locked Re: What should Radio TX Power Setting really be? #wsjt-x #WSJTX_config


Because people will complain if they can’t adjust the output of WSJT-X. But seriously, you need to balance the audio levels, get as high an audio level as you can get to the radio without adding excessive quantisation noise. To me, this means generating the digital version using as many bits as it can, and then converting to analogue as high as the radio accepts. In the case of a USB Audio Codec radio like the IC-7300, this means keeping the digital signal as unprocessed as possible between WSJT-X and the radio – I am presuming having 0 dB attenuation in the Windows mixer means it’s not processed. I hope that my PC does not perform a DAC/ADC conversion when using a USB Audio Codec.


Then you need to rely on the volume control (again digital) in  the radio not to add too much noise. I have mine set to 25% which I hope just lops the two LS bits off the digital value of the audio.


As I said before I then have the Power drive set to 50% and get 36 W out of the radio. Any more than that and I will probably be non-compliant with Ofcom guidelines on public RF exposure.


73 Phil GM3ZZA


Sent from Mail for Windows 10


From: Bob McGraw - K4TAX
Sent: 24 July 2021 18:11
To: main@WSJTX.groups.io
Subject: Re: [WSJTX] What should Radio TX Power Setting really be? #wsjt-x #WSJTX_config #wsjt-x #radio


That being the case, then why is the PWR slider in the WSJT-X application available for use in both the TUNE and TRANSMIT mode and why does the application allow for saving those settings?

Thus if the PWR slider is set to a maximum of 0 dB, then the computer sound level must be reduced to a much lower level.  And/or the Line gain of the transceiver be reduced to a much lower level.   In these instances, the granularity of the adjustments becomes significant steps in terms of level adjustments. 

Guess I don't understand your point and thinking. 

Bob, K4TAX

On Sat, Jul 24, 2021 at 07:47 AM, David Fanelli wrote:

First, set the "Pwr" slider on the Human/Machine Interface (HMI) to 0dB and never touch it. There are two reasons to keep the audio output of WSJT-X at full power. The first is that you need sufficient drive to activate the VOX of either the RIGblaster or Signalink. The second is quantization noise. Running the audio at full output reduces quantization noise.


73 Phil GM3ZZA

Join main@WSJTX.groups.io to automatically receive all group messages.