The averaged spectral matrix will be used to determine the complete set of wave parameters, including Poynting flux, polarization, planarity, and k-vector direction. Spectral matrix components will be averaged to obtain 1 second time resolution and frequency resolution better than 10%. Together, these five wave components will be used to calculate real and imaginary spectral matrix components using real-time fast Fourier transforms calculated in an onboard FPGA. The CANVAS VLF receiver will observe five components of VLF waves in the 0.3–40 kHz frequency range, using three orthogonal magnetic search coils deployed on the end of a 1-meter carbon fiber boom and four deployable electric field antennas operated as two orthogonal dipoles. This paper describes the design of a VLF receiver for the Climatology of Anthropogenic and Natural VLF Wave Activity in Space (CANVAS) CubeSat mission, designed to make continuous observations of VLF waves in low-Earth orbit originating from lightning and ground-based transmitters. That’ll be at hyperdata.Very low frequency (VLF) waves play an important role in controlling the evolution of energetic electron distributions in near-Earth space. I’m in the process of setting up a site to place all my material. But living in a seismically active part of northern Italy led me toward this stuff. I’m Danny Ayers, usually a (Semantic) Web developer/consultant. The key, novel, intuition here is that Deep Learning techniques may expose patterns in the wildly noisy signals of the Earth. The hard part is the idea of providing useful earthquake prediction. Effectively Internet of Things (IoT), better still, Web of Things (WoT) subsystems.
VLF RECEIVER DESIGN SOFTWARE
The aim of this project is to develop inexpensive hardware and software capable of capture and analysis of radio and seismic data.
It has been observed that major seismic events may be preceded by anomalies in natural radio signals, notably those <20kHz (the ELF/ VLF frequency bands). I must admit, it does have a bomb-like appearance! It spent the rest of the night under an overturned flower pot with the VLF antenna sticking out the little drain hole in the bottom.“.Īnother very promising site I ran across, have still to read, is Larry’s Very Low Frequency Site. That turned out to be a questionable location, by the way! Not only did several neighbors become alarmed by it, but a couple of police officers also spotted the thing. “ The antenna was horizontal and near the ground under my truck for this recording. Here the author bends a baby monitor transmitter, replacing the mic with a VLF preamp. houses, computers… Which is a pain if you want to record/analyze the signal. The major problem with VLF reception is interference noise, so ideally you want to situate the receiver a long way from sources of that – eg. One piece of utter genius jumped out at me. It features a variety of simple receiver designs. This page is notable : VLF Natural Radio Reception at. While vlf.it is the site for all things Radio Nature, I did stumble on some material I hadn’t seen before. I found what I was looking for in the first, but am pleased I didn’t close the others.
When I was looking for the gain requirements yesterday, I opened a bunch of the results in browser tabs. Hmm, gain of 1500, that’ll be tempting to stability problems. I also need to check roll-off at the frequency extremes (call it 20Hz & 20kHz). I can figure out the gain bits from there, and simulate. There’s a feedback resistor change in my near future.įirst though I reckon I’ll draw up the circuit as it stands (in KiCAD). Signal is of the order of microvolts, their overall gain is x1500 – rather more than I’ve allowed for so far. It doesn’t have the schematic – I expect it’s one of their INSPIRE models.
VLF RECEIVER DESIGN PORTABLE
But I’d forgotten a key consideration, how much overall gain the thing should have.Ī quick google later, found this rather nice poster on NASA’s site, “ Building and Testing a Portable VLF Receiver“. I’ve already soldered up the input & filter stages, yesterday breadboarded the output stage – an amplifier to drive a little speaker/headphones.
Some filtering is desirable to limit the bandwidth and cut the noise of mains hum. For an electric field receiver all that’s essentially required is a whip antenna and a high input impedance, high gain, audio frequency amplifier. I’m doing a little more on a simple handheld VLF receiver I’ve been working on.