Jerry,
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We may be getting too far off-topic and need to start another thread.
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A company tried an external EER linear amp (The Polar Explorer) highlighted in the March/April 2017 QEX (I have a subscription to QEX to read it.? I do not know if I can publish the article as the content may be copywritten).? The company never made a viable commercial product that could compete with the AB class amps.? Hans overcame the EER issues in the QMX by using the "calibrate" function to align the amplitude and phase components in the QMX.? That would need to be done for an external amp IF using the QMX EER approach.? Adding the circuitry to break down the input into amplitude and phase signals at RF frequency and power adds complexity and cost.? That is already done in the QMX at low signal levels, which makes it much easier to work.??
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As you suggest, the best approach to keep with the EER design is to beef up the internal PA of the QMX by offering a QRP and QRO option.? That could change if Hans or another developer develops a low-cost way to manufacture an EER-based amp.
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73
Evan
AC9TU
