Hi everyone! Here's another instructional post on how to find someone who is using a radio. That is, how to locate the source of a radio transmission. The reason why I am doing this is two-fold: it might come in handy, sure, but more importantly, you need to see how easy it is for someone to do this to you.
This works on all frequencies, all modes and at all distances (of course, the closer you are, the more accurate this will be).
The Loop Antenna
To effectively triangulate, you will need a loop antenna.
If you used your camera and took a picture of the side of a loop antenna, it would look just like a metal stick. And as far as radio waves are concerned, it is a metal stick, and radio waves are "flat" (picture the sine waves you see on a screen, and then imagine what they look like coming toward you). This is why antennas are long and metallic. And so, radio waves have no problem with traveling into the side of a loop antenna.
The face of a loop antenna, not so much. And this is precisely why a loop antenna is the antenna of choice for triangulating. When the face of the antenna is pointing directly at the source of the radio signal, the signal drops to ZERO. And it does this very markedly. That zero signal is very brief as you turn the antenna, so it is also very accurate.
The thing is, though, is that the antenna has two "faces", so to speak. Look at the picture above. That's a face. Rotate it 180 degrees. That's the other side, or other "face". I call it "heads or tails". Let's say you are using this to receive your favorite rock station, and you have the face pointed so that the signal drops to zero. In which direction is the radio station? Heads? Or tails?
If you do this process just 1 time, you have a 50/50 chance of heading in the right direction as you try to find the station.
Triangulation
So, we do it 3 times - 2 times shows you where they are, and the 3rd is for precision. So, armed with a radio (and most have a signal strength meter built-in), a loop antenna, a map, and a compass, let's get started!
Let's use a map of Atlanta, GA as an example:
Step 1: Tune into the frequency that the station in question is on. Whenever they transmit, rotate your antenna while looking at the signal meter. As soon as it drops to zero signal, use your compass and measure the azimuth of the antenna. Remember, it points "both ways", so you will need to reflect this on your map by continuing the line all the way across the map.
Step 2: Move to a different location, and repeat the process. You will have two intersecting lines.
Step 3: Move to a different location (again), and repeat the process (again). If your measurements are dead-on accurate, you'll have 3 intersecting lines. If not, you'll end up with a triangle that tells you they are somewhere inside the triangle.
Now - if you just happen to have two other buddies who live in different parts of town, and the ability to talk to each other on a different frequency, this can be figured out in just under a minute. And of course, the more lines you draw, the more accurate the result will be.
This works on all frequencies, all modes and at all distances (of course, the closer you are, the more accurate this will be).
The Loop Antenna
To effectively triangulate, you will need a loop antenna.
If you used your camera and took a picture of the side of a loop antenna, it would look just like a metal stick. And as far as radio waves are concerned, it is a metal stick, and radio waves are "flat" (picture the sine waves you see on a screen, and then imagine what they look like coming toward you). This is why antennas are long and metallic. And so, radio waves have no problem with traveling into the side of a loop antenna.
The face of a loop antenna, not so much. And this is precisely why a loop antenna is the antenna of choice for triangulating. When the face of the antenna is pointing directly at the source of the radio signal, the signal drops to ZERO. And it does this very markedly. That zero signal is very brief as you turn the antenna, so it is also very accurate.
The thing is, though, is that the antenna has two "faces", so to speak. Look at the picture above. That's a face. Rotate it 180 degrees. That's the other side, or other "face". I call it "heads or tails". Let's say you are using this to receive your favorite rock station, and you have the face pointed so that the signal drops to zero. In which direction is the radio station? Heads? Or tails?
If you do this process just 1 time, you have a 50/50 chance of heading in the right direction as you try to find the station.
Triangulation
So, we do it 3 times - 2 times shows you where they are, and the 3rd is for precision. So, armed with a radio (and most have a signal strength meter built-in), a loop antenna, a map, and a compass, let's get started!
Let's use a map of Atlanta, GA as an example:
Step 1: Tune into the frequency that the station in question is on. Whenever they transmit, rotate your antenna while looking at the signal meter. As soon as it drops to zero signal, use your compass and measure the azimuth of the antenna. Remember, it points "both ways", so you will need to reflect this on your map by continuing the line all the way across the map.
Step 2: Move to a different location, and repeat the process. You will have two intersecting lines.
Step 3: Move to a different location (again), and repeat the process (again). If your measurements are dead-on accurate, you'll have 3 intersecting lines. If not, you'll end up with a triangle that tells you they are somewhere inside the triangle.
Now - if you just happen to have two other buddies who live in different parts of town, and the ability to talk to each other on a different frequency, this can be figured out in just under a minute. And of course, the more lines you draw, the more accurate the result will be.
