Setting Output Power

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What is the best way to set output power for digital modes on a Flex-6000? I have used the following two methods, but an not sure which is preferred for efficiency, etc. I like to run 25 watts output on these modes, so the examples below are based on this power output level.

1. Set the RF Power slider to 25 and adjust the DAX TX Gain slider until the "peak" bar in the Level bar graph is just below 0 dB.

2. Set the RF Power slider to 100 and adjust the DAX TX Gain slider until the indicated output power is 25 watts
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Jerry Gardner

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Posted 5 years ago

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Steve - N5AC, VP Engineering / CTO

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Official Response
If you didn't know anything about the system you were using, the general recommendation would be to keep the gain slider high and set the power low so that your signal into the radio has a high SNR.  In the case of DAX, however, everything is floating point rather than fixed point.  This is kind of an esoteric detail, but in a floating point system data retains its SNR independent of scaling.  So this is like saying that 0.444 * 0.25 * 10 == 0.444 * 10 * 0.25.  In a fixed point DSP system, you would likely lose SNR if you divide and pass the bits around first -- you would be lopping off bits and losing dynamic range.

TL;DR - Tim is correct, it doesn't matter.