eHam

eHam Forums => CW => Topic started by: AG1LE on December 24, 2013, 07:01:55 PM



Title: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on December 24, 2013, 07:01:55 PM
I have been working on a new Bayesian Morse decoder for FLDIGI for a while.
The goal was to have a CW decoder that adapts better to different operators rhytms, sudden speed changes, signal fluctuations and noise and still is able to decode Morse code fairly accurately.

While this software is not perfect and has some bugs I am happy to release this brand new version for alpha testing.  I finished the software integration to FLDIGI v3.21.75 and spent few hours today listening bands.  Below is a small example of W1AW code bulletin at 3.58105 MHz  received with KX3 and a side by side comparison of legacy CW decoder  vs  Bayesian decoder:
http://ag1le.blogspot.com/2013/12/new-morse-decoder-part-2.html (http://ag1le.blogspot.com/2013/12/new-morse-decoder-part-2.html)

Legacy  vs. Bayesian decoder side by side:
(http://4.bp.blogspot.com/-d1pS2XAsxeA/Uro1DR6-ghI/AAAAAAAAFbI/yN9D--Uud28/s1600/WP_20131224_20_07_39_Pro.jpg)

The full source code is available in here: http://www.w1hkj.com/ag1le (http://www.w1hkj.com/ag1le)

I would like to get some alpha testers who are not afraid of compiling this code from sources,  playing with it, breaking it and hopefully also helping me to find the bugs. For example  - the noise level estimator (noise.c) needs some serious work.  If you have a algorithm that does the job better this would be one place to start improving.  Also, if you know Viterbi or Kalman filter algorithms like your pockets I would like to get help fixing a bug that appears in posterior probability calculations in probp.c occasionally.

Anyways,  happy holidays for all FLDIGI users and hope to work you over the radio.

73
Mauri AG1LE


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on December 24, 2013, 09:50:04 PM
Looks very interesting. I'd like to play with it on this Xubuntu machine.

Although I just compiled tlf logger from source a couple weeks ago, this source wouldn't configure. Looks like I need to install some packages first. Another day though; it's bedtime here. :-)


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on December 25, 2013, 02:06:47 PM
Looks very interesting. I'd like to play with it on this Xubuntu machine.

Although I just compiled tlf logger from source a couple weeks ago, this source wouldn't configure. Looks like I need to install some packages first. Another day though; it's bedtime here. :-)
Thanks Mike

I am using Linux Mint 15 as my development environment. What packages are missing on your system?
Once you get this compiled let me know if you have trouble getting the decoder working. 

It seems to work better at lower signal levels - I can provide some test WAV files if you don't have radio interface to your Xubuntu machine.


73
Mauri AG1LE


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on December 25, 2013, 02:45:39 PM
Hi Mauri,

I installed all the missing packages. It's compiling right now. I'll keep you posted.

I have had fldigi 3.21.38 installed and working for some time. I shouldn't need any .wav files.

I will tell you that I am no C expert. I used to code a lot in Pascal, but that's been years ago. Never wrote anything in C.


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on December 25, 2013, 03:10:13 PM
Ok, I have it compiled and running. :-)

I think I need to change some things in the configuration. It decodes CW, but when I check the Bayes decoding, it doesn't copy CW as well. The version I had copied CW better. I was temped to change the configuration, but I don't have much more time to play with it this week. If you could suggest how best to configure it, I'll try it again.

I see the old fldigi version has the Bayes decoding box. I didn't see that before. I don't have it checked.

EDIT: I see the Help > About in both versions shows v. 3.21.75. Oops. I shouldn't have installed the new version where I did. The config is still different in both versions; I don't know what's going on.

I could post or e-mail the config files or a screenshot. Let me know what you suggest or need.


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on December 25, 2013, 06:05:52 PM
I played with it a little more. It does not copy CW correctly at all when Bayes is checked. Unchecking it, it copies CW very well.

I tried turning the volume down as you suggested, and no change.

Perhaps if I changed the configuration?


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on December 25, 2013, 06:32:17 PM
I played with it a little more. It does not copy CW correctly at all when Bayes is checked. Unchecking it, it copies CW very well.

I tried turning the volume down as you suggested, and no change.

Perhaps if I changed the configuration?

Mike

Can you verify that before you switch on Bayesian decoder you have Configure / Modems / CW / General / "Matched Filter" checked and  "FFT Filter" not checked?
Also, please  check "Tracking" on.   After this is verified please click "Bayesian decoder"  on and observe  lower left corner.  If you see "CW Rx  NN"  where speed NN is changing rapidly then the new decoder is working.  As mentioned this version is still very sensitive to volume and signal/noise level.  In my system I am adjusting KX3   RF volume (I have AGC turned off) so that CW signal is barely visible on the waterfall.

There is a bug that shows up by turning CW Rx speed indicator negative  - if you get into this situation you need to restart the application. Typically this happens when for some reason the likelihood calculations in "probp.c" exceed 1.0  which on the next few sampling rounds quickly amplify pmax to a large number.  I have not found the root cause for this bug yet, but seems to be somehow related to signal strength and SNR of the signal.  The noise power estimator "noise.c" is one suspect...not sure if this part really works.

Thanks for helping out to debug this software.

73
Mauri AG1LE

 


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on December 25, 2013, 06:50:48 PM
Can you verify that before you switch on Bayesian decoder you have Configure / Modems / CW / General / "Matched Filter" checked and  "FFT Filter" not checked?
Also, please  check "Tracking" on.   After this is verified please click "Bayesian decoder"  on and observe  lower left corner.  If you see "CW Rx  NN"  where speed NN is changing rapidly then the new decoder is working.  As mentioned this version is still very sensitive to volume and signal/noise level. ...

That worked. :-)

EDIT: Screenshot at
http://www.w0btu.com/files/misc/software/misc/
http://www.w0btu.com/files/misc/software/misc/fldigi_beta-1.png

I wonder if Nate, N0NB would enjoy helping?


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on December 26, 2013, 06:10:24 AM
Quote
That worked. :-)

EDIT: Screenshot at
http://www.w0btu.com/files/misc/software/misc/
http://www.w0btu.com/files/misc/software/misc/fldigi_beta-1.png

I wonder if Nate, N0NB would enjoy helping?

Thanks Mike
This is great news...your are the first person reporting successful Bayesian decode.
As you play with this version I would appreciate your feedback on things like

  • * Signal strength of successful / non-successful decoding
  • * CW speed - any limits you find when decoder stops decoding
  • * QSB - how does signal fluctuation impact decoding accuracy
  • * Waveforms - using the Scope feature of FLDIGI - any findings on better/worse decoding

Any screenshots  and WAV file captures to document findings would be welcome.

The software is still fragile, will break easily and is not fully integrated with FLDIGI user interface.
You will most likely find the "pmax overflow" bug - symptoms include  CW Rx speed indicator on bottom left corner showing a large negative number, sometimes it goes to a mode where you get only series of letter  E E E E E  etc. You need to restart FLDIGI application as it does not recover from this bug yet.

This is a fairly complex piece of software and it requires still quite a lot of work to make it really useful for the ham community.

Thanks again for all your help and support.

73
Mauri AG1LE


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on December 26, 2013, 06:23:07 AM
Glad to help, but I don't have as much time as I would like to. The Stew Perry contest is this weekend and I have some antennas to work on and new logging software to finish setting up.

I hope you can find others to help you as well. Perhaps if you posted a link to this thread in the Computers and Software forum here and on qrz.com, you will attract others.


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on December 26, 2013, 11:17:15 AM
I hope you can find others to help you as well. Perhaps if you posted a link to this thread in the Computers and Software forum here and on qrz.com, you will attract others.

Great idea  - I did a cross posting in the Computers and Software Forum.

73
Mauri AG1LE


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on December 31, 2013, 09:00:48 PM
Thanks to the alpha testers I have received both feedback and some test audio files to hunt down bugs in this Bayesian Decoder software.

I analyzed in details of the behavior that a few alpha testers have reported.
Here is a  summary of the problem:
http://ag1le.blogspot.com/2013/12/new-morse-decoder-part-3.html (http://ag1le.blogspot.com/2013/12/new-morse-decoder-part-3.html)

In short the speed estimator part of the algorithm that should track and find correct WPM speed on received signals like this:
(http://2.bp.blogspot.com/-Yy-SguKooZY/UsOXS-o9YmI/AAAAAAAAGVM/HExaVssFFI4/s640/coding_OK.png)

is misbehaving when decoder gets too large signals.  The threshold when this happens is very sharp and non-linear - here is error case:
(http://4.bp.blogspot.com/-EhQjwS4I4bQ/UsOXS3Vx3UI/AAAAAAAAGVQ/QcQu-Jci4OM/s640/coding_not_OK.png)

I have converted all the files from C  to C++  to make it easier to re-integrate to FLDIGI.  I will continue cleaning up the code and keep working to improve the speed estimator part.  Once I have the next alpha release ready for another set of tests I will announce it in the fldigi mailing lists and eham.net CW forum.

73 and Happy New Year
Mauri AG1LE


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AD0AE on January 02, 2014, 09:31:09 AM
This is a very basic question, but in what respect is the decoder Bayesian?  What information is being used and 'updated?'

(Forgive me also, I have not fully read this thread)

73s,
Steve
AD0AE


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on January 03, 2014, 02:01:25 PM
I can't test this anymore. I screwed something up when I was playing with the mixer.

Maybe someone can give me some advice. I don't know where to begin to fix this.

I was trying to find the setting in the mixer that would let me adjust the signal level to running applications. In the process, I managed to "kill" the audio the signal to any running applications, including fldigi and qsstv.

The sound from my rig still comes out the computer speakers, as it always has. But that's all.

I restored the old /home/mike/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-mixer.xml but it didn't fix it, even after a reboot. (/home/ is the only backup I have.)

Any suggestions?  I'm using Xubuntu 12.04.3 LTS (Precise), which is Ubuntu with the XFCE 4.8 GUI.


I don't know exactly what Bayesian means, either. I'll concern myself with that after this audio issue is solved. :-)


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on January 03, 2014, 06:52:23 PM
This is a very basic question, but in what respect is the decoder Bayesian?  What information is being used and 'updated?'
Hi Steve
The decoder has several built-in models, such as
  •    * baseband signal channel model
  •    * keystate model
  •    * speed transition model
  •    * Morse symbol transition model
  •    * letter transition model
As the decoder receives samples of filtered audio signal after enveloper detector  (currently at rate of 200 Hz) it updates these models and calculates transition probabilities using Bayesian framework. Sequence of all possible keystate transitions are hypothesized and correlated with the incoming signal , and the most likely sequence is the output as the best estimate.

The complete description is actually much more complicated but essentially this decoder uses Bayesian methods to learn from incoming signals and update models accordingly. More details can be found from here: http://ag1le.blogspot.com/2013/09/new-morse-decoder-part-1.html (http://ag1le.blogspot.com/2013/09/new-morse-decoder-part-1.html)





Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on January 03, 2014, 07:02:02 PM
I can't test this anymore. I screwed something up when I was playing with the mixer.

Maybe someone can give me some advice. I don't know where to begin to fix this.

I was trying to find the setting in the mixer that would let me adjust the signal level to running applications. In the process, I managed to "kill" the audio the signal to any running applications, including fldigi and qsstv.

The sound from my rig still comes out the computer speakers, as it always has. But that's all.

I restored the old /home/mike/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-mixer.xml but it didn't fix it, even after a reboot. (/home/ is the only backup I have.)

Any suggestions?  I'm using Xubuntu 12.04.3 LTS (Precise), which is Ubuntu with the XFCE 4.8 GUI.


I don't know exactly what Bayesian means, either. I'll concern myself with that after this audio issue is solved. :-)

Have you tried using "pavucontrol" ?   I switched from Ubuntu to Linux Mint  15 for my development laptop and pavucontrol seems to work in more reliable manner than other audio mixers. You can install it  with command   "sudo apt-get install pavucontrol".


73
Mauri AG1LE 


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on January 04, 2014, 10:14:58 PM
Have you tried using "pavucontrol" ?   I switched from Ubuntu to Linux Mint  15 for my development laptop and pavucontrol seems to work in more reliable manner than other audio mixers. You can install it  with command   "sudo apt-get install pavucontrol".

Thank you. I installed this, but nothing I do there seems to restore the input to sound recorder, which I had running to test this.

I posted the following to http://ubuntuforums.org/showthread.php?t=2197696&p=12891761#post12891761
Stumped! Sound from speakers, but can't record.

    I was playing with the XFCE Mixer, trying to add/remove controls, and all of a sudden I have no input to Sound Recorder (and other application that require sound input, such as Fldigi and Qsstv). I have no idea what happened, and I am at a loss to fix this.

    I was trying to find the setting in the mixer that would let me adjust the signal level to running applications. In the process, I managed to "kill" the audio the signal to any running applications, including fldigi and qsstv.

    The sound from my rig still comes out the computer speakers, as it always has. But that's all. There's no longer any input to any running application that takes sound input.

    I ran alsamixer and turned everything on.

    I've looked through many threads here and Googled this problem. No luck. I am stuck.

    I restored the old /home/mike/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-mixer.xml but it didn't fix it, even after a reboot. (/home/ is the only backup I have.)

    Any suggestions? I'm using Xubuntu 12.04.3 LTS (Precise), which is Ubuntu with the XFCE 4.8 GUI.

    Any help would be greatly appreciated! Let me know what else I should post



Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on January 25, 2014, 12:17:40 PM
I posted a new release of new Bayesian Morse Decoder on Dave's web site
http://www.w1hkj.com/ag1le/ (http://www.w1hkj.com/ag1le/)

File name is fldigi-3.21.77.bayes.tar.gz 

The "pmax" bug is now fixed in this version.

I converted the software from C  to C++ to enable multiple decoder instances in the future.
I also expanded the automatic speed adaptation range  from 10...60 WPM  to  8...80 WPM,
and included Squelch function to disable the decoder when signal level is below set value.

I tested this version with WAV files recorded from ARRL Straight Key Night - I am getting decent decoding accuracy on hand keyed Morse signals. 

Let me know how this new version works for you.

73
Mauri AG1LE 


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on January 25, 2014, 08:39:33 PM
I posted a new release of new Bayesian Morse Decoder ... Let me know how this new version works for you.

This sounds interesting, and I would love to test it.

I am afraid to install it, though, because the last time I installed your version it overwrote the other version.

I need to figure out how to install more than one version of fldigi independently. Any suggestions?


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on January 26, 2014, 05:35:23 AM

This sounds interesting, and I would love to test it.

I am afraid to install it, though, because the last time I installed your version it overwrote the other version.

I need to figure out how to install more than one version of fldigi independently. Any suggestions?
You can download the tar  file to another directory.
Then  execute the following commands (in Linux shell):   

tar  xvf  fldigi-3.21.77.bayes.tar.gz
cd fldigi-3.21.77.bayes
./configure
make

After compilation you should have executable version in src sub-directory.
You can start  it with command "src/fldigi"  while in fldigi-3.21.77.bayes directory.

If you do the normal  "sudo make install"  it will overwrite your existing version.
This way you can have multiple versions that don't interfere each others.

I had this new version running 3 hours last night while I was listening various CW contest stations.
Seems to be much more stable now...I did not get any "pmax" errors and decoding accuracy was quite good.

73
Mauri AG1LE





Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on January 29, 2014, 04:01:22 AM

This sounds interesting, and I would love to test it.

I am afraid to install it, though, because the last time I installed your version it overwrote the other version.

I need to figure out how to install more than one version of fldigi independently. Any suggestions?

Hi Mike

Any luck installing this new version?  Have you had time to give it a try yet?

73
Mauri AG1LE


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: G0UKB on February 24, 2014, 04:32:34 AM
Hi Mauri - just to let you know I've built your version (on Mint 16) and have successfully decoded. On first impressions it certainly seems better than the previous built-in decoder for FLDIGI. in a couple of weeks there is the UK Commonwealth contest (BERU) which is CW and restricted to UK and our commonwealth countries so it is a fairly relaxed contest with no huge pile-ups since Europe and the USA can't enter. I hope to enter this year with CW treated purely as any other data mode on FLDIGI using your decoder. Last year I cobbled together a solution using WD6CBF's CW Decoder on Windows with a logging program since WD6CNF's decoder seemed the best in tests.

Having a decent decoding engine inside FLDIGI will, of course, make this so much easier this year. Should be interesting.

Thanks for the huge amount of work that must have gone into this project and should you find any bugs or improvements then I'd love be on the test list.

Brian G0UKB


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: N3HEE on February 24, 2014, 04:10:48 PM
Errors trying to compile and test.  Followed your instructions above and get the following output from make....  Please help !  Thanks -Joe n3hee

 make
Making all in po
make[1]: Entering directory `/home/joe/fldigibayes/fldigi-3.21.77/po'
make[1]: Leaving directory `/home/joe/fldigibayes/fldigi-3.21.77/po'
Making all in doc
make[1]: Entering directory `/home/joe/fldigibayes/fldigi-3.21.77/doc'
make[1]: Nothing to be done for `all'.
make[1]: Leaving directory `/home/joe/fldigibayes/fldigi-3.21.77/doc'
Making all in src
make[1]: Entering directory `/home/joe/fldigibayes/fldigi-3.21.77/src'
make  all-recursive
make[2]: Entering directory `/home/joe/fldigibayes/fldigi-3.21.77/src'
make[3]: Entering directory `/home/joe/fldigibayes/fldigi-3.21.77/src'
  CXX    fldigi-xmlrpc.o
In file included from ./include/Fl_Text_Editor_mod.H:37:0,
                 from ./include/FTextView.h:34,
                 from ./include/FTextRXTX.h:28,
                 from ./include/fl_digi.h:34,
                 from misc/xmlrpc.cxx:58:
./include/Fl_Text_Display_mod.H:111:5: error: ‘Fl_Fontsize’ does not name a type
./include/Fl_Text_Display_mod.H:262:3: error: ‘Fl_Fontsize’ does not name a type
./include/Fl_Text_Display_mod.H:268:17: error: ‘Fl_Fontsize’ has not been declared
./include/Fl_Text_Display_mod.H:477:3: error: ‘Fl_Fontsize’ does not name a type
./include/Fl_Text_Display_mod.H: In member function ‘void Fl_Text_Display_mod::textsize(int)’:
./include/Fl_Text_Display_mod.H:268:33: error: ‘textsize_’ was not declared in this scope
make[3]: *** [fldigi-xmlrpc.o] Error 1
make[3]: Leaving directory `/home/joe/fldigibayes/fldigi-3.21.77/src'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/home/joe/fldigibayes/fldigi-3.21.77/src'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/home/joe/fldigibayes/fldigi-3.21.77/src'
make: *** [all-recursive] Error 1
joe@ubuntu:~/fldigibayes/fldigi-3.21.77$


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on February 24, 2014, 06:41:31 PM
I googled the error and found references to fltk v1.3.0 version. Looks like Dave W1HKJ did some changes about 1.5 years ago to enable compatibility to this later version. Can you update your fltk version to v1.3.0 and try building again?

73
Mauri


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on February 24, 2014, 07:16:33 PM
Hi Mauri - just to let you know I've built your version (on Mint 16) and have successfully decoded. On first impressions it certainly seems better than the previous built-in decoder for FLDIGI. in a couple of weeks there is the UK Commonwealth contest (BERU) which is CW and restricted to UK and our commonwealth countries so it is a fairly relaxed contest with no huge pile-ups since Europe and the USA can't enter. I hope to enter this year with CW treated purely as any other data mode on FLDIGI using your decoder. Last year I cobbled together a solution using WD6CBF's CW Decoder on Windows with a logging program since WD6CNF's decoder seemed the best in tests.

Having a decent decoding engine inside FLDIGI will, of course, make this so much easier this year. Should be interesting.

Thanks for the huge amount of work that must have gone into this project and should you find any bugs or improvements then I'd love be on the test list.

Brian G0UKB


Thanks Brian

I will keep you posted once I get the next set of bug fixes and improvements done. Speed estimation algorithm needs some work, as the decoder often misses first character after a long pause.

I have an experimental standalone version where I have also tested expanding trellis path length from current 25 up to 100.  This requires much more CPU capacity, even my Intel I7 at 3.4 GHz takes significantly longer to decode. Results especially in noisy signals exceeded my expectations.  This Bayesian algorithm is the most promising so far, and I have tested quite a few different approaches already.

Good luck with the contest and please share your experiences with this decoder, both good and bad.

73
Mauri AG1LE


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: N3HEE on February 25, 2014, 01:41:24 AM
Mauri, I updated to fltk1.3 and was able to build.  However now getting audio error.  E: trx_trx_receive_loop: Sound error: No such file or directory  I see that OSS is the only choice for soundcard.  My system uses portaudio.  -Joe


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: N3HEE on February 25, 2014, 04:33:27 AM
Ok, got portaudio support to compile with portaudio19 dev library installed.  Decodes ARRL code practice file flawlessly.  I will do some on air testing tonight and report back then.  -Joe


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: N3HEE on February 25, 2014, 09:44:34 AM
Mauri, I did some testing today.  I have to say the legacy decoder did a better job.  Are there any settings I have to adjust for optimum bayes decoding? I was just checking the bayesian filter box on the configuration page. I kept all the other settings and levels the same during the test.  I will continue to test more later.  -Joe


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: AG1LE on February 25, 2014, 08:07:16 PM
Mauri, I did some testing today.  I have to say the legacy decoder did a better job.  Are there any settings I have to adjust for optimum bayes decoding? I was just checking the bayesian filter box on the configuration page. I kept all the other settings and levels the same during the test.  I will continue to test more later.  -Joe
Hi Joe

Try to keep the signal volume level relatively low.  The waterfall background should be blue. If the volume is so high that background turns yellow the decoder will have problems. Otherwise the default settings  (matched filter checked) should work fine.

73
Mauri AG1LE


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: N3HEE on February 26, 2014, 09:31:39 AM
Mauri, My levels were pretty low as you described.  Sorry but the legacy decoder worked better in all cases.  Honestly though,  the legacy decoder doesn't work all that well either compared to others I have used.  How much of the legacy decoder code are you using?  I will keep an eye on your development.  I think it's pretty interesting work.  Thanks -Joe


Title: RE: New Bayesian Morse decoder available for alpha testing
Post by: W0BTU on February 27, 2014, 09:12:29 PM
Try to keep the signal volume level relatively low. 

I have just been way to busy to try the latest changes, but my observations confirmed that. Turn down the volume. :-)