Re: QMX+
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Like the QMX, the QMX+ already has an output of about 5 watts. The 10 watt linear amplifier would not be a huge increase in power, barely worth the trouble. And you would have to drastically decrease the output power of the?QMX somehow; the amplifier is designed to require 25mW input power. (One possible way would be to build the QMX for 12 volts, run it at 6 or 7 volts, and then use some attenuation between it and the amplifier.) ? Hans originally designed that amplifier to be part of the never released (to the general public, to date) QSX, which was to be a 10 watt SSB and CW radio (single band with a multi-band option) using a conventional design with a low power modulator stage followed by a linear amplifier to get to 10W. Hans released the amplifier as a separate kit for use with homebrew designs, and for use with QRPP designs like the Softrock Ensemble RXTX (maximum output around 500mW). Hans plans to work on adding SSB capability to the QMX by using EER (envelope elimination and restoration), a technique where SSB can be generated at full output, eliminating the need for linear amplification.(EER separates the frequency and amplitude components and applies them separately; on the QMX+ the frequency component will likely be done by programming the Si5351A, while the amplitude part will be done by controlling the drive to the final output stage.) That will not use the linear amplifier stage from the QSX. In addition to SSB voice, that will make it possible to transmit multi-tone digital modes. EER has the advantage of much higher efficiency but is more complicated to implement. On Thu, May 16, 2024 at 5:42?PM Dave VE3GSO via <VE3GSO=[email protected]> wrote: Hi Doug H and all. |
Shirley Dulcey KE1L