02-12-2022, 07:17 PM
Seemed like a good idea to start a thread where people can share their favorite digital mode hot tip... I will start us off, please add your own
In WSJT-X / JDTX and other variations from the WSJT-X code platform there are many options in the settings menu that may puzzle some people. One that appears to be not well understood is on the RADIO tab of the Settings menu.
On there is an option called "Fake It" (no it is not sponsored by Donald Trump) that helps you transmit the best possible audio on any of the modes in WSJT-X. What this does when enabled, it looks at the frequency value of your TX tones, if the centre of you tones is below 1500Hz or above about 2200Hz, then the program will alter BOTH your actual on air RF frequency to a lower value and your TX tones to a higher or lower value (as appropriate) all auto-magicially, not user intervention needed.
The online help can be seen here: WSJT-X Manual
Okay I know that sounds confusing, so here is an example, say I am on 18.100 MHz FT8 with Fake-it enabled and my TX tones are at 1600 HZ (mid passband) then when I go to TX, nothing needs to be changed on the radio to ensure the 2nd harmonic of my tones is outside the 300-3000Hz TX passband of my radio so the software makes no changes.
BUT if my TX tones are down at 700Hz working a new station, then the 2nd Harmonic of my tones is now 1400Hz and would be transmitted as well as my proper tones at 700Hz Arrghh not the best look for those who see you as a strong signal.
With "Fake it" turned on, as I go to transmit, the program alters my on air RF frequency down to be 18.099 and sets my tones to be 1700Hz so they appear in the far end receivers as if I am transmitting a set of tones at 700Hz. When the transmit cycle ends the radio is commanded back to 18.100 Mhz so my receiver is back to where it should be. This change of the TX tone frequency is NOT displayed to the end user, it is all done under the hood of the software.
End result, my second harmonic or third harmonic tones are no longer in the TX passband and do not make it past the rigs SSB filters WooHoo one less thing to worry about on-air. A lot of what people think is ALC overdrive is actually 2nd harmonic tones.. Do not get me wrong there are still plenty of people overdriving radios but enabling "Fake It" could be the easy step you take to make your TX signal that little bit cleaner.
This feature was built into the software for this exact reason as the authors understood that the TX tones are never going to be 100% pure and there will ALWAYS going to be 2nd and 3rd harmonic content.
When Fake It is enabled, the green dot next to the frequency display on WSJT-X will now have an "S" in it to tell you your running 'split'
Now, some brands of rigs do not allow the TX frequency to be set after the PTT is on so you may need to check if yours is compatible with "Fake It" (Note: All Icom's do allow this to occur)
I admit I may have not done the best at explaining it but please do some of your own googling and see if there is a better explanation out there but for your own peace of mind if you can, enable this feature in your digital software and have a cleaner TX signal for no cost.
In WSJT-X / JDTX and other variations from the WSJT-X code platform there are many options in the settings menu that may puzzle some people. One that appears to be not well understood is on the RADIO tab of the Settings menu.
On there is an option called "Fake It" (no it is not sponsored by Donald Trump) that helps you transmit the best possible audio on any of the modes in WSJT-X. What this does when enabled, it looks at the frequency value of your TX tones, if the centre of you tones is below 1500Hz or above about 2200Hz, then the program will alter BOTH your actual on air RF frequency to a lower value and your TX tones to a higher or lower value (as appropriate) all auto-magicially, not user intervention needed.
The online help can be seen here: WSJT-X Manual
Okay I know that sounds confusing, so here is an example, say I am on 18.100 MHz FT8 with Fake-it enabled and my TX tones are at 1600 HZ (mid passband) then when I go to TX, nothing needs to be changed on the radio to ensure the 2nd harmonic of my tones is outside the 300-3000Hz TX passband of my radio so the software makes no changes.
BUT if my TX tones are down at 700Hz working a new station, then the 2nd Harmonic of my tones is now 1400Hz and would be transmitted as well as my proper tones at 700Hz Arrghh not the best look for those who see you as a strong signal.
With "Fake it" turned on, as I go to transmit, the program alters my on air RF frequency down to be 18.099 and sets my tones to be 1700Hz so they appear in the far end receivers as if I am transmitting a set of tones at 700Hz. When the transmit cycle ends the radio is commanded back to 18.100 Mhz so my receiver is back to where it should be. This change of the TX tone frequency is NOT displayed to the end user, it is all done under the hood of the software.
End result, my second harmonic or third harmonic tones are no longer in the TX passband and do not make it past the rigs SSB filters WooHoo one less thing to worry about on-air. A lot of what people think is ALC overdrive is actually 2nd harmonic tones.. Do not get me wrong there are still plenty of people overdriving radios but enabling "Fake It" could be the easy step you take to make your TX signal that little bit cleaner.
This feature was built into the software for this exact reason as the authors understood that the TX tones are never going to be 100% pure and there will ALWAYS going to be 2nd and 3rd harmonic content.
When Fake It is enabled, the green dot next to the frequency display on WSJT-X will now have an "S" in it to tell you your running 'split'
Now, some brands of rigs do not allow the TX frequency to be set after the PTT is on so you may need to check if yours is compatible with "Fake It" (Note: All Icom's do allow this to occur)
I admit I may have not done the best at explaining it but please do some of your own googling and see if there is a better explanation out there but for your own peace of mind if you can, enable this feature in your digital software and have a cleaner TX signal for no cost.
Peter Sumner, vk5pj
You have enemies? Good. That means you've stood up for something, sometime in your life.
- Winston Churchill
You have enemies? Good. That means you've stood up for something, sometime in your life.
- Winston Churchill