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MEffA Question

Roger W6LAX
Roger W6LAX Member ✭✭
edited September 2021 in Power Genius XL Amplifier

As a new user I am asking if this Is normal:

Running CW into a dummy load on 40 or 20 meters with MEffA on, the amp will only put out 700-800 watts when I send with a paddle (no matter how hard I drive it). But when I key it with the macros of the N1MM program it goes to full power. The keyer and N1MM are both sending at 30 wpm. When I turn off MEffA, it runs full power with both the paddles and with N1MM.

Thanks, Roger


  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator

    What version firmware in your amp? What are you using for a wattmeter?

    Also open a Help Desk ticket to engage Flex support staff.

    Version 3.6.21 has much better power output metering..

    Dave wo2x

  • Roger W6LAX
    Roger W6LAX Member ✭✭

    I am using version 3.6.21 and using the PGXL watt meter

  • Dan-N7HQ
    Dan-N7HQ FlexRadio Employee, Community Manager admin

    MEffA is a "tuned" feature and will require retuning if you change frequency.

    Be sure to read Chapter 5 in the PGXL User Guide.

    MEffA does not work with signals with varying amplitudes, such as SSB, AM, or phase-shift keying digital modes like PSK-31. These modulation modes require more linear operation (class AAB). Though the MEffA indicator may be on, it is only operational in class AB operation and does not affect class AAB operation.

    To adjust MEffA for operation at the desired power level:

    • Key the amplifier with a "Tune" or drive signal to establish the desired output.

    • Unkey the amplifier and re-key. You may note that the amplifier has modified the LDMOS Drain Voltage and the output power.

    • Adjust the drive to re-establish the desired output level.

    • Repeat this process until the desired output power is consistently achieved.

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