HOT TX on WSJT-x

mark1161
Posts: 49
Joined: Sun Apr 09, 2017 4:16 pm

HOT TX on WSJT-x

Postby mark1161 » Sat Aug 04, 2018 4:17 pm

Good Afternoon All,

I have Thetis ANAN 100D and I see, on the waterfall, that TX signal, in WSJT-x, s pink and very wide. No matter how high or low I adjust TX Gain the signal is not changing in apparent bandwidth. I am using about 35 watts of power. What should I be looking a to correct the problem.

Thanks

Mark
WA2DIY
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w-u-2-o
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Joined: Fri Mar 10, 2017 1:47 pm

Re: HOT TX on WSJT-x

Postby w-u-2-o » Sat Aug 04, 2018 5:47 pm

First: ensure that all sample rates everywhere are 48KHz. Mostly this means going into the Windows sound control panel and changing any VAC related devices to 48KHz. If using VMB, be sure to go into the separate VMB control panels (find them in the VMB folder in the start menu) and set them to 48KHz. You will have to reboot if using VMB.

Second: set your VAC TX gain to 0dB. Set the "Pwr" settting in WSJT-X so that you are achieving -1dB ALC indication. Set your RF Drive in PowerSDR to achieve the amount of output power you want using "Tune" in WSJT-X.

With that complete everything will be perfect regardless of what it looks like on the panadapter/waterfall (unless you see some really weird harmonics, in which case go back to step 1, ensuring everything is 48KHz).

Third: tweak your display parameters until you are happy, see here -- https://apache-labs.com/community/viewtopic.php?f=6&t=2545
mark1161
Posts: 49
Joined: Sun Apr 09, 2017 4:16 pm

Re: HOT TX on WSJT-x

Postby mark1161 » Sun Aug 05, 2018 1:53 am

Scott,

These are the best Display settings I have had since I got the radio 2 years ago. Primarily a digital mode user at home so I am very familiar with how the radio behaves with these operations. And, these settings have really seem to have given new life to the rig. I know your mantra of setting everything to 48K so that was done already but I never got into the DSP config before. Now, the display has improved on TX. I no longer am getting the wide pink blob in the Waterfall. I am still seeing a very narrow pink line but the waterfall is now faster and the grid is tighter with a spiked signal in the panadapter. Looks good. Again, this is the Thetis rig. The PowerSDR rig is displaying what I would call a normal signal very narrow signal pattern in the waterfall. I am still, however, going to update those settings with your suggestions.

Thanks again.

Mark
WA2DIY
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w-u-2-o
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Joined: Fri Mar 10, 2017 1:47 pm

Re: HOT TX on WSJT-x

Postby w-u-2-o » Sun Aug 05, 2018 2:53 am

:)

Thetis does not have the ability to adjust the waterfall dynamic range in TX like PowerSDR does...yet. So what you are seeing is just an artifact of the display in Thetis and is not indicative of bad signal quality during transmit.

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