[Lowfer] QRSS Alternative (LONG)

[John Andrews]

Regarding Lyle's comments on proposed BW in the 136 kHz band:

If the band arrives in the U.S., I will be using a high power audio
amplifier, which  runs in a linear mode. This will allow shaped keying ahead
of the amplifier, and should offer clean operation for the various amplitude
and phase shift keyed modes. I probably wouldn't have taken this route if
the power limit had been based on ERP, but 100 watts of linear output is
pretty easy to do. My dummy load tests show that I could do a pretty clean
200 watts with the amp I'd be using. That's with a 1:2 transformer on the
output, driving 50 ohms.

Now, there's nothing wrong with using Class C, D or E amplifiers down there.
But you may need to give some thought to shaping the output by keying the
power supply with time constants on the rise and fall.

John Andrews, W1TAG