[Amps] Tuner Loss

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Thu, 10 Mar 2011 11:40:19 -0500, "Carl" <km1h at jeremy.mv.com> wrote:

>
>165W of loss in a well constructed tuner shouldnt even be a discussion 
>point. Tank circuit loss in a 1500W amp is much more and we accept it as 
>normal.

REPLY:

Absolute nonsense. Apples and oranges. 

Reactances such as found in a properly designed tuner should be nearly
lossless. A linear amplifier can not be lossless because a sine wave is
being amplified. As the tube transitions from zero anode current to peak
anode current and back again, it appears as a changing resistance over
the RF cycle. As a resistor, it dissipates power and this is
unavoidable. 

No such thing happens in a tuner.

Basic tube and AC theory, Carl. Time to hit the books. 

There are amplifiers which go from zero anode current to max anode
current and back in a very short time and do not have the dissipation
problem, but those are NOT linear amps. Class D is one such example. 

73, Bill W6WRT