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Inconsistent power output;WSJT-X v2.1.0; Flex 6400 w/atu; SDR v3.0.27

dave
dave Member
edited June 2020 in SmartSDR for Windows
When operating in FT4/FT8 cannot transmit at full power.


When transmitting above 60 w, the output will not get beyond ~70w.  I have checked this to my dummy load and it is consistent.


My settings: ATU on; SWR 1.2
DIGU mode; 3.0k filter
All signal processing off.
DAX on.

DAX control window: TX Gain 50%
RX stream Slice "A", 50%

CAT control window
WSJT-X my port 5003
WSJT-X PTT
COM4

Please let me know if this is a common experience or if I am missing something.


Answers

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin
    edited August 2019
    I've only been operating on 6M lately, but that would be consistent with what I have seen.  

    I haven't worried too much about it, but I suspect that my voltage on the back of the radio is sagging a bit.  

    If you can crank your power supply up to 15V that will help.

    Mike va3mw
  • KL4QG
    KL4QG Member ✭✭
    edited May 2020
    What is max wattage on flex 6400M on SSB/CW /Diq/FM /AM
  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin
    edited August 2019
    100 watts PEP SSB
    100 watts CW FM
    25 watts AM

    Digital is part of SSB
  • KL4QG
    KL4QG Member ✭✭
    edited August 2019
    Coolest
  • AH0U
    AH0U Member
    edited August 2019
    Where is the power slider on the WSJT software set???? Set it at max
  • bahillen
    bahillen Member ✭✭✭
    edited August 2019
    Audio response can affect power output on ft8 and ft4. Check with audio tx at 1500, center of band. Audio Tx EQ can make a difference. And audio bar on SmartSDR TX applet should be just below the red as controlled by the DAX slider. Your computer audio level on the sound record maybe turned back looking at the properties. Just some ideas. When I have had these kinds of audio level problems it is very frustrating to work your way through it. Making a written checklist of things that caused issues helps cover up for my confusion factors and forgetting past things to check. 73 Bill
  • dave
    dave Member
    edited August 2019

    Yes, 100%.  Normally, I transmit at ~55w; but, when trying to hit some far DX, I jump it up somewhat.  FT4/FT8 is "weak signal" but one still has to overcome the receiving stations local noise floor.
  • dave
    dave Member
    edited August 2019

    I have been hesitant to adjust the TX audio gain while in DIGU; while I am certain the applet is right, I'm not sure that my tweaking won't splatter the signal and cause distortion.  This might improve the power, as seen from the indicated output wattage, but decrease the readability.  I'm just spitballing here - don't know if this correct or not; but I will mess it in a logical and repeatable way.
  • dave
    dave Member
    edited August 2019

    This would make sense and my power supply is adjustable.  Next time I see it happening, I will (mal) adjust the PS output from 13.8 to 15vdc for testing. 
  • Michael N3LI
    Michael N3LI Member ✭✭
    edited August 2019
    What do you have your streaming TX set at?
  • Michael N3LI
    Michael N3LI Member ✭✭
    edited August 2019
    The Flex is much less likely to spew bad signals than legacy radios. I'd move the TX Streaming level up until you get the output you would like.  If your Audio meter is at around the right level (remember red is dead) you should be good to go.
  • Bob G   W1GLV
    Bob G W1GLV Member ✭✭
    edited June 2020
    Power output can be erratic if you try to transmit on the edge of the TX passband. The transmitter will try to reduce the power out. 
  • Larry _ NY8T
    Larry _ NY8T Member ✭✭✭
    edited August 2019
    I get full output and clean FT4 and FT8 Signals with my level meter just below 0 db on the level meter. This is with my TX Stream level set at 47.


  • Michael N3LI
    Michael N3LI Member ✭✭
    edited August 2019
    I keep mine at -10, but I think your levels are FB as well.
  • dave
    dave Member
    edited August 2019

    50% on the slider
  • dave
    dave Member
    edited August 2019

    I'm peaking just shy of the "red zone".
  • dave
    dave Member
    edited August 2019

    Your pic looks identical to my output level throughout my transmitting power (~50 - 70 watts); but I get no higher than ~70 even when I have firewalled the TX power on both the Flex and WSJT screens.
  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin
    edited August 2019
    Hi All

    The audio setup is the same as discussed in Section 25 for voice peaks.

    Mike 

    When setting up your microphone audio for optimal modulation, adjust the input gain so that the peak level indicator is peaking just BELOW the 0 dB on voice peaks.

    It is very important that your peak level indicator never exceed 0 dB and turn red at any time. A red peak level indicator indicates over-driven or “clipped” input audio levels resulting in audio distortion.

    The input ALC is active, but excessive input signal levels may result in input signals that can exceed 0 dB. If you see the peak level indicator turn red at any time, turn down the audio input level until you no longer see the peak level indicator turn read.


  • Michael N3LI
    Michael N3LI Member ✭✭
    edited August 2019
    What I would suggest is getting a good dummy load, and try switching bands to see if the power remains consistent or not. I'll bet it does.
  • Patrick
    Patrick Member ✭✭✭
    edited June 2020
    Some thoughts on setting the audio gain. DAX TX setting, I set this to -10 to -5 and leave it there. I use wsjt-x at this point to set the overall gain as represented on the audio gain meter in the control panel, setting it, as described by others , so that the peaks are just below red. I use the wsjt-x slider as my primary setting because it has the best accessibility. Please note that slider position is remembered by wsjt-x in both the TUNE and ENABLE button settings independently. Use tune first, Enable will be close to that setting. It also remembers it on a per band (frequency) and mode (FT8, FT4 and JS8Call), so once set it will be remembered.

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