Skipping around in playback using PowerSDR

[steve_qix]

Hi !

I have a 4 gig recording of a section of 160 meters that I made with PowerSDR.  I can "play" this back through the receiver software, and adjust the RX bandwidth, mode, etc. etc., but there does not seem to be a way of skipping around in the recorded data.

Does anyone know of a way to do this?  If there is a way to do it, it's certainly not obvious!

Thanks and Regards, Steve

[n3lrx]

What format does it save the recording as? If it's a standard audio editing application  should do the trick. It's been a long time since I've used Wiondows, But if you're running Linux I may suggest Audcity, it does allow you to snoop around in the file with ff and rewind as well.

[steve_qix]

Yeah, if this were a standard .wav file, there would be no problem.  Yes, it is a .wav, but it's the entire spectrum that the A to D sees, saved to a file.  You then "play" this via PowerSDR, which then demodulates the signal(s), etc.

I would think the development team for PowerSDR would have provided such a mechanism, since it is (or seems to me) to be a basic requirement for playing back any sort of transcript through the software that created it.

The AMM-SD1 modulation monitor has a similar feature, and you can jump around anyplace in the transcript file and start from there.  Sure makes it easy when you've got hours recorded !!!

This particular PowerSDR capture spans hours of time.

We are having a problem on 1945 kHz (which is the frequency of the Grey Hair Net, a VERY old AM net) with some bucketeers in the Southern portion of the US who come on EVERY NIGHT and take over the frequency from whatever QSO happens to be there.

Last night I started recording at about 9:30PM, and sure enough they showed up a bit later, right on schedule.  Furthermore, earlier they were up frequency about 5kHz conspiring (on the air) to come down to 1945 and knock us off the frequency.

I politely told them the frequency was in use, etc. etc. etc...... everyone here knows the drill.  Suffice to say, they hung themselves with their own words when they stated their reasons for not leaving the frequency, that they have a right to the frequency and that we should move.

There also was talk from them about my property, after they looked it up on QRZ and Google maps; about some of them "taking a long ride", and a considerable discussion about the guns they have..... all recorded.

Anyway, that's why I want to be able to skip around and capture the relevant sections.

[n3lrx]

So much for 160 being the gentleman's band. Seems the recent watering down of the license requirements has backfired, letting the CB mentality run free on ham bands. Threats like that are certainly what I would expect from a CBer not a ham.

The only difference is a lot of us have our home addresses waving in the wind for anyone to look up. Not as easy for a CBer to find another CBer. I'm sure these trolls don't have the skill to actually triangulate a signal so they choose the ham bands as a target because we are required to essentially give out our home address every 10 minutes. I'll be looking into a PO Box in the near future.

[n3lrx]

Steve, One thing you could try that I didn't think about is play it in the SDR application and record it onto VHS. You can get a few hours of audio on a decent sized VHS tape. Just set it and walk away for a while. Then you can fast forward, rewind, whatever you have to do to get the desired segments of audio. Then record the bits onto your hard drive and then burn it to CD to submit as evidence if it goes that far. Which if they are making personal threats it has already gone that far.

But you're right the SDR software should have it's own capability to do so.

This idea is a bit out there, and requires a bit of work, but it's effective.

[w1vtp]

Steve

You can manipulate the wav file by using something else other than PowerSDR.  I'm using Windows 7 so it might be a bit different in other OS's

Drill down thusly:  

\USERS\"your username"\APPDATA\FlexRadio Systems\PowerSDR v "#.#.# (your version of PowerSDR)\SDRQuickAudio.WAV

You have to copy that file off that directory right away because every time you do a recording it gets overwritten.  From there the file can be renamed and I recommend converting it over to mp3.  That file can be managed by your favorite WAV /mp3 file utility.  Unfortunately, if you have made any recordings since then, it gets overwritten.

PS:  I've added a snapshot

[w1vtp]

Now, to comment on the problem.  I wasn't listening to what went on but (if I can editoralize) we seem to have a problem in amateur radio of what I call "angry old men" who delight in denigrating and causing trouble with folks who schedule so called nets which are not much more than an extended QSO that is directed by a host.  These individuals (who appears to me) do not have a life and take delight in neighborhood bullying.  It's sad.  I like to think of the hobby of amateur radio as grown up folks who delight in the art of conversation over the air.

If I can guess - it may be that some time in the past the net may have opened up on frequency, or close by, that someone was already using and thus was born a grudge - that's just a guess.  My suggestion is that if it is known that there is already a QSO in progress that a "net" have a policy where it QSY's up or down to the nearest open frequency more than 5 KC's away and run the net from there.

I'm net mgr of the Vermont Net, a ragchew net on SSB and our policy is to not insist that we have the frequency that the net meets on If there is a QSO already in progress. If we cannot move up or down to a frequency that is clear from that QSO then  the net is cancelled for that session.  It's really not a big deal for us as we know what the policy is.  I cannot remember the last time we had to resort to cancelling a session.  The QSY method works for us.  Meanwhile, I assume diplomacy with the other folks is not an option.  Sad. I understand what is going on - that these folks come on frequency and cause interference as per part 97 of FCC rules and regs...

This is just my opinion: please don't chew me out.

Al

[steve_qix]

Hi Al,

Ok on the interference problem - Oh, this has *nothing* to do with the Grey Hair Net - nothing, other than we are using the same frequency.  Just wanted to make that clear 

On the SDR recording, I am not using SDRQuickaudio nor am I making a recording of demodulated audio in any way.  This is a different recording that PowerSDR will let you make.  It is a capture of the A to D converter.  Warning:  it ABSOLUTELY CONSUMES disc space at an *amazing* rate, because it is capturing the sample rate you are using over the SDR hardware's bandwidth !!  I created a 4 GIGabyte file last night in not too long a period of time.  Wow is all I can say.

[n3lrx]

Well, it seems to me that people of that mentality mentioned in this thread will go to any frequency the net chooses to operate on just to disrupt the net. So if the net is QSY'd they'd probably go there too. On the internet these people are called 'trolls' they are what you'd call a 'lid' on ham radio. They don't follow any etiquette already put in place their premeditated intent is to disrupt.

Anyone that is going to result to personal threats by referencing a particular operators home and bringing guns into the equation is more than just an angry old man problem and the operators who join the net have a right to be concerned.

But you're right, no one including a net owns a particular frequency and moving the net when the frequency is in use should be a gentleman's first choice. But when you've got people 5 kcs away plotting to disrupt the net before it even happens. That's premeditated. Totally different ballgame.

On the other hand if a gentleman(men) know(s) a net is on frequency at X time, they should be the ones QSY'ing to another frequency, or join the net. It's easier to move a couple of people rag chewing to another frequency than it is to move an entire net and any gentleman should understand that.

I personally don't have a problem QSY'ing to make room for a net, or joining the net while it's in progress and resume my rag chew afterwards.

[DMOD]

I'm net mgr of the Vermont Net, a ragchew net on SSB and our policy is to not insist that we have the frequency that the net meets on If there is a QSO already in progress. If we cannot move up or down to a frequency that is clear from that QSO then  the net is cancelled for that session.  It's really not a big deal for us as we know what the policy is.  I cannot remember the last time we had to resort to cancelling a session.  The QSY method works for us.  Meanwhile, I assume diplomacy with the other folks is not an option.

Now this is the way to conduct a net.   My hats off to you Al.

Unfortunately, it seems too many nets and net controllers are not as flexible and seem to think they own the frequency.

We are having a problem on 1945 kHz (which is the frequency of the Grey Hair Net, a VERY old AM net) with some bucketeers in the Southern portion of the US who come on EVERY NIGHT and take over the frequency from whatever QSO happens to be there.

Last night I started recording at about 9:30PM, and sure enough they showed up a bit later, right on schedule.  Furthermore, earlier they were up frequency about 5kHz conspiring (on the air) to come down to 1945 and knock us off the frequency.

I politely told them the frequency was in use, etc. etc. etc...... everyone here knows the drill.  Suffice to say, they hung themselves with their own words when they stated their reasons for not leaving the frequency, that they have a right to the frequency and that we should move.

There also was talk from them about my property, after they looked it up on QRZ and Google maps; about some of them "taking a long ride", and a considerable discussion about the guns they have..... all recorded.

Anyway, that's why I want to be able to skip around and capture the relevant sections.

Once you get the relevant section(s) separated, I would definately send this to the FCC.

Phil - AC0OB  

[WB2EMS]

On the SDR recording, I am not using SDRQuickaudio nor am I making a recording of demodulated audio in any way.  This is a different recording that PowerSDR will let you make.  It is a capture of the A to D converter. 

Steve,

I think I would approach this by loading the file up in PowerSDR and letting it play and capturing the audio output from that (via VAC probably) into an mp3 or wav recorder on the same machine - I would use the Windows version of Audacity which I've found very handy and reasonably easy to learn. Let that run overnight or for however long the recording was. Then you can use Audacity to slide around in the mp3/wav file to find the pertinent audio, then mark it and export it to another file, eventually ending up with an MP3 of the 'highlights'.

You'll have to 'tune' around in the PowerSDR file while it's playing probably to get the relevant bits on the various frequencies to be rendered to audio. You can do that at various points, capturing each into a separate file, then use Audacity to link those files into the 'highlight' file output.

Hope that helps.

Kevin, WB2EMS

[n3lrx]

That's cool I didn't know there was a Windows version of Audacity. (Shows how long it's been that I've visited their site.) It's a wonderful multi-track recording program with lots of potential 'power' in recording. I use it on my Linux installation quite regularly. It's quite easy to master. I was used to Cool Edit Pro and the two are very similar.

[n3lrx]

OK, I just tried to record a radio stream playing using Audacity and it doesn't record anything. I don't know if the Windows version of it will or not. PulseAudio on Linux is a bit more pickier than Windows sound management is so it may work on Windows.

[W1AEX]

Steve,

With I/Q recordings (wav files in a "pre-processed" format that are not at all related to the familiar audio wav format) there is no way to move to different places within the spectrum recording using the PowerSDR player. You are stuck with running it right from the beginning until you get to where you want within the recording. This is a feature that has been requested numerous times but Flex doesn't seem interested in doing anything with it. If I want to make a video of an I/Q recording that I made in PowerSDR I use video/audio capture software (Camtasia or CamStudio Freeware) to directly re-record the segment of any I/Q recordings that I am interested in as PowerSDR plays it back within its own player. The capture software makes an HD video file in MP4 format and if you use a resolution of 1280x720 it will be displayed in 720p HD format if you upload the file to YouTube. It sounds more complicated than it actually is. The picture below shows Camtasia set up with a direct audio connection to PowerSDR through VAC and the PowerSDR display bracketed to capture only PowerSDR. Depending on what I am planning to do, sometimes I set it up so only the Panadapter is captured in the video.

The stuff above might not be helpful as far as working with the 4 GB file you are dealing with, but the following information might help. When I make extended audio recordings I use Adobe Audition (or Audacity) and use VAC to route the audio stream from PowerSDR directly into the recording software. This way it will record directly to mp3 format and it creates a file that is way more manageable in size than the "post processed" audio wav files created by PowerSDR. To make an editable file from your 4 GB I/Q recording, you could take the I/Q file that you made and as it is playing back in PowerSDR, you can port the audio stream out to Audacity or Audition through VAC and then edit the resulting mp3 file if you wish.

The record function within the PowerSDR interface is not well documented and lots of times people are confused about the difference between the two options of "Pre-Processed" and "Post Processed" recordings. The "Pre-Processed" setting records the entire spectrum bandpass (up to 192kHz) in a proprietary wav format compatible only with the PSDR player and the "Post Processed" setting records only the audio stream in the standard audio wav format most are more familiar with.

It would have been nice if all this functionality was within PowerSDR but since the vast majority of people would probably never use it, I suppose it makes sense to leave it to third-party software.

Rob W1AEX

(Note: Hah! Serves me right for starting this post and messing around with a bunch of other stuff before finishing it and posting it. Kevin WB2EMS already has the solution clearly stated above. Yeah I know, I just clicked through the "Someone has posted to this thread blah blah" warning...)

[n3lrx]

Yeah, Audition, that's what used to be Cool Edit. Adobe bought Syntrilliam Software and changed the name. It's a real shame I miss Cool Edit. I used Cool Edit for production at a few radio stations I worked at. Very powerful software. Great economical replacement for SAW or ProTools. The plugins and scripts were all open source and there were a ton of them.

Apparently Cool Edit Pro 2.1 is a free download now. I didn't try it on Wine. But most likely it doesn't have the Farfignewton (or whoever) mp3 plugin. The only one that wasn't free because of the copyrights and royalties involved.

[N2DTS]

I think there are sdr programs where you can skip around in the time window, but Psdr is not one of them.

I do not record, so I never tried it, but my sdr-iq runs with 3 programs, and at least one allows you ro skip around in time.

It seems to me, that much of night time ham operation involves hate and fighting like children.
This seems to be what many enjoy, including people on AM.
Instead of ignoring something, they go on and on about it, for a long time, most nights, when its so easy to just select the other sideband and not even hear whatever.

[K5IIA]

I use pmsdr with hdsdr software. And if I record the rf and not just the af. I can play it back and go anywhere in the 96k or so of bandwidth I want and listen in anymode at any width I want to. If that is what you are talking about.

[Opcom]

There also was talk from them about my property, after they looked it up on QRZ and Google maps; about some of them "taking a long ride", and a considerable discussion about the guns they have..... all recorded.

terroristic threats across state lines. felonies. press it w/ the law. get 'em cuffed and stuffed and they'll cry like little children.
Why am I not afraid of other people's mouthing about guns; those are just 'things'. It takes a tough mean man to go thorough wit what they said and you probably aint dealing with that just a bunch o noisy pieholes.

[N2DTS]

We are talking about moving around in TIME.
If you record 1 hour of spectrum, say from 10 to 11 pm, and want to listen to something at 10:45, you have to start from 10pm and spend 45 minutes waiting for 10:45 on some programs.

I use pmsdr with hdsdr software. And if I record the rf and not just the af. I can play it back and go anywhere in the 96k or so of bandwidth I want and listen in anymode at any width I want to. If that is what you are talking about.

[K5IIA]

We are talking about moving around in TIME.
If you record 1 hour of spectrum, say from 10 to 11 pm, and want to listen to something at 10:45, you have to start from 10pm and spend 45 minutes waiting for 10:45 on some programs.

I use pmsdr with hdsdr software. And if I record the rf and not just the af. I can play it back and go anywhere in the 96k or so of bandwidth I want and listen in anymode at any width I want to. If that is what you are talking about.

ok I didn't understand. my only experience with sdr rx'ers is my setup. and you can jump around all you want. in time or freq. when we have problems of qrm I always hit the record button and go back and listen to what was going on around us and try to see where the problem came from.

[steve_qix]

We are talking about moving around in TIME.
If you record 1 hour of spectrum, say from 10 to 11 pm, and want to listen to something at 10:45, you have to start from 10pm and spend 45 minutes waiting for 10:45 on some programs.

I use pmsdr with hdsdr software. And if I record the rf and not just the af. I can play it back and go anywhere in the 96k or so of bandwidth I want and listen in anymode at any width I want to. If that is what you are talking about.

ok I didn't understand. my only experience with sdr rx'ers is my setup. and you can jump around all you want. in time or freq. when we have problems of qrm I always hit the record button and go back and listen to what was going on around us and try to see where the problem came from.

What are you using?

[K5IIA]

Pmsdr hardware. With hdsdr software.

[steve_qix]

Pmsdr hardware. With hdsdr software.

Thanks!  I wish PowerSDR had this feature.

[KD6VXI]

Reaper is a wonderful audio processing application.

I use it for audio processing instead of rack mount equipment.   Izotope plug-ins make beautiful audio.

--Shane
KD6VXI