FT8 Transmission Level

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Hello, I have a Flex 6600. What is the ideal or optimal transmission LEVEL when transmitting on FT8 ?

I notice there is a LEVEL meter on the right hand side of SmartSDR and just above COMPRESSION, that goes from -40dB (Left) to 0 (Right in red), and when I transmit I get a full color line and at the end of this line to the right I small square marker in the same color of the color line.

Some one told me in -10 in yellow/green color and the solid square in between -10 and 0.
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Juan TG9AJR

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Posted 3 months ago

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KY6LA - Howard, Elmer

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Simple Answers--- It Depends

1.  NEVER let it go into the RED

2.  If you are running barefoot (100W or less) then a bit of yellow will not degrade your XMT signal
much


3.  If you are using an AMP (100W++) then avoid letting it go into the yellow as you do not want to be amplifying distortion products.
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Juan TG9AJR

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OK thank you Howard.

And if I may ask what is the proper way to adjust that LEVEL ?
Using the DAX TX Gain and/or the Adjust TX Audio Level (PWR) the vertical slide on JTDX/WSJT-X ?
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KY6LA - Howard, Elmer

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FT8 is a WEAK SIGNAL MODE NOT A LOW POWER MODE.

That said use only the power your need to use to make the contact.


if the other station is weak.. say -22 or less then it is likely you will need to use power for him to hear you


ALSO... with Flex DAX your decoding is entirely in the Digital Chain vs external boxes such as Rigblaster that do A/D and D/A conversions.. so it is likely you will have a 3-6 dB gain advantage over the other guy..  This means that if you are hearing him at say-18 then it is likely given equivalent antennas and power that you are being heard at -18-6=-24  - hence you need power for him to overcome his equipment deficiencies so that he can hear you.
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KY6LA - Howard, Elmer

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I use DAX TX gain to control levels
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Neal Pollack, N6YFM

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Juan:    YES :-)

Adjusting any of;

+ DAX TX level slider
+ WSJT-X Power Slider
+ Windows Playback Device Levels Tab

will all affect this SSDR Flex TX level.
For personal preferrence and no real scientific reason, I tend to
make sure that the windows level tab slider is not set above 80%,
and also that the WSJT-X power slider is set around/approx 80%,
then I use the DAX TX level slider to do the final level adjustment.
This is one of more than a dozen ways to properly adjust the level.
Whatever you choose, just don't let the peaks go over the 0 dB level
on the Flex SSDR or Maestro interface.

Cheers,

Neal
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Ned K1NJ

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   Weak signal modes are used to -hear and decode- weak signals, not
necessarily to transmit them.  For example:  EME, moonbounce, might
best use a "weak signal mode", but it still would take considerable power
from your antenna to make the trip.
                                 Ned,  K1NJ