VLF Dawn Chorus Capture, Oct 3, 2025

[Gedas V]

Hello group. I wanted to share my first dawn chorus capture. By dumb luck I was up at 4 AM watching a very corny sci-fi movie while monitoring VLF. Out of the blue starts the sound of hundreds of chirping birds. The event lasted about 20 minutes and not anything I will soon forget. 73 Gedas W8BYA EN70JT (NE Indiana).  Below is a portion of the capture which I put on YouTube.

https://www.youtube.com/watch?v=u_N83W_4vWQ&t=32s

[J. Gordon Beattie, Jr.]

Gedas,

What frequency, mode,  bandwidth and antenna did you use to receive this signal?  It was really cool to hear.

Thanks for capturing and sharing your sound.

73,

J. Gordon "Gordie" Beattie, Jr., W2TTT 

201.314.6964 

W2...@ATT.NET 

Gordon.B...@VIAVISolutions.com 

Get On The Air! 

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From: ham...@googlegroups.com <ham...@googlegroups.com> on behalf of Gedas V <gedu...@gmail.com>
Sent: Sunday, October 19, 2025 4:34:13 PM
To: ham...@googlegroups.com <ham...@googlegroups.com>
Subject: [HamSCI] VLF Dawn Chorus Capture, Oct 3, 2025

 

Hello group. I wanted to share my first dawn chorus capture. By dumb luck I was up at 4 AM watching a very corny sci-fi movie while monitoring VLF. Out of the blue starts the sound of hundreds of chirping birds. The event lasted about 20 minutes and not anything I will soon forget. 73 Gedas W8BYA EN70JT (NE Indiana).  Below is a portion of the capture which I put on YouTube.

https://www.youtube.com/watch?v=u_N83W_4vWQ&t=32s

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[Gedas V]

Hi there Gordon. Nice to see you here as well as up on 10 GHz hi-hi.  So the setup is quite simple. The antenna is something that I could have made myself but due to too many other to-do projects I decided to just buy one ready made. It is a unit from Stormwise, one of their affordable models. It has a response from about 10 Hz to 10 kHz and provides an audio output. There is no "detector" or mode as such. Think of it as a non-tunable receiver with an audio passband from near DC up to 10 kHz to maybe 20 kHz. I fed the audio output into SL software via a soundcard where I enabled a 60 Hz (and harmonics) filter to be able to hear the weaker tweeks and chorus. Ideally I need to be several miles away from any powerlines as the 60 Hz PL signals slaughter these weaker signals. But I do not have that option and make the best of DSP based notch filters etc.  73 Gedas W8BYA

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[Gedas V]

Oh, one thing I forgot to mention when you asked what frequency.....you can see the freq along the Y-axis on the right side of the capture. The chorus signals are all the wavey nebulous clouds that come and go below 3-4 kHz.

On Sun, Oct 19, 2025 at 6:00 PM J. Gordon Beattie, Jr. <w2t...@gmail.com> wrote:

To view this discussion visit https://groups.google.com/d/msgid/hamsci/DM3PR84MB3660FBCD9E07BC776BD52F99ABF4A%40DM3PR84MB3660.NAMPRD84.PROD.OUTLOOK.COM.

[Darrel Emerson]

Which Stormwise unit did you use?

73

  Darrel g3sys

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[ghby...@k9trv.org]

It sounds like it is the ‘baseband VLF radio receiver’ listed as costing $29.95 plus $15 shipping.  It’s called VLF receiver Unit in the right side band of pictures.  Sorry, it looks like the website isn’t designed to give a direct link for use by others…  https://stormwise.com/index.html

 

73

George K9TRV

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[Gedas V]

No it was not that unit. I just spent 15 minutes looking over every antenna available and could not find it. The site (IMO) is very poorly structured which is a shame. In any event I suspect it is a high-Z e-probe antenna fed into a high-z op amp circuit that then outputs an audio signal that can be fed into a sound card or headphones etc. Sorry I could not find the exact model for you but definitely not the unit mentioned by ghbyrkit. 73 GL Gedas W8BYA

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