[TangerineSDR] VLF-RX tools

Jonathan emuman100 at gmail.com
Wed Mar 10 22:12:03 EST 2021

Hi Tom,

Thank you for looking at the documentation for vlfrx-tools! I'll list some 
useful utilities included in vlfrx-tools to try to illustrate how useful 
they can be. A utility can be written to convert to DigitalRF/HDF5, 
however, vlfrx-tools does not normally generate IQ data.

For others on the list, the vlfrx-tools documentation is 
available at http://abelian.org/vlfrx-tools/ and this also includes the 
source code. Also, for the others on the list, I'd like to make the 
argument that vlfrx-tools is advantageous because of its useful toolset in 
analysis and post-processing of both natural radio, amateur radio in the 
VLF band, and VLF transmitters. Such tools don't exist (to my knowledge) 
for formats like DigitalRF. Since vlfrx-tools is such a diverse and 
usefull toolset that already exists, it's advantageous to utilize it in 
post-processing on the PSWS database to make available SID events, 
whistler and chorus events, and lightning location data, just to name a 

vtblank - an impulsive noise blanker that removes sferics and other 
impulsive noise from the VLF spectrum. It's useful in studying VLF 
transmitters and especially useful for VLF QSOs.

vtam - used to extract the magnitude of a non-stationary signal like a 
sferic. You can examine the timing of sferics, whistlers, and the edges of 
timing signals like WWVB.

vtpolar - generate a polar plot movie of a triple axis VLF stream. This 
allows you to see the bearing of incoming VLF signals like whistlers. 
Please watch the movie in the documentation!

vtsid - automatically  detects sudden ionospheric disturbances with VLF 
transmitters like NAA. It generates a plot and a data file. The extraction 
utility can extract records from that data file.

vtevent - automatically detects whistlers and chorus and generates a 
spectrogram plot, data file, and audio file of the event.

vttoga - creates time of group arrival data from sferics the incoming VLF 
stream or a file.

vtspot - used to generate lightning location data from vttoga data from 
VLF receivers around the world. The PSWS database can provide lightning 
location data using a network of receivers.

vtping - used to detect meteor ping.

vtwrite - writes a VLF stream, either from a ring buffer or network 
socket, to file for storage.

vtread - reads a .vt file into a ring buffer or network socket.

vtraw - extract raw audio froma VLF stream. This also removes the 

vtwavex - extract a wav file from a VLF stream. This also removes the 

These are just some examples of useful utilities of vlfrx-tools. A utility 
to convert a .vt file to DigitalRF/HDF5 can be written (however, I cannot 
support that). Also, vlfrx-tools does not generate IQ data normally. But, 
with such a toolset, so much can done. I would hope this convinces some of 
those who may be skeptical. In any case, I urge you to look at the 


On Wed, 10 Mar 2021, Tom McDermott via TangerineSDR wrote:

> Date: Wed, 10 Mar 2021 12:07:26 -0800
> From: Tom McDermott via TangerineSDR <tangerinesdr at lists.tapr.org>
> To: TAPR TangerineSDR Modular Software Defined Radio
>     <tangerinesdr at lists.tapr.org>
> Cc: Tom McDermott <tom.n5eg at gmail.com>
> Subject: [TangerineSDR] VLF-RX tools
> Hi,  I don't have Jonathan Rizzo's direct email, so sending this to the
> list.
> We talked a bit about the VLF receiver on the last conference call, and the
> VLFRX tools.
> I'd like to email with Jonathan directly.   It appears those tools have the
> ability to
> read from a file (and thus in Linux from a named pipe).  Gnuradio can write
> to a named pipe
> as well to DigitalRF (HDF5).   Perhaps this may provide a mechanism to
> hook the receiver both to the Tangerine archiving method as well as to
> -- Tom, N5EG
> n5eg at tapr.org

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