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FT-8 continuous for 1.5 hours @ 90W. OK or problem?

My wife and I run FT-8 for extended periods, and we've had two fan failures in our first week, as indicated by slow single red blinks.

Should the radio be able to handle continuous FT-8 (50% duty cycle) at ~90W indefinitely?

When I pressed the power button to power down and reset the fan, the radio immediately started flashing 6 blinks, indicative of low voltage. But my 40A PS is rock solid at 14VDC.

Is this transition normal behavior?

Once it started blinking 6, attempts to shut down the radio via the power switch including very long (30 s) presses would shut down the radio, so I had to simply turn off power.

Following the cold boot" process brought the radio back up.




  • RFord
    RFord Member ✭✭✭

    This will provide you with additional information on your FT8 duty cycle and cooling issues associated with running FT8 for extended periods…

  • KM4CQG
    KM4CQG Member ✭✭

    This is a strain on your Radios output. FT8 is **** your finals it shouldn’t be ran at 90 watts continuously.

    The solution is get an amplifier run the Radio at lower power and don’t run the Amp over 50% .

    This type of setup you can run nonstop.

    Best of Luck


  • Al Simons
    Al Simons Member ✭✭

    Thanks, folks. I'll crank her down to 50% and see if that stops my fan problem. But in all honesty, I would think that the PA getting too hot would result in a self-regulation reducing the power, OR an over temperature error as is indicated in section 42.1 of the SmartSDR Users Guide, not a fan failure error.



  • KM4CQG
    KM4CQG Member ✭✭

    The Fan failing probably is a separate issue. It could be a by product of the heat just not sure.

  • John KB4DU
    John KB4DU Member ✭✭✭✭

    The single red flash can also happen due to comm interruption between pc and radio.

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    If the radio detected a low voltage, it is possible the voltage was low in the Radio or at the connectors on the back of the radio when under full load.

    I would do a visual inspection on the Power Pole connectors and make sure they look ok. Sometimes they get knocked out a bit and that causes a high impedance situation and they can overheat if high current is drawn.

    Ohms law issue :)

    I would also install FRStack and us it to read the internal voltmeters while in transmit. Make sure the voltage does not drop below 12v while in TX.

    If the radio gets too hot, it will dial back the power. Again, FRStack will show the temperatures. If the radio is too hot, the fans will speed up.


  • Al Simons
    Al Simons Member ✭✭

    Radio is a week old, the connectors are fine. [smile] (Yes, I did check.)

    Thanks for the pointer to FRStack; I was unaware of it. I'll go play.



  • Ron Koenig
    Ron Koenig Member ✭✭

    Several times a year I operate FT8 in SO2R for 24 hours at a time @ 100 watts output. As close to 100% Duty cycle as you can get. The radios have never complained.

    I suspect you have a Power issue

    Ron, WV4P

  • Al Simons
    Al Simons Member ✭✭

    Help desk ticket submitted after another incident today, with FRStack running and showing good voltage and reasonable temperature. Working with staff to run some diagnostic tests. We'll see what happens.


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