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RTL SDR Spectrum Analyzer for Detection of Reradiated and Emitted Radio and Microwave Energy from Humans

User Guide

Here's the user guide described here with images:

Reradiated or emitted radio or microwave energy can be detected based on the fact that there should be an increase in signal strength when you're near the antenna.

You should place the antenna for the rtl sdr on your desk, near your computer or if you're using a yagi antenna, it should be pointing to where you work at your computer and it should preferably be reasonably near.

The rtl sdr spectrum analyzer then determines when your near your computer based on keyboard and mouse input.

If a signal often increases in strength when your near the computer, and so also near the antenna, it could be because it's being reradiated or emitted from you.

So this is how it determines that a signal increased in strength if it's from you.

However, signals also change in signal strength themselves, because they're used for transmitting information and they do that using changes in signal strength.

So to determine whether a signal is changing in signal strength because of you, this code system averages the signal strength over a longer duration, since this varies less.

So the noise is reduced after averaging, showing signals that are essentially or almost hidden in the noise.

Where there's a signal that seems to be stronger when you're near, it will be detected as an interesting signal.

Based on how often signals are detected as an interesting signal, they will also be placed in a leaderboard list of signals.

So this list is for signals that are most often detected as interesting signals.

Another list determines the ranking of frequency ranges (of 1 MHz bandwidth) based on where the signals within that range are on the leaderboard.

Frequencies from these lists are then chosen for further analysis.

Because a spectrum analyzer can only analyze a small section of bandwidth at a time, especially with the rtl sdr only having around a 2 MHz bandwidth, it takes a long time to analyze a large frequency range, 1 frame of data for a 400 to 500 MHz range takes a while.

So the most likely reradiated signals from the leaderboard list are further analyzed. The rtl sdr being set to analyze just the 1 MHz range that the signal is in. This means that it can get many frames of data in a short duration.

It also let's us do what's called a transition analysis on that frequency range.

This is when someone is further away from the computer and then returns.

If such a frequency range is being analyzed when they return, and because many frames of data are being acquired for that range, the signal strength for all the frequencies in the range are analyzed for a change in signal strength.

The frequency or frequency range's change in signal strength is graphed for a duration of 16 seconds, 8 before pressing a key or moving the mouse and 8 seconds after.

The signal strength before and after returning to the computer are averaged and compared.

If it's found that a signal is often producing an increase in signal strength for these transitions then the code system determines that it could be a reradiated or emitted signal and lets us know so that we can do a more detailed analysis on it.

Graphs and controls are then shown for this. These graphs are the strength, strength gradient, most recent and averaged transition graphs.

The “record” button can be selected to determine whether the signal's strength and it's gradient graph show increases when near the computer and decreases when further, this could be because it's a reradiated or emitted signal.

The “Check Far to Near Transition Strength Increase” button allows us to do a transition analysis on the signal and also the 1 MHz frequency range that it's in.

This is achieved moving further away for 8 or more seconds and then returning to the computer and pressing a key or moving the mouse, so that the code knows when we're near.

The transition signal strengths will then be shown on the transition graphs, the averaged for all the previous transitions for that frequency or frequency range and the most recent transition.

If the transition signal strengths are stronger on the right side, so after you return to the computer and are near the antenna, and the percentage increases are greater than 100%, then it could be a reradiated or emitted signal.

Do this and the previous test at least several times to be sure of such signals.

You can do this for the frequency and the frequency range using the "Check frequency" and "Check frequency range" radio buttons.

When you close the form, the automated analysis of the original entire specified frequency range will resume.

There's a lot of other functionality that this spectrum analyzer code system has, although this essentially describes the automated system for the detection of reradiated and emitted signals.

If you use this system sufficiently you should at the very least detect a reradiated frequency or frequency range, because it's a scientific fact that all humans have them.

Finding your reradiated frequency range could be very important for determining how that frequency range is being used and whether there are transmissions that could be causing unintentional (electrosensitivity) or intentional biological effects.

Installation Instructions

You need to install the rtl sdr dongle according to this guide:

If you get a "the specified module could not be found" error then you probably also need the Microsoft Visual C++ 2010 Redistributable Package (x86):

If you need to buy the dongle I would also recommend

Additional Information

You should also read this research paper/thesis for more details on how to use the rtl sdr spectrum analyzer and how I detected the signal that I mentioned:

The code uses the librtlsdr library to transfer data from the device:

The description for this project is here:

The libusb library code is also used to communicate with the device using USB:

So the code for libusb-1.0.dll and rtlsdr.dll is available from there if you require it.
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