FLEX-6300 CW output power adjustment

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  • Updated 5 years ago
A few FLEX-6300 customers have mentioned that output power on CW is lower than the output power on SSB.  We have looked at several different radios and found that the power offset is typically 0.3 - 0.7dB lower with CW due to the different path that RF takes through the radio when operating QSK.  At most, this amounts to a roughly an 85W output when set to 100W (your mileage will vary).  15W difference sounds like a lot, but to keep this in perspective, an S-Unit is 6dB so this is only 1/10th of an S-Unit difference for a receiving station!  Nevertheless, we want to account for the difference so the radio is a full 100W output on CW as well.

When the radio was designed, it was assumed that there would not be an offset in the paths so the calibration difference was not accounted for along with the myriad of other calibrations in the radio (board losses, filter losses, PA gain variance, etc.).  It may be interesting to note that the difference is not a power loss (it is not power dissipated in the radio), but is a generation offset (less power is produced).  As a result of this discovery, we have updated the calibration algorithm which will offset the power for CW to overcome the difference.  The change has already been coded and tested and we will be releasing this as a point release software update in the next several weeks (this along with other fixes will first be tested by the Alpha team, etc).
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Steve - N5AC, VP Engineering / CTO

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Posted 5 years ago

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