Reduce output below 5W with FT991

Discussion in 'General Technical Questions and Answers' started by DJ7ZZ, Sep 13, 2021.

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  1. DJ7ZZ

    DJ7ZZ Premium Subscriber QRZ Page

    Hi everybody,
    i´m running a Transverter and want to reduce the 144MHz output of my FT991 below 5W.
    Are there any settings that I can change in the menue?

  2. G8FXC

    G8FXC XML Subscriber QRZ Page

    Nothing in the main menu. There may be something in the service menu, but you have to be very careful about tinkering around in there!

    Martin (G8FXC)
  3. DJ7ZZ

    DJ7ZZ Premium Subscriber QRZ Page

    I´ve the Service Manual here, but I can´t find the Settings I have to set.
  4. G8FXC

    G8FXC XML Subscriber QRZ Page

    My guess is that it is one of the ALC or TXG settings. I remember seeing someone boasting of having been able to get the output power increased to 70W - but I don't remember which setting they were tinkering with. The same setting should equally be able to reduce the maximum output power. For heavens sake make detailed notes of all the settings before tinkering - they are specific to each radio and difficult to set without laboratory quality test gear!

    Martin (G8FXC)
  5. G8FXC

    G8FXC XML Subscriber QRZ Page

  6. AA5MT

    AA5MT Ham Member QRZ Page

    Easy way - Turn the mic gain down! No input, no output.

  7. DJ7ZZ

    DJ7ZZ Premium Subscriber QRZ Page

    Thanks Tom for that answer. You know about the Problem of Spikes or peaks If you start transmit or have you ever worked with a Transverter?
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Yes, turning the mike gain down is not a workable idea.

    However, just adding a 3 dB or 6 dB (or whatever is needed) 5-10W resistive attenuator in the line to the transverter can work fine. Most transverters have substantial I.F. gain (generally more than needed), so losing a few dB at the baseband frequency doesn't impact receiver sensitivity at all but will cut down the transmitter power available, even on spikes.
    N5HXR, WA9SVD and K0UO like this.
  9. AI5DH

    AI5DH Ham Member QRZ Page

    That would require knowledge.
    K0UO likes this.
  10. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    Most good transceiver s for
    Transverters use have a low power output designed for Transverters use. Probably even separate receiver and transmitter jack's. If you're using a radio that doesn't/ then you face problems of too much power or burning up the transverter which many of us have done over the years.

    So I strongly suggest that you find a different radio with Transverter outputs.

    Yes there are ways to do it with attenuators but you can get yourself in trouble pretty quick.

    73 from,
    The K0UO " Rhombic Antenna Farm" 2 miles of wire in the Air & On the daily

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