VLF-ULF Detection

VLF/ULF Detection

One of the many tools in the field researcher's toolbox is the Electromagnetic field meter. It is quite a useful tool, albeit misused at times. One of the many faults with them however is the inability to explicitly show the frequencies and strengths of the field being measured.

However, with the advent of Software Defined Radio(SDR), we now have the ability to view the entire band of ELF/VLF simultaneously. This article details some of the specifics to utilize this technological advance in paranormal field research.

Hardware Required

The essentials for the SDR is the processing power (ie a laptop), the input device (Antenna), and the software to decode electromagnetic energy into something we can look at, and record.

The core of the system is the processing power. This can either be a complete receiver, that interfaces with a computer, or has it's own display. Most of the single purpose units lack the ability to view the entire band, as well as recording it. However, since a number of the devices are in and of themselves a SDR, this can possibly be modified.

However, in this discussion, I'll cover utilizing a laptop as the SDR. For ELF/VLF, this can easily be done with nothing more than the sound card built into your computer. The sound card acts as an ADC (Analog to Digital Converter), that has a sample rate from 0-44KHz (Usually). Higher end sound cards can reach in upwards of 96KHz, and sometimes even 128KHz. The most basic of the sound cards which got to 44KHz will be able to detect frequencies up to 22KHz. This is due to the requirement of the oscillator frequency must be double the frequency being detected. Our oscillator here is the sound card's sampling. Higher frequencies can be detected with higher rate sound cards.

The antenna should be as long as feasible. This is due to the optimum antenna lengths are dependent on the frequencies being detected. For the ELF/VLF range, the optimum antenna would be approximately 60,000M long. Since the optimum antenna is hardly obtainable, as long as possible (Excess of 200M) is the best. This would be connected to the PC via a stereo headphone connector, with the antenna connected to the Left input.

Software

The software can be one of several options. The simplest of them to use is the SAQ VLF Receiver. Not very many features to it, but very simple to have up and running.

The other option is SpectrumLab, which has many options, to include sample rate, input/output frequencies for the oscillators, etc. It also has a preloaded template for setting up to listen to ELF/VLF.

Both require Microsoft(tm) Windows (tm) to operate, but can run on very modest systems, with minimum CPU and memory requirements. A full set of manuals are available for both on their respective websites.

Comparison and Contrast to standard EMF Meters

The SDR is much more useful than the standard EMF meters thanks to the ability to view the entire spectrum, rather than just reading what the peak measurement of the sweet spot for the EMF meter of choice. Also, it gives a whole view, which would allow analysis for harmonics, etc. Additionally, it can also let you know exactly at what frequency and strength the fields are at.

However, one fault is largely dependent on the portability of the computer, and antenna. One method of deployment that I have used has been running the antenna lead throughout the house on the floor. This gives a wide-area view of the fields in the house, however, it can not locate point sources. Since there is no software currently written for a PDA or mobile phone type platform, the portability of the computer weighs heavily into this.

External Links

Contributors

Author: Corey Reichle
Other Contributors: None