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6600M Tuner does not stay selected

John K0TG
John K0TG Member ✭✭
edited April 2019 in FLEX-6000 Signature Series
Lately I have been playing with FT8 on two slices.  When I did that and had the tuner selected for a particular band, all was well.  Lately, I cannot keep the tuner (ATU) selected to be active on any band.  

In SmartSDR I select the ATU and I get a success message.  Then go to the other slice and select the ATU and see the success message.  I would think all is well.  But when I go back to the other slice the ATU is unselected.  I'm not sure what changed to cause this behavior as it used to work just fine.

Any ideas?

73, John  K0TG


  • Mack
    Mack Member ✭✭✭
    edited March 2019

    Please read section 25 of the SmartSDR manual for a full explanation. Please ensure you have MEM selected on and It should be working fine.

    There are two modes of ATU operation; manual and memory. In manual mode, the user initiates an ATU tune operation to attempt find a better match between the PA and the antenna system, but the inductance (L) and capacitance (C) values are not retained and the ATU will revert to bypass mode if the frequency or band is changed. Memory mode is an extension to Manual mode where the L/C values are retained and automatically used when the frequency of the transmit slice is within the ATU Match Frequency Range (with the same TX antenna selected).
    What constitutes a successful ATU match? The ATU will try to impedance match the load to as close to a 1.1:1 SWR as possible. If the ATU measures an SWR of 1.1:1 or better at the beginning of the matching process, SmartSDR will leave the ATU in bypass and report Success.
    A successful ATU match on 6m occurs when the SWR is improved from the initial SWR determined in the bypass state and is better than 2.32:1. For non-6m operation, a successful ATU match is one where the SWR is improved from bypass SWR reading and is better than 1.7:1.
    The ATU will stay enabled but the ATU status indicator will not report Success if the SWR improved from bypass but does not meet the above SWR criteria. If the resulting SWR after an ATU tuning operation is not better than when in Bypass and the above SWR criteria is not met, the ATU goes into Bypass (ATU button is not illuminated) and ATU status indicator does not report Success.
    ATU Match Frequency Range – After the ATU has found a successful match, the inductance (L) and capacitance (C) values are valid for a 200 kHz frequency span centered at the frequency the ATU tuning operation was initiated, or +/- 100 KHz. Once you tune the frequency of the transmit slice beyond that range, the ATU will be put into Bypass mode. The only exception is if there is another previously saved ATU memory frequency contained within that ATU Match Frequency Range and you have ATU memories enabled.


    Alpha Team

  • John K0TG
    John K0TG Member ✭✭
    edited March 2019
    Thanks Mark!  That was it exactly.  If I would have hovered over the MEM button I may have figured it out;  It says "Enable memories for the ATU".  Somehow I must have unclicked that option.

    73, John  K0TG

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