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Transverter power limit doesn't appear to be limiting.

Just got my Q5 transverters for sat and eme work. I noticed that no matter what I set the power limit to, including 0 dbm under the radio setup, xvtr tab. that I can still get full power with the RF and Tune power sliders.

What am I missing?

Brian KA7KDX


  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Hi Brian, 0 dBm is 1 milliwatt, so depending on the input requirements of the transverter, this might be expected behavior. Try -10 dBm and see if you see a difference.

  • Erika - KØDD
    Erika - KØDD Member ✭✭✭

    Len beat me to it... What was the spec recommended by Q5 when you ordered it. Helps to know what signals the new guy needs to work. Then you can control it from there. Enjoy. Erika DD

  • Joel N9LQ
    Joel N9LQ Member ✭✭

    In the Q5 documentation, they describe how to set the **** on the underside of the transverter. If my memory is correct, this **** affects the input sensitivity of the transverter. If this is set correctly, you should be able to have the Flex controls work as expected.

    73, Joel

  • Joel N9LQ
    Joel N9LQ Member ✭✭

    The **** are for an apparently disallowed slang for a variable resistor.

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

    To align the transmit side of the Q5, you do the following - this also depends on the parameters that you asked for when you ordered the Q5. Most are set to a 10dbm max drive.

    • Turn down the RF TX gain to minimum on the Q5
    • Set the Radio to a 10dbm output power (full transverter power)
    • With the Radio in a constant carrier mode, such as FM or CW, slowly turn the Q5 **** and watch the RF power out
    • Make sure your power supply for the transverse is 13.8V at minimum
    • Stop when the Transverter hits maximum RF out (25 watts as example into a dummy load)
    • -- OR -- stop increasing the power **** until the RF power out from the transverse does not increase any further.

  • KA7KDX
    KA7KDX Member ✭✭
    It still appears that the limits have no effect on the power to the transverter. At least looking at the rf meter on the front. Setting the RF slider to 50% I would expect that if I set the limit to 0, that there would be a decrease in the indicated rf power on the meter, but it doesn't appear that there is. I don't have a wattmeter so I can't confirm that the output power isn't varying. But you would think that limiting the input power would reflect on the meter.
  • KA7KDX
    KA7KDX Member ✭✭

    Just confirmed on my 144MHz transverter that the power limit has no effect. 0dbm or 10dbm with the **** set to minimum power and setting the slider to max, both put out the same amount of power.

    I adjusted the variable resistor to have the transverter put out about 90w while keying with FM with the limit set at 10dbm and the slider for 100, then I set the limit to 0dbm and got the same 90w. Even tried setting at -10dbm, no change, still 90w

    these are the specs on my transverters 144MHz High Power 150W Transverter

    IF Configuration: Common IF

    - RF Configuration: Common RF HP

    - IF Drive Level: 0dBm to +20dBm

    - PTT Polarity: Low (GND)

    - Local Oscillator Stability: High Stability 0.28p..

     Custom IF: Standard IF - 28MHz

    432MHz High Power 50W Transverter

    - IF Configuration: Common IF

    - RF Configuration: Common RF HP

    - IF Drive Level: 0dBm to +20dBm

    - PTT Polarity: Low (GND)

    - Filter Tuning: Wideband 430 - 450MH..

    - Local Oscillator Stability: High Stability 0.28p..

    - Custom IF: Standard IF - 28MHz

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

    It sounds like you have not aligned the Q5 correctly. It does not come from the factory aligned for your IF radio. You do have to do this alignment procedure.

    If the TX IF gain on the Q5 is set too high, then no matter what you do, the output will be 100% from the transverter.

    Follow the above instructions and start with TX IF at minimum and the radio set to 10dbm at 100%. This will provide a 10dbm carrier to the transverse.

    Even if you don't have test equipment, Just watch your watt meter and increase TX IF until the power hits the most you can get out. That is when you know that 100% from the radio produces your maximum power out regardless what the actually wattage is.

    Based on your comments, you are over driving the transverse and there is a risk of causing damage and also causing a very distorted transmit signal.

    This is why the Q5 transverters come with a TX IF adjustment.

    The same is true with the RX IF. You have to adjust it based on the instructions that come with the Transverter.

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