There were a couple of recent reports of slow convergence on the operator’s target power level, AKA "power creep.”
Assuming that the operator has done a TX GAIN calibration on a given band, “power creep” on that band is probably due to higher than normal drive requirements. In such cases, a much larger DAC count may be required to hit full power, making granularity finer. The ALC will then take longer to converge.
We could attempt to converge faster, but slow convergence is safer under the circumstances, and should alert the operator to look into the issue.
If the rig’s current drain isn’t excessive at the target power level, then a workaround is to do a TUNE after changing the PWR setting.
As to the reasons for higher drive on one band, here are some possibilities:
1. very low load impedance seen by the PA (resulting in higher TX current)
2. mis-tuned band-pass filter
3. problem with band-pass or low-pass filter component
4. lower PA efficiency due to transformer leakage inductance, etc. (rare)
If you’ve experienced this and have further questions, please contact me directly.
73,
Wayne
N6KR
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