6600M Tuner does not stay selected

John,

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.

25.1 MODES OF OPERATION
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.

73,

Mack
W4AX
Alpha Team