Evan,
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A linear amp for the QMX is a possibility, could work well.
Could just use that Elecraft 100W amp, at $1429 they have the budget for
a very nice amp.? But a major advantage of the QMX is EER transmission,?
which can use switch mode FET's in the final with no concern for linearity.
?
A beefed up QMX at 100 Watts might have the same design as the current QMX,
just beefier parts on the last page of the schematic.? The modulator should be made
a class D audio amp, not the linear amp we currently have, which would be a
bunch more parts.? Such a beefed up QMX should cost much less than
a QMX + linear, have a cleaner signal, and be extremely efficient with power.
A single board SSB transmitter at more than 5W often has trouble with RF
from the final getting into various stages of the exciter.
That may not be an issue with the QMX, when transmitting all we have is CLK2
from the Si5351 feeding the final, all RF is at the same frequency.
Would still have to guard against RF getting into microphone cable and modulator,
but EER should make for a much simpler and cheaper 100W SSB transmitter.
?
Jerry, KE7ER
?
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On Wed, Mar 19, 2025 at 08:19 AM, Evan Hand wrote:
Jerry,
?
I was thinking along the Elecraft KX line competition.? Elecraft offers a 100-watt amp for the KX2/3 radios:
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Ideally, it would be 100 watts, but 50 at the right price would be good.
?
Currently, the QMX+ can be compared to the KX2.? The QMX is short on the number of bands.? At almost 1/10th the price, the QMX series is a steal.
?
73
Evan
AC9TU
