2014 7:13 PM, Ken Brown wrote:
What is the probability that a transformer/rectifier/capacitor
filter/linear regulated power supply will generate and radiate
(through AC power input or DC power output leads) RF noise of
sufficient amplitude to be bothersome? That probability may not be zero.
What is that probability that a switched mode regulated power supply
will be not "properly engineered" and generate and radiate RF noise
of sufficient amplitude to be bothersome?
How do those two probabilities compare?
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