moderated Re: Class C PA on FT8? #FT8


John McHarry
 

I was thinking more of driving the rf stages nonlinear.

On Fri, 2021-01-29 at 14:07 +0000, Bill Somerville wrote:
Hi John,

not quite sure what you are referring to, but note that over-driving
the audio input of a transmitter is very different from running an RF
stage in a non-linear class of operation. The key difference being
that the harmonic content is at multiples of the base frequency +
modulation frequency. When the base frequency is zero those
modulation products are very close to the wanted frequencies and
harder to remove.

73
Bill
G4WJS.

On 29/01/2021 14:02, John McHarry wrote:
Then why not overdrive a transceiver?

On Fri, 2021-01-29 at 13:21 +0000, Bill Somerville wrote:
On 29/01/2021 13:08, Steve Kavanagh via groups.io wrote:
Thanks, Bill. I stand corrected. I hadn't realized it was
possible
to introduce some pulse shaping without some amplitude
variation.
I
won't worry about class C (or D) amps, then!

73,
Steve VE3SMA
Hi Steve,

it is the frequency transitions that are smoothed, not the
amplitude.

73
Bill
G4WJS.


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