Re: K3: Adjusting SSB modulation for proper PEP rating

Posted by Don Wilhelm on Apr 23, 2018; 10:52am
URL: http://elecraft.85.s1.nabble.com/K3-Adjusting-SSB-modulation-for-proper-PEP-rating-tp7640357p7640358.html

Ed,

The power you request with the power knob is the PEP level that the K3
will control.  That is regardless of mode.
The K3 compensates for the mode automatically.

The same should be true of the transverter output.

73,
Don W3FPR

On 4/23/2018 4:56 AM, Edward R Cole wrote:

> Since the K3 operates so differently (than traditional radios) for
> proper modulation I thought I'd ask this:
> In olden days amplifiers were rated in PEP typically as 2x average (or
> CW) power, so for AM one had to set carrier at 1/4 full carrier output
> to stay linear. (1/2 carrier  for SSB).
>
> But now I am setting up a 600w linear amp to run at P1 which is about
> 0.9 of P3 (saturated power) and wondering what level of carrier power to
> run in SSB to stay linear and also not to overdrive and stress the
> expensive LDMOS device in the amplifier.
>
> I'm running the K3 in transverter mode on 28-MHz so max output is
> 1.5mw.  I can view this with a scope.  The amplifier is running at
> 1296-MHz which is too high a freq to monitor with my scope.  I can only
> observe average RF power from a directional coupler and diode detector
> (like a Bird meter).
>
> Normally, I just set power on the K3 to drive my amp to nominal full
> power and select SSB mode.  Modulation level is set by observing ALC
> meter.  I is ALC showing five bars when saying the word "five" loudly
> and six bars with compression.  So does this mean the K3 automatically
> adjusts RF power in SSB to stay linear with proper modulation audio
> setting?
>
> My reason is when running 1296 SSB to avoid overdriving the amplifier
> into P3 possibly causing harm, as much as not wanting to produce
> non-linear products.

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