[Elecraft] KPA-500 "Output for Input" schedule?

[Julian, G4ILO]

Don Wilhelm-4 wrote:
> 
> Of course it can be driven by lower power.  The KPA500 is a linear 
> amplifier.  If 40 watts in produces 500 out, then 20 in will give 250 
> out and 10 in will produce 125 watts.  If the relationship is otherwise, 
> then it is not acting as a linear amplifier.  The same thing should be 
> true for any linear amplifier - that is the definition of linear
> operation.
> 

If it does that then it will be the first linear amplifier I have ever seen
that actually keeps that relationship across the whole of its range.

Most solid state amplifiers exhibit noticeable compression as you increase
the input power, so you get a lot more than half the rated power out for
half the specified drive power.

Take a look at the figures for this Mirage amp (selected at random as being
the first spec sheet I could find that proved the point.) It is only truly
linear up to half its rated output. 10W in gives the rated 160W output, but
5W gives you 150W 2.5W would give you somewhere around 120W. The VHF amp I
have here has a similar characteristic. Although it is designed to be driven
with 5W input I am actually driving it with the K3/K144XV with less than
half that power and still get virtually full output.

So I think the OP actually asked a very reasonable question.

-----
Julian, G4ILO. K2 #392  K3 #222.
* G4ILO's Shack - http://www.g4ilo.com
* KComm - http://www.g4ilo.com/kcomm.html
* KTune - http://www.g4ilo.com/ktune.html

--
View this message in context: http://elecraft.365791.n2.nabble.com/KPA-500-Output-for-Input-schedule-tp6352735p6353030.html
Sent from the Elecraft mailing list archive at Nabble.com.