[TenTec] Power supply types

[Ken Brown]

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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