WXTOIMG decode looks scrambled

[tratzum]

I am having issue with WXTOIMG. Most times the live decode img looks scrambled. I have tried the slant correction but most of the time the img is so messed up there is nothing I know how to do. I know I can get a good clean signal when I just listen to the pass with my speakers but for whatever reason WXTOIMG is not working right.
I am using a RTL-SDR blog v3, SDR console vb audio cable.
Any help or tips would be great.

 

[Freemor]

That is certainly not what it should be. I'd suggest carefully working through the "Required Calibration" section under help. I never got good results until I did. Also check that your rception options are correct NFM, bandwidth 40KHZ, no filters (unless you have a NOAA APT filter), no Squelch.

From how white that is it looks like you volume may be to high. Again the Calibration section covers that.

Hope that helps

 

[tratzum]

Thanks for the reply. I will go over calibration section again. I have thought that the volume may be a bit high but during a record the bar is green and around 69.
Aside from trying to recalibrate do you think there could be an issue with VB audio from SDR consolev3 to WXTOIMG. I read audio latency could cause some issues. I know very little about audio tech.

 

[Freemor]

If the volume indicator in xwxtoimg is greem you're probably ok and 69 definitely doesn't sound too high.
It might be the VB audio. I do not have direct experience with windows virtual audio cables but under linux if I use snd_aloop (basically the linux equiv of a virtual cable) I'll get sudden jumps part way through the capture. So when doing wxtoimg I just use a physical audio cable. (small cable with a 3.5mm male jack at both ends. one end goes into the headphone jack the other into the mic jack). I always get the best results with the physical audio patch cable. But I've definitely seen others have good results with virtual cables.

if you have a patch cable handy I'd definitely give that a try

 

[Freemor]

As you are just starting and trying to get good pulls from the satellites I should mention that there are times when the Satellite switches instruments part way through a capture which can look like some sort of an error to new eyes. I find that happens mostly on early morning or late evening passes. The patterns on the varying grey level bands encode what instrument is active. So if the paterns on those change right when there is an abrupt change in the image it the satellite not you.

 

[ArloG]

IF bandwidth should be 42 kHz for strong signals. You can lower it a bit for weak passes to reduce noise.
Audio levels in the high 40's to mid 50's work well. That's displayed in the lower right of the window.
You can record the passes and play them back with manual record. Helps for tweaking.
Look at the soundcard settings. Sometimes issues like yours can be attributed to too high of a sampling rate.
To weed out that try setting VB Cable sampling rate to 11025 and see what happens.
If you look in the wxtoimg soundcard settings it should be the same. Later on when you get good copies you can play with them.
VB might like the audio level a bit below 90 or so to prevent saturation.
There have been a few times I've had to completely uninstall VB Cable and wxtimg and cold boot the pc and reinstall it all.
For some reason it straightened up.

 

[tratzum]

Attached is one of my most recent decodes. At the Top where it looks scrambled SDR console was on and auto tracking with VB cable going to WXTOIMG. Where the picture clears up is where I selected my speakers on SDR console waited a few sec and selected VB cable.
Not sure why it clears up after basically stopping WXTOIMG from getting audio and turning it back on. The raw image for this past is also very very dark.

 

[Freemor]

Interesting. wxtoimg saves a wav file of what it recieved. maybe listening to that wav file might give you some clues.The middle part (othe than the little jog in the middle of it) looks pretty right on. it'd be helpful to the the -pris versions of any future captures as those are what it got before any port processing was applied. Is xwxtoimg set to get audio from the VB cable or is it pulling from the sound card. if the latter it'd explain this behaviour as the sound would come out the speakers and be picked up by the microphone. Basically an audio loop with no cable.

 

[tratzum]

Interesting. wxtoimg saves a wav file of what it recieved. maybe listening to that wav file might give you some clues.The middle part (othe than the little jog in the middle of it) looks pretty right on. it'd be helpful to the the -pris versions of any future captures as those are what it got before any port processing was applied. Is xwxtoimg set to get audio from the VB cable or is it pulling from the sound card. if the latter it'd explain this behaviour as the sound would come out the speakers and be picked up by the microphone. Basically an audio loop with no cable.

I appreciate the reply's and the assistance. I went ahead and setup SDR# and Gpredict to get my auto capture working and everything seems to work. Had to use my old Vdipole at the house since my QFH is on the roof at work. No issues on any of the decodes with Gpredict-SDR#-VB audio cable- WXTOIMG.

For what ever reason with SDR Console V3 in auto satellite track mode WXTOIMG doesn't decode right. SDR Console V3 worked great if I manually switch audio output to speakers and then back to VB cable during a pass but leaving VB cable on does not work.

 

[Freemor]

Well that looking darn near perfect. Perhaps SDR Console V3 is doing something weird like trying to do pitch correction in auto satellite tracking mode. I don't know SDRconsole so couldn't say. With my discone antenna I have no need to track the satellite. Just make sure the SDR software is tunned to the right satellite at the time of the pass. The pass list in xwxtoimg will show when sattelites are due to pass if you've set your location and updated your keplers (which from earlier posts it looks like you have)

 

[tratzum]

As a follow up and make the issued resolved I have identified and fixed my issues.
It was 2 issues. I should have known better. I spent 20 years in the Army working with RF and electronics and I always preached. CCC. Cables, connections and antennas.
I noticed that when one of my coworkers moved the SDR dongle the noise floor went nuts.
1. The biggies issue was the SMA connector on the RTL-SDR dongle was loose. After tightening the nut on it the noise floor /SDR dongle was less touchy.
2. Replacing my 50ft of RG58 with a shorter length with soldered connectors made it behave well even if handling the SDR dongle
3. re-do slant correction
No issues for 6 days now very clear minimal static on images.

 

[Wolfy007]

I am having issue with WXTOIMG. Most times the live decode img looks scrambled. I have tried the slant correction but most of the time the img is so messed up there is nothing I know how to do. I know I can get a good clean signal when I just listen to the pass with my speakers but for whatever reason WXTOIMG is not working right.
I am using a RTL-SDR blog v3, SDR console vb audio cable.
Any help or tips would be great.

I get that too. Its the SDRUno software version. All v 1.42.xxx do something with the audio.
I went back to v 1.41.1 and it is perfect now. Both VAC and VB cable work well with the older version and set with default settings. The latest version of SDRUno v 1..41.1128 has poor over load issues when using an LNA. Even on FM Broadcast Band its a shocker. I have teh SDRplay RSPdx and decodeing NOAA with SATDUMP or the older version of SDRUno works fine.

 

[Wolfy007]

I get that too. Its the SDRUno software version. All v 1.42.xxx do something with the audio.
I went back to v 1.41.1 and it is perfect now. Both VAC and VB cable work well with the older version and set with default settings. The latest version of SDRUno v 1..41.1128 has poor over load issues when using an LNA. Even on FM Broadcast Band its a shocker. I have teh SDRplay RSPdx and decodeing NOAA with SATDUMP or the older version of SDRUno works fine.

Attached is one of my most recent decodes. At the Top where it looks scrambled SDR console was on and auto tracking with VB cable going to WXTOIMG. Where the picture clears up is where I selected my speakers on SDR console waited a few sec and selected VB cable.
Not sure why it clears up after basically stopping WXTOIMG from getting audio and turning it back on. The raw image for this past is also very very dark.

Its SDR SOftware issue. Use an older version. I use SDRUno v 1.41.1 Later versions being v1.42.xxx give that effect. Satdump works well too with SDRPlay RSPdx. I dont know what the issue is but I use exactly the same settings between later versions and v1.41.1

 

[tommytomato]

I'm having the same issues, over the past week been getting great image NO issues at then all of a suddon they are all screwed up
view my page image here images recorded I'm using SDRplay and VB cable and SDR console v3.3

 

[Wolfy007]

I'm having the same issues, over the past week been getting great image NO issues at then all of a suddon they are all screwed up
view my page image here images recorded I'm using SDRplay and VB cable and SDR console v3.3

I would download SDRUno v 1.41.1 and you will have no more issues with WxtoImg. SDRUno team say no audio changes were made to the various versions on Uno from 1.41 to 1.42. However the API version has changed. I have also used Satdump, it replies on Uno's API to find the SDRdx I have. Even Satdump has problems receiving APT when I have any version of SDRUno 1.42.xxxx installed. Uninstalling 1.42.xxxx and installing 1.41.1 (Lower version API) and all is fine. Maybe the latter version of the API don't like my audio side of the motherboard, thoug it does the same with any virtual audio driver to as well as a hardwired audio loopback Line in to Line out.

 

[tommytomato]

Wolfy007
I got it going again by uninstalling VB cable and installing the VB Vac version on trial so far so good, I do SDRUno install, I'm still quiet new to all this, once I have done my site I will get onto watchinh some vids about SDRUno Weather Satellite Images for Peth, Australia still working on site when I can but week one was the fresh upload this morning using the VB Vac software.