1.3 Level Meter miscalibrated for DAX?

Bob N7ZO

When using audio from DAX, I cannot get the set RF power until the main level meter bar (on the SmartSDR "P/CW" panel) is all the way up to zero and the peak indicator shows way into clipping.  This is new behavior to 1.3.0.

In this particular case, I am using the Tune signal from WSJT-X, which is just a sinewave (1307Hz for my current WSJT-X setting, but the problem does not seem to be dependent on frequency ).

The frequency is 50.276MHz and RF power is set to 50W and I need to bring the level up as shown to get 50W:


If I set the level as recommended (manual section 25.3.3) I get 17W:

David Decoons, wo2x

I too am seeing very poor drive with DAX enabled.

On RTTY this morning trying to work Viet Nam and couldn't get good drive. Reverted back to 1.2.17 and normal output.

Dave, wo2x

DK1EY

Same here with PSK via DIGU!

Tim - W4TME

Bob - can you provide a screen shot of your DAX Control panel so I can get a complete look at your setup?

Al K0VM

I have seen a problem with DAX and SSB drive levels related to the use of profiles..
May I suggest that after you use a profile to set a digital profile that you either toggle the mode to usb and then back to DIGU/U  or  deselect and then reselect TX for the slice.

If you have not used a profile, You may find that toggling the TX to something differentt and then back will restore the TX power output for DAX

AL, K0VM

Bob N7ZO

Tim, as requested (captured during transmission):

Bob N7ZO

Hi Al,
Yes, I have noticed some oddities directly after loading a profile that requires toggling modes and TX to clear up, but I have not been able to characterize them yet.  The results I am demonstrating here are after the toggles to get things working mostly correctly.

Tim - W4TME

Thanks.  I am looking into this

Tim - W4TME

What is the level of your digital mode source?  

I am using Fldigi that is putting out 0 db of signal on transmit in PSK31 mode.  In this configuration with the DAX Control panel TX input set at 51, the level meter in both DAX and on the SmartSDR console shows it almost hitting 0 dB.  At these levels I am putting out 95W peak into a dummy load.  The power was measured by a PowerMaster wattmeter.

I think your audio source gain level may be too low.

Bob N7ZO

Tim,
This is the same WSJT-X program and same WSJT-X settings as I have been using successfully with earlier releases of SmartSDR.  I have my DAX transmit gain set to 41 and, as you can see, I am getting full scale metering on the DAX panel and full scale metering on the SmartSDR panel.

I'm not sure what you mean by "your audio source gain level may be too low".

David Decoons, wo2x

Hi Tim,

I am using DM780 which is set to 0 dB  out. TX level on DAX channel 2 tx is 44 which gives peak indicator in SmartSDR just under zero (any higher and it would turn red on peaks). Power in SmartSDR set to 45 and only get 15 watts out.

Same exact settings in SSDR 1.2.17 gives 43 watts out.

I've just completed loading a clean OS image into my test PC and going to install SSDR 1.3 with DAX and CAT clean, no prior versions installed. Will see what the results are...

Dave, wo2x

Al K0VM

What I have seen is that the Power Output is lower, relative to the level meter immediately after booting the radio into a persisted DIGI mode and it remains low until a TX profile is toggled....

Output can also become low following a change of mode  i.e. DIGU>USB>DIGU... again toggling through a different TX profile will correct

AL, K0VM

Bob N7ZO

Following Al's suggestion, I started playing around with changing the TX profile.  Now I think I have arrived at a second incorrect state.  With the output set to 50W, I am now getting 36W and strangely, the Compression meter is showing compression even though I am in DIGU mode with DAX audio selected:




BTW, I am measuring my output power with a trusted LP-100A meter that usually agrees with SMartSDR's power output setting (although I find SmartSDR's RF power meter a bit optimistic).

LATE INFORMATION:  From the above state, if I toggle the Slice's mode to USB and then back to DIGU, I am back to 17W, but the Compression meter no longer shows any compression.



I am not making any changes to WSJT-X or the DAX panel.

Al K0VM

Bob,  Here is a screen shot of how mine runs ( normal )
Signal is from WSJT-X with its Pwr slider set at mid scale, DAX slider is set at default (44)

Not sure what the difference is..  I have a 6500 .. If you have not already done so, export you profiles and do a persistence reset, import your profiles. 
At this point the output may be low, toggle to a different profile and back again.

AL, K0VM

W8TZ Ross

Same issue here when trying to run WSJT-X. Very low power output. The problem seems to be related to DIGU mode.

Al K0VM

Ross,
  A work around  ( maybe ).  If you have not already done so, save a TX profile of you current digital ( WSJT) operation state.  Select some other TX profile and then reselect your digital (wsjt) TX profile.  Might restore your wsjt output power..

AL, K0VM

W8TZ Ross

Thanks for the info Al. I will try that and see what happens. I have not had much time to play with yet.

Steve - M3SXA

Followed the work around above from Al that appeared to do the trick.... using my 6500 and HRD tnx's...

Tim - W4TME

There is something going on with the transmit levels.  We have a defect listed for it and are actively investigating it.

Steve - M3SXA

Thanks Tim.....

Steve - M3SXA

Just an observation I have to be careful cos limited to 10 watts, but not realised the power level was wound right up on one band and my digital display on my power master showed 110 watts on my 6500!!!!!

Bob N7ZO

Hi Al,

Thanks for the suggestions, but none seem to help here.  And I did the persistence reset before I realized it wiped out all my profiles. (grrr...)  Now I use import and export.