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Best TX Filter Settings for CW, RTTY, FT8, FT4, SSB?

Lawrence Libsch
Lawrence Libsch Member ✭✭
edited November 2020 in Third-Party Software

I operate with a Flex 6600. I seek guidance on the optimal TX filter settings for the modes I use. I'm comfortable with RX filter settings, but need help with TX filter settings.

I would like to be confident that my TX signal is clean and powerful.

Larry, K4KGG


  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin

    @Lawrence Libsch CW does not utilize a user adjustable TX filter. Digital mode TX filters should be set to the bandwidth recommended for the specific mode. For SSB, utilize the appropriate filter for the manner in which you are using it (DX, contesting, ESSB - there are lots of references on the Internet covering this subject).

    Because the radio utilizes a DUC and brickwall DSP filters, nothing outside of the filter bandwidth is sent to the PA. You just have to be mindful of not over driving the input signal so that it exceeds 0 dBFS (digital clipping) to ensure you have a clean signal.

  • Thanks for the advice, Tim. I will search for articles about TX settings for SSB. I do understand how to monitor my signal for over driving. One of the fun things about the 6600 is that it has so many capabilities that there is always something more to learn and try to improve the experience.

    Larry, K4KGG

  • John KB4DU
    John KB4DU Member ✭✭✭✭

    I have a suggestion. There is little intelligence in a voice signal below 300 hz or above 3500 hz., so that is where I set the transmit bandwidth. I don’t adjust the transmit eq when using the flex hand mike. If you do need to use the eq, cut before boost to get what you need. There are suggestions here about techniques to hear your voice, but it depends on the model flex you have.

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