poor transmissions #wsjt-x


KD7YZ Bob
 

I finally bought an RSPDuo SDRPlay.
So I can't decide if I have settings wrong or I am seeing ringing; distortion, on FT8 Signals this week.

A few stations, hardly "ALL" though, cause intense, for want of a better word, 'Splatter' on my WF screen.
It is apparent in the screenshot.

Can I be causing this by my lack of understanding? Or is this 3, 5th harmonics, images or whatever?

In any case, if it is my fault or others, is my ability to decode weaker stations impacted ?

WSJTx 250.2 is what I am using and the RSPDuo feeds the audio.

To repeat, are my settings causing the program to NOT decode some stations which may be underneath all the 'ringing' ?
If so, what do I do?

thank you.



--
Bob KD7YZ in NE Kentucky


 

Hi Bob,

 

I assume this is Windows. Have you checked the audio levels: out of SDRUno, through the virtual audio cable to WSJT-X. Though it looks more like 120 Hz modulation on the signal. I had a problem on transmit signals with 100 Hz modulation from 3 walwart cables trailing among the DC cables to the rig. What’s the coax like from the PC to the RSPDuo?

 

Otherwise I wouldn’t know how 120 Hz modulation could get into what is wholly a digital audio chain.

 

73 Phil GM3ZZA

 

Sent from Mail for Windows 10

 

From: KD7YZ Bob
Sent: 03 July 2021 14:16
To: main@WSJTX.groups.io
Subject: [WSJTX] poor transmissions #wsjt-x

 

I finally bought an RSPDuo SDRPlay.

So I can't decide if I have settings wrong or I am seeing ringing; distortion, on FT8 Signals this week.

 

A few stations, hardly "ALL" though, cause intense, for want of a better word, 'Splatter' on my WF screen.

It is apparent in the screenshot.

 

Can I be causing this by my lack of understanding? Or is this 3, 5th harmonics, images or whatever?

 

In any case, if it is my fault or others, is my ability to decode weaker stations impacted ?

 

WSJTx 250.2 is what I am using and the RSPDuo feeds the audio.

 

To repeat, are my settings causing the program to NOT decode some stations which may be underneath all the 'ringing' ?

If so, what do I do?

 

thank you.

 

 

 

--

Bob KD7YZ in NE Kentucky

 


--
73 Phil GM3ZZA


Bill Somerville
 

On 03/07/2021 13:29, KD7YZ Bob wrote:
I finally bought an RSPDuo SDRPlay.
So I can't decide if I have settings wrong or I am seeing ringing; distortion, on FT8 Signals this week.

A few stations, hardly "ALL" though, cause intense, for want of a better word, 'Splatter' on my WF screen.
It is apparent in the screenshot.

Can I be causing this by my lack of understanding? Or is this 3, 5th harmonics, images or whatever?

In any case, if it is my fault or others, is my ability to decode weaker stations impacted ?

WSJTx 250.2 is what I am using and the RSPDuo feeds the audio.

To repeat, are my settings causing the program to NOT decode some stations which may be underneath all the 'ringing' ?
If so, what do I do?

thank you.



--
Bob KD7YZ in NE Kentucky
Hi Bob,

that can happen if you enable one of the SDRuno noise blankers and there are strong signals in, or near to, the Rx passband. Try adjusting the NB level, using the other ND, or switch off the NB altogether.

73
Bill
G4WJS.


KD7YZ Bob
 

Hello Bill:
The NB, as it is now, wasn't activated. I believe it was still NBOFF as I usually leave it.

The "next" time I see received signals like that, I will screenshot the UNO settings/faces as well.


--
--
Bob KD7YZ in NE Kentucky


KD7YZ Bob
 

Hello Philip,
What I observed then isn't happening now. And it doesn't occur all the time. At the moment, 6m Band dead here in KY and the WF has but one lad calling CQ. He's a -11. Signal looks fine.

No other changes here since AM that I know of


--
--
Bob KD7YZ in NE Kentucky


Jim Brown
 

On 7/3/2021 5:29 AM, KD7YZ Bob wrote:
To repeat, are my settings causing the program to NOT decode some stations which may be underneath all the 'ringing' ?
Overload anywhere the signal is audio will generate harmonics and intermod. This can happen between the detector in your radio and the WSJT-X decoder, and between the other station's WSJT-X and his SSB modulator. If you're seeing it mostly the strongest signals, it's on your end; if on signals that are not the strongest, it's them.

The setting of the output level from the radio can be too high, the input gain of the computer can be too low or too high. On the TX side, the output level of the computer can be too high, and the input gain of the rig can be too high or too low.

I mostly use WSJT-X on 6M and 160M, and I rarely see dirty signals. I recently did help a neighbor clean up his signal; he was using an SPE 1K amp to run about 300W, and had the amp set for Low Voltage. His sidebands were full of noise, and only about 35 dB down. He switched to high voltage, and sidebands dropped by about 6 dB.

A few hours later, I looked at another neighbor, N5KO, running a IC7300 and KPA1500; his sidebands were 50 dB down, and clearly defined the same width as the signal and spaced 300 Hz from it; second set were about 6 dB below that.

73, Jim K9YC