[Elecraft] K3 pwr out on digimodes

[Julian, G4ILO]

Ian White GM3SEK wrote:
> 
> 
> A sane engineer surely would; but the huge majority of transceivers are 
> trying to use the ALC loop for too many different functions including 
> gain levelling between bands, peak limiting and also power control.
> 
> [snip] 
> 

I seem to have read this before - perhaps in one of your RadCom columns?

Certainly I am making the assumption that ALC is used to control the power
to the level the operator has set, and that a responsible PSK operator has
chosen a level of perhaps half the rated maximum SSB output or even less. I
think Joe may be thinking of how older radios used to work, where the power
control varied the gain of the TX stages and ALC did only start to operate
once the rated output of 100W or whatever had been reached.

Since we are talking about digimodes here, and since the K3 like most other
modern radios has a separate mode setting for data modes, it is surely
possible for the ALC to act more slowly for data than for SSB, because the
amplitude of a data signal does not vary much, if at all, and the amount of
gain reduction needed over the course of a transmission will probably be
more or less constant once the initial level has been set.

Again, I must reiterate that this is what the K2 appears to do. At the start
of the first data transmission of the day you would see the RF output level
climb or fall until the selected value was reached, after which the radio
appeared to remember the setting used so that subsequent transmissions
always started at whatever power had been set.

-----
Julian, G4ILO. K2 #392  K3 #222.
http://www.g4ilo.com/ G4ILO's Shack   http://www.ham-directory.com/ Ham
Directory    http://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 
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