WSJT-X 1.9 Power drops off past 2500 Hz

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  • Updated 2 weeks ago
I'm sure I have a setting wrong somewhere , Using Flex 6600 , ssdr V 2.3.9 , WSJT-X V 1.9.1 . I noticed today when moving the Red goal post past 2500 Hz in FT8 the TX power drops rapidly . Ay 2500 Hz and below I have power set to 80 watts ! If I move to 2550 Hz the power drops to 66 watts . Every 50 Hz higher the power drops more and more , at 2900 Hz is zero power . My RX BW is 5KHz and my TX mode is DIGU . The power slider to the far right in WSJT is up all the way .. I've tested this on 2 bands with same results ! I've used FT8 with the Flex for the past 4 months but don't remember if I've been above 2500 Hz in the past ... What am I missing here 
Thanks Ed N5DG
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Ed N5DG

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Posted 2 weeks ago

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John - AI4FR

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WSJT-X = File then settings then radio then FAKE IT. And you should be good to go. Change it to none on 60m.
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Craig - KØCF

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You need to move your transmit bandwidth up to about 3.0 kHz upper cut-off, and probably 100 Hz on the low frequency side.

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Mark - W3II

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I set my DIGU BW to 0 - 3500
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John - AI4FR

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I set mine at 100 to 3000 except for 60m. If I see possible signals above or below, I'll make adjustments. But it is very rare that I need to do so. I suspect this will change in the future as more folks get on FT8.
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Ed N5DG

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Thank you everyone , I had no idea that DIGU used the Mic Tx Filter . I am now set to 100 - 3000 
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Dave Spencer

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As John says, make sure "fake it" is selected. This will keep the audio signal in the middle of the passband when you go into transmit. You will see the rig automatically adjust the frequency in smartsdr to keep it there.
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Bob Kozlarek

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So doesn't setting the radio to DIGU mode by pass the transmit bandwidth setting?
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George Molnar, KF2T, Elmer

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It bypasses the EQ settings, not the bandwidth limits.
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Ken - NM9P, Elmer

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Right. DigU/L bypasses TXEQ and PROC, But not bandwidth controls. It also lets you use a different RX filter slope, which lets you improve filter induced latency for faster response.
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Ken - NM9P, Elmer

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Btw, it usually isn’t necessary to use “fake-it” because there are no non linearities in the tx chain and filters, as there are in legacy/analog rigs with crystal filters.

It is, however, helpful when using extremely wide splits, and some of the features in MSK144 like auto-QSY.

Ken - NM9P
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John - AI4FR

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It's needed and does help. Simply try it and watch. Transmit at say 2950hz and watch your signal on SSDR along with the ALC meter, power out, etc. Now turn on fake it or split and you'll see the difference. There is a lot more to it than that but it is a nice visual representation.