Interaction between RF Power slider nad TX Gain slider

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I have a question about the interaction between the RF Power slider and the TX Gain slider, especially for the digital modes using DIGU and RTTY. Running a 6300 with the latest SSDR.

I want to avoid overdriving anything which would produce splatter or other IMD products.

Let's say I want 25 watts of RF out using JT65 mode. I see two ways to accomplish this:

1. Set the RF Power slider to 25 watts and the TX Gain slider to something around there or higher.


2. Set the RF Power slider to something above 25 watts and use the TX Gain slider to limit the power to 25 watts.

Either way will give me 25 watts of RF output, but is one preferable over the other?  I suspect it would be #2 but I want to hear from the experts.

And finally, is DIGU different from RTTY in this respect?

Many thanks for your help and advice.

73, Bill W6WRT

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Bill Turner

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Posted 4 years ago

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Steve (N9SKM)

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Total edit. Are you using dax?
I set my dax output on the computer to get just under a clipping level (No overdrive) using the level meter in ssdr and the rf power slider to adjust output so I get full modulation. Power slider is called that for a reason.

If you overdrive the audio circuit that is what causes splatter and overmodulation not the radios power output level.
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Neal - K3NC, Elmer

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I set the TX gain to be slightly below AGC kicks in (as you do with phone settings) and then leave it there and manage power from the power slider. Have always done this as it just makes since to leave gain settings alone.

The only difference (as I understand it) between RTTY and DIGU is that RTTY has offset and tone markers (as well as filter width) defined for high tones RTTY.
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Tim - W4TME, Customer Experience Manager

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Set the DAX audio gain level so that the input (mic) meter is peaking around -3 dB.  Then  adjust your PA drive level to a setting appropriate for the digital mode you are using.