Natural VLF Radio

[Aaron]

Stephen McGreevy will be presenting On the Art of Natural VLF Radio Field Recording.

Stephen McGreevy Presenting On the Art of Natural VLF Radio Field Recording - 2015 Energy Science & Technology Conference

[spacecase0]

I love the VLF Radio,
had no idea that it changed before an earthquake,
will have to start listening daily again

[Aaron]

datalogging earth sounds

Would be cool to datalog the output of the headset jack. My receiver is one that I purchased from Stephen McGreevy last year.

I have Cool Edit Pro - but that would take up way too much space.... has to be something simpler that can be exported to Excel to see a graph.

[dR-Green]

Would be cool to datalog the output of the headset jack. My receiver is one that I purchased from Stephen McGreevy last year.

I have Cool Edit Pro - but that would take up way too much space.... has to be something simpler that can be exported to Excel to see a graph.

I dare say that it would theoretically take about the same amount of space. A data logger would take a sample and log the voltage at a certain time interval, usually as text or something which is convenient for importing to Excel. A sound card does exactly the same thing, but the audio program stores the sample voltage as an audio file. I'm not sure what role bit depth plays in this case, but a 8kHz mono audio recording would be like a data logger sampling voltage 8000 times per second. So you would think that the amount of data or file size would be the same if the sample rate is the same.

This can convert data to wave, but what you need is wave to data, unless you just view it in the audio editor, or get some sound card scope software that can log the data as text.

Sound File Write VI - LabVIEW 2012 Help - National Instruments

On a related note, I use a PicoScope which also has data logging function, but the minimum time interval is 30 or 60 seconds so it would be useless in this case. You probably don't need 8000 samples per second but you should be able to input a custom sample rate in Cool Edit Pro to get the file size down and still record a good amount of data.

[Aaron]

WR3 Receiver

e useless in this case. You probably don't need 8000 samples per second but you should be able to input a custom sample rate in Cool Edit Pro to get the file size down and still record a good amount of data.

That all makes sense - Cool Edit can do as low as 6000 sample rate, mono at 8 bit resolution. I think I was recalling recording some conference calls way back on it with a much higher sample rate and the chip water cooler fan was wailing like a banshee. Never used the real low sample rate before but maybe perfect for something like this.

I know Eric likes the analog chart recorders, but something like this I'm sure could do the job of recording the signals. I'd imagine that over time, ever a 1 sample per second would show a picture of what is going on.

Maybe it wouldn't take up that much space or memory. Just looking at the audio wave form is all I'd be looking for anyway and that would be simpler than doing any conversion. We don't have earthquakes in this area - at least very rarely, but would be interesting to see if something builds up before a rainstorm, lightning storm, etc...

This is the exact receiver I purchased from Stephen McGreevy: 2014-2015 WR-3 Model VLF Whistler-Receiver Order-Form Page (Rev. December 2014)

This thing is so sensitive that if you have headphones on with the antenna out all the way - someone can be about 20 yards away and if they walk down some concrete steps and take their fingernail and scratch the top of the metal hand rail just barely, you can hear it in the headphones as if they're scratching the plastic case on the headphones themselves. Really trippy.

[spacecase0]

could you do an FFT on the data and do a peak hold for a second or so and only save data for each frequency, maybe 64 band pass sections or so of them,
should be way less data to store
I know it is possible, but I hate writing software

[BroMikey]

could you do an FFT on the data and do a peak hold for a second or so and only save data for each frequency, maybe 64 band pass sections or so of them,
should be way less data to store
I know it is possible, but I hate writing software

Hi spacecase0

I know you are talking to Aaron about these complicated ways of storing data that I don't really know much about, but let me tell you what I did in the 90's. I had a radio program and it used a lot of memory.

I tried all kinds of soft wares an compression formats to store audio or audio and video A/V.

One of the best things I have is a capture card. maybe this is to elemental and you already know this? Some of them are called "All in Wonder" capture cards.

What that card would do for me was amazing. It had built in memory and it could be set to save the file "All compressed" to the small xvid format WHILE it was capturing.

What was a 1gb file was now only a few mgbs. I had some files down to 6mbs for A/V and they looked good. I did work with the "REAL PRODUCER" one time too. It is free from the REAL PLAYER folks. All free.

As long as I had the right capture card installed on my PC (Hardware card) I could do miracles all in one shot. I hooked the camera to the capture card on the back of the PC.

If you look on ebay you can find capture cards with software. Some are not cheap as they have more horse power to compress and store files without lose of data.

I found DivX, Xvid and 264 my favorites. Once you get the settings right you just name the file and pull the trigger. My files were 1 hour or 2 hours long, maybe you can't use that method.

I just had to share that even if you already knew. Then I got a new PC and it does not have a capture card so i really miss the card. The old card was under win98. Way back in the day. I had win95 for a while too.

Mikey

[spacecase0]

sounds like a fantastic capture card that solves all the issues,

I would likely end up building my idea in almost all analog hardware,
then capture the end result in a very slow sampling rate A to D card so it would not take much memory at all
but I have quite a few projects that I want to do first, can't get to scattered or I get nothing done

[brian516]

Would be cool to datalog the output of the headset jack. My receiver is one that I purchased from Stephen McGreevy last year.

I have Cool Edit Pro - but that would take up way too much space.... has to be something simpler that can be exported to Excel to see a graph.

Aaron,

Maybe Visual Analyzer would be of use in this situation. I haven't really played with it all that much yet, but it has loads of features including graphing, and it seems to me like this would be perfect for what you want. Plus it's free for private use. You could purchase a license for it if you wanted to use it for anything other than personal use, which I think is only about $30.00.

Visual Analyser

Instead of it's input being some sort of scope probe, it is set up to take it's input from a microphone or you can run a loopback internally on your PC so it takes it's measurements from the audio that is being played thru your PC speakers while you are listening to it. I haven't tried to save any files off of it and export them to another program, but I'm sure it can be done.

Brian

[Why-me]

2016 WR-3 Model ELF/VLF "Natural Radio" Receiver

I just ordered mine. I must wait 4 to 6 weeks for delivery.

[Sputins]

VLF detector build

I also thought McGreevy's VLF circuits were cool and fun so I built myself one.

I built it about a month ago and it works very well. As far as natural signals, I've only managed to pick up lightning crackles from my local area thus far. Perhaps once I'm away from interference and obtain a better whip antenna, I might do a bit better.

Nevertheless it is a good unit and project to build. It also serves very well for picking up stray VLF signals in and around the house and the workplace. Its amazing what you discover...



I built the BAS40 / WR-3 version from recycled parts and electronics I already had on hand except for a few pots and a BNC connector so I didn't have to spend much money on it.



I had it switched on and it easily detected the flash from the camera used to take the photo.

So I would recommend either buying one of McGreevy's well refined and finished units or constructing your own unit. - Well worth the effort.

[Ernst]

Sputin,
Nice work
I'm not saying that I will immediately build one, but it is interesting and maybe someone else would like to follow your suggestion to build one...
So could you provide the diagram?

Ernst.

[Sputins]

Schematic.

Sputin,
Nice work
I'm not saying that I will immediately build one, but it is interesting and maybe someone else would like to follow your suggestion to build one...
So could you provide the diagram?

Ernst.

Thanks Ernst.

I didn’t upload a schematic picture to my imageshack but the schematics for the bare bones unit, the BAS40 and WR3 can be found on Stephen McGreevy’s site. You’ll get the general idea.. It’s a JFET input circuit driving a simple audio amp. There is also a magnetic loop variant schematic which might be of some use for Tesla coil builders…

Stephen’s site: auroralchorus.com - Natural VLF Radio - Sounds of Space Weather - The Music of the Magnetosphere
The top schematic is what I worked with: http://www.auroralchorus.com/wr_3_mod_schematics.jpg

[Why-me]

Other uses for the WR-3

Hello fellow citizens, I have found that the unit will help you with your electronics building in the area of transmitted signals from your running circuits.

If you wish to quiet down your build, the WR-3 will pick up the noises caused by transistors and other switching devices.

I demonstrate this on my 4 foot Bedini build using an oscilloscope probe with cover, to pick up the different audio pitches from one 8 circuit build to another.

The car tags are machined with holes to mount on the heat sinks to capture the forced air generated by the wheel, then covered with infowars bumper stickers to hide my location.

[Why-me]

Perhaps I might try this.