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6600 Transmitter Duty Cycle?

What’s the duty cycle rating of the 6600’s transmitter? Can I run 100 watts in a 100% duty cycle mode like RTTY indefinitely, or is there a time limit?


  • Pete La
    Pete La Member ✭✭
    For true 100% duty cycle you should cut power back to no more than 50%.
    Pete K1OYQ
  • Thank you. That's disappointing.

  • KD0RC
    KD0RC Member, Super Elmer Moderator

    @Pete La Is that true of the Flex 6000 series radios? Some radios and some amps require reducing power as you describe, but I do not see anything about that in any of the Flex documentation. Have I missed something?


    Len, KD0RC

  • Chris_DL5NAM
    Chris_DL5NAM Member ✭✭
    edited November 2020
    Define 100% Duty Cycle ! Over a minute, over 10 minutes, over hour, a day, ..... Sorry, none of ALL our device cant run 100% duty cycle! No TRX, no PA. And 100% of any mode is not Ham like = it's not a QSO - we dont have radio broadcast stations.
    73 Chris
  • My Alpha amp can run legal limit output indefinitely. You may remember their ads in the ham magazines? The ones with the brick on the key? They used to do this at big hamfests too--they'd set up the amp on a table connected to a beefy dummy load, and put a brick on the key and it would run this way all weekend.

    IMO, advertising a rig as having 100 watts output should mean that it can run 100 watts indefinitely. If it can't, it should say so in the specifications.

  • John KB4DU
    John KB4DU Member ✭✭✭✭

    Temperature is the controlling factor for the radio. It can be monitored with multiple software products, like the meter from K9DUR, but the radio will shut down before damage occurs. For some applications, continuous operation is required, but for ham radio, like most two way communications transmitting is not continuous, since listening is required. So most specs say “ICAS”, intermittent commercial and amateur service. FT8 is among the most demanding with a 50% duty cycle. I have run FT8 for up to an hour into a dummy load. The fan speeds up, but the 6400 keeps going.

  • Pete La
    Pete La Member ✭✭
    I guess you'll have to ask the experts for the exact answer, or test it out and let us know what happens. Most 100W rigs cannot take 100% duty cycle for very long. Temperature dissapation in the finals is the main factor, even for our humble Flex-6000 series wonders. Amplifiers are a different story depending on how much head room they design into them (ex, Alpha and a couple of others, maybe even the Genious?). I too see nothing in the manual one way or the other, so I will err on the side of caution and stay below 50%. Sorry I couldn't be more help.

    Pete K1OYQ

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