Robert Jones

This essay might be of special interest to writers of detective and mystery stories who would like to enrich their stories by providing their readers with a gift of some extra details. It might also be of general interest to many other readers. The two opening, example stories are a bit outside the realm of forensics, but they serve as a preface to the communication technology involved in forensic situations, for example, terrorism, smuggling and assassinations, where secret communications over long distances play an important role.

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Martin’s hand trembled slightly as he removed a radio transmitter hidden beneath a floorboard in his apartment and began to tap out an encoded message. It was early winter of 1943, and he was an English secret agent sent to France to gather critical military information and radio it to a military receiver in England.

Vehicles having rotating, directional antennas on their roofs and being manned by German soldiers were prowling in the general area of Martin’s apartment, searching for radio signals. The antennas on three of the vehicles, each at a different location, had stopped while aimed in the direction from which the strongest radio signal was being received, that is, in the direction of the source of the message being transmitted by Martin. Imaginary lines extending in the direction pointed to by each antenna intersected each other at a point that was very close to the transmitter. Within minutes, the door to Martin’s apartment burst open, and he was faced by three armed men in German military uniforms. It was a long time before he saw his home in England again.

More recently, an American secret agent on a mission similar to Martin’s transmitted an encoded radio signal to a receiver in the United States from a location in an unfriendly country. He, however, used a directional antenna aimed at a location in the sky and his message had been prerecorded before being transmitted. Receivers placed in strategic locations by the unfriendly country to intercept such messages did so. The direction from which the signal had arrived at the receivers might have led to another door being burst open, but the transmitter of the message would not have been found behind it. WHY NOT?

Many of us have seen trails left by meteors (also known as shooting stars and falling stars) as they zip through dense layers of the Earth’s atmosphere, their passage resulting in their being heated to a point of incandescence. Fortunately, most meteors are quite small–comparable to the size of a grain of sand–so we need not wear helmets when we venture outdoors. Many, many more small meteors enter the atmosphere than do large ones; and even fewer are large enough to survive a passage through the atmosphere without burning up. Those that do survive and land upon the Earth’s surface are known as meteorites. Meteorites having a size between that of a sand grain and a boulder are sometimes referred to as meteoroids (meaning meteor-like).

Readers might remember that, in their natural state, atoms have an equal number of positively charged protons and negatively charged electrons, making them electrically neutral. The numbers of electrons and protons distinguish atoms of one basic element from atoms of all other elements. Gaining or losing electrons upsets the neutral balance of electric charge, leaving the atom in a state known as an ion. The passage of meteors knocks negative electrons from atoms, transforming them into positively charged ions and, as a result, leaves a trail as long as 12 miles of free electrons and ionized particles in their wake.

A radio signal usually travels in a straight line known as a “line of sight.”  Since the surface of the Earth is curved, the distances across which transmitted signals can be successfully received are limited.   Transmitting and receiving antennas are placed atop tall buildings and towers to extend such distances. Interestingly, meteor trails can also be used to extend the distances radio signals can travel between transmitters and associated receivers. Radio, television and radar signals of certain frequencies can be reflected by the electrically charged trails.  The trails are sometimes higher but are usually detected in the upper atmosphere, between 50 and 75 miles above the Earth’s surface. With reflectors at such heights, signals reflected by meteor trails can reach receivers more than a thousand miles away. 

Meteor trails occur sporadically, and their trails usually last for only a few seconds and rarely for a few minutes. so information is transmitted in short bursts. A message in Morse code, for example, can be recorded, sped up by a factor of about 200, transmitted and decoded after being received. An estimated 1,000,000,000,000 meteors (more than a ton) come to visit our atmosphere every day, thereby providing a significant amount of reflective trail material.

Regarding the second opening, example story, a result of a radio signal being reflected between a transmitter and a receiver is that, since the signal does not follow a direct, predictable path, the location of the transmitter could not have been accurately determined. This is why the transmitter would not have been found behind the aforementioned door.

Where there is satellite coverage, of course, messages can be more dependably relayed to receivers even farther away; but meteor burst communication provides a means of radio communication that can be used where no other means is available.

As a shuttle astronaut recently mentioned, human waste was jettisoned from shuttles to burn up in the atmosphere. As a consequence, that brilliant trail you might once have witnessed may have been the remains of something far less less exotic than a meteor.

ADDITIONAL INFORMATION:

The advantages of meteor burst communications also include its inherent interception, detection, antijamming and nuclear survivability characteristics.

Atmospheric meteors move at a bare minimum rate of some 25,000 mph but can exceed 100,000 mph.

Some 50 tons of dust and meteorites are added to the estimated 6.58 sextillion tons of the Earth every year.

Meteor showers occur when the Earth passes through space debris. The showers provide fruitful viewing for several days. The dates of major meteor showers can be easily found on the internet. (See, for example, meteorshowers.com.)

For those interested, broadcasts of live meteor burst audio received at Roswell, NM are made available by Spaceweather.com at the following locations:\

http://spaceweatherradio.com/index.php

or
Space Weather Radio