PDW Anyone else getting crashes?

[rabrol]

I had PDW running perfectly stable for years, but recently it has started crashing after random periods of time (sometimes 10 minutes, sometimes an hour).
Reports a BEX error every time. I'm running Windows 7 with an older version of SDR#, but also tried with the new SDR++ and the same is happening, so not the feeder software.

I tried a separate install on another Win 7 laptop, and the crash is happening on it as well. I don't know why.

Tried the fixes suggested online (click the Data Execution Prevention tab, and then click Turn on DEP for all programs and services except those I select - at which point I added PDW). This has not helped.

Also tried running it in XP compatibility mode, but still suffering the crashes.
Anyone else had PDW crashing on them lately?

 

[AM909]

I had PDW running perfectly stable for years, but recently it has started crashing after random periods of time (sometimes 10 minutes, sometimes an hour). ...

My initial gut reaction was that it's something unusual in the signal(s) you're monitoring that wasn't there before, maybe caused by a software update to the paging terminal(s) you're listening to. Can you isolate it to one particular signal and record and reproduce it (using the baseband recorder and source file playback tools in SDR#)?

 

[rabrol]

Interesting thought.
I only monitor 1 frequency on which all traffic is POCSAG 512, but I hadn't considered the signal itself as having changed. I can maybe give this a go.

 

[ka3aaa]

PDW is very sensitive and can be very difficult to set up at times and uses very little audio for its input. Play with it and you will get it after a while., make minor adjustments at a time and watch and see what happens with it.

 

[rabrol]

I think the audio levels are pretty good. It shows a perfect 100% decode rate. Then randomly crashes. But I can adjust the volume lower to see if that makes a difference.

 

[Spleen]

Which version of PDW? And does it give any other error description or log when it throws the BEX error?

 

[rabrol]

I'm running version 3.12 on one old laptop, and 3.2b01 on the other.
Both are crashing with the BEX error - both running Windows 7.

The 3.12 is on the computer that had been running well for months at a time.
Both are using different SDRs (generic R820t) with the appropriate ppm.

I have also tried changing the source software. The crashes happen with SDR# and SDR++. Haven't tried a 3rd option.
Lastly, I changed the bandwidth and volume settings multiple times, but it only results in decreasing the decode rate which is always at 100%.

I'll update with more details of the crash when it next happens.

 

[rabrol]

OK, in less than 10 minutes it crashed. This is the 3.12 version.
Windows dialog box appears saying "POCASG, FLEX, ACARS, MOBITEX & ERMES Decoder has stopped working. Check online for a solution and close the program, or Close the program.

When i hit the Problem Details I receive the following info :
Problem Event Name : BEX
Application Name : PDW.exe
Application Version : 3.1.0.0
Application Timestamp 51e71f16
Fault Module Name : StackHash_e98d
Fault Module Version : 0.0.0.0

Further down it reports
Exception Offest : 20202020
Exception Code : c0000005
Exception Data : 000000008

Additional Information 1 : e98d
Additional Information 2 : e98d...... (a large hex value)
Additional Information 3 : 6eab
Additional Information 3 : 6eab..... (another large hex value)

 

[AM909]

I'd suggest using SDR#'s "Recording" plugin to record the audio. Once you have a crash, see if you can duplicate it by playing back the audio into PDW. If that fails to reproduce the crash, try recording in baseband mode and playing it back through SDR# to see if you can reproduce it.

 

[rabrol]

I have made some modifications to the filter list.
After I made the filter list change, it did crash after an unknown period of time, but has now been running for a couple of hours without crashing.

The problem with recording is that I'll have to be in the room the entire time, keeping an eye on it. The crashes appear random - sometimes after a few moments, sometimes after hours. I can try recording one that happens in a short space of time, but it may take a while to capture.

 

[Spleen]

When you installed it on the other laptop, did you copy over the same filter file(s)? I wonder if there's a corrupt entry or a corruption in the filter file. Maybe nuke your filter file and pretend you're starting from scratch, see if still crashes.

I have made some modifications to the filter list.
After I made the filter list change, it did crash after an unknown period of time, but has now been running for a couple of hours without crashing.

The problem with recording is that I'll have to be in the room the entire time, keeping an eye on it. The crashes appear random - sometimes after a few moments, sometimes after hours. I can try recording one that happens in a short space of time, but it may take a while to capture.

 

[kruser]

I wonder if PDW does not like the encryption message structure that's been introduced into paging systems and crashes when it sees an encrypted message.
You would think it would just treat those messages as garbage but maybe not.

I may have to dig the stuff out and test it as it's been quite a while.
I use discriminator tapped radios though along with 4-level slicers as we had a few 6400 baud 4 channel Flex systems here back in the days.
I think today there may be just one VHF system left that was always Pocsag and maybe 4 or 5 Flex or Pocsag systems in the 929 to 931 range but that's it.
When I tune through the old paging bands here, they are quiet of paging signals but full of P25 voice and control channels now in the VHF ranges.
Only one VHF flamethrower left here.

 

[morfis]

Errors in the filters file usually result in the program not running at all. Never known one cause a crash.
Here there are encrypted messages but these display as gibberish - again, I have never seen a crash occur as a result.

As things had run fine for years but suddenly you get crashes the most likley cause would seem to be whatever changed on the PC...virus, security update, driver change or whatever (and perhaps not even specifically related to PDW). I have had that happen when a USB driver had been updated....and there is nothing in the multiple instances of PDW I run which is using USB!

 

[rabrol]

Thanks for the suggestions & thoughts everyone. I think the problem has been solved, and you'll be surprised by the reason!

I disabled "Block duplicate messages" in settings. Since doing so, no crash. PDW has been happily decoding for over 16 hours now. I had previously selected to block duplicates if the text was the same as previous message. Of course I'm seeing all the duplicates now, which is a little annoying, but I would rather see duplicates than not be able to scroll back through messages!

With regard to the other comments, when I had set up PDW on a second PC (since the 1st kept crashing), I re-entered the filters, and simplified them. I brought it down from 4 filters to 1, just in case that was causing the problem.

The vast majority of messages on this system are in the clear. There are a few ENC ones - maybe a couple of day I would say. As others have reported, gibberish is all that shows up on screen.

In terms of changes on the PC - I had wondered about this, but with Win 7 not being supported anymore was hoping this wasn't a cause. Could possibly have been anitvirus, but I know MS did roll out a Win 7 update a while ago too.

Anyway thanks all for the suggestions. I'll report back if it crashes again, but for now, fingers crossed!