Tradecraft Training — Electronic Spying by Mentor Publications

Electronic Spying

Published by Mentor Publications
Year: 1976
Pages: 56
Available on Amazon

I love estate sales. My wife and I go to them whenever we can. You never know what you’ll find. You can usually get a good feel for what kind of stuff you’ll find as people tend to surround themselves with items related to their passions and a lot of it. It works out great when their passion is also your passion, but that wasn’t the case on our last outing. Other than a few items that piqued my interest there wasn’t much. As I was finishing paying for the few baubles in my hand I turned to face a stack of books. On top was this aged yellow booklet entitled Electronic Spying. I picked it up and held it up to the proprietor of the sale and asked how much? “Take it, it’s yours” was their response. As I got back into my car, into the passenger seat, I opened the booklet to see what this odd publication was about. It was as the title suggested, a booklet on secretly listening on private conversations with the use of electronic devices. Based on the items I saw at the sale, I never imaged I would come across a publication so bizarre.

Electronic Spying by Mentor Publications covers devices and methods used in electronic surveillance. Published in 1976 it was just one of the many unconventional publications that Mentor Publications distributed. Advertising in the classified sections of magazines like the Electronic Technician/Dealer and Radio Electronics, Mentor Publications offered a variety of unusual and somewhat questionable technical manuals for the anti-government survivalist of the 1970s and beyond.


The publication is low-budget, a real cut and paste job with high contrast photos, large sections of text with no columns, and hand-drawn diagrams. The content is somewhat a how-to manual on proper techniques for deploying and utilizing surveillance equipment of that era as well as understanding the equipment involved. Topics like wireless transmitters, receivers, recording equipment, ‘hard-wired’ techniques, miscellaneous procedures, and ‘wiretapping’ telephones are all covered in this 56-page booklet. All or most of the information on these subjects are way out of date with today’s technology but a great resource for roleplayers playing an espionage game in that era.

In the past, I’ve covered espionage literature (100 Deadly Skills: The SEAL Operative’s Guide to Eluding Pursuers, Evading Capture, and Surviving Any Dangerous Situation) and inspirational sources (Finding Inspiration for Espionage Games – SpyCast Podcast) but none have been able to provide me with tradecraft from the 1970s like Electronic Spying. The information that I’ve learned from Electronic Spying will go a long way in adding flavor to my espionage role-playing game.

The booklet opens with an overview, “basic methods, and equipment to steal industry secrets, gather evidence against otherwise ‘evasive’ criminals, and trap adulterous wives and husbands.” The intention of the publication is to provide information only. It is not meant to be a training manual with detailed schematics to create your own devices. Since there is no author credited with the publication, the origin of this information is unfounded. But based on the insightful information and the examples given, I believe the unnamed author to be an experienced operative who has put these techniques and practices to use.

In the first section of the booklet “Wireless Transmitters,” it covers basic examples of wireless listening devices. Small concealable devices with long antenna wires hiding behind paintings or inside lampshades, the type we’ve all seen in cop and spy movies. The booklet instructs on the proper placement of such devices to provide optimal coverage. It also covers the device’s longevity based on its range. The farther the device transmits the quicker the internal battery is exhausted. A device tuned to broadcasting two-mile can operate for ten hours while a device set at 500 yards would last 96 hours. These devices are one and done. When an operative deploys these kinds of bugs they are considered “lost”. Attempting to retrieve a listening device is dangerous; too risky to the mission. Unless the operative has an unlimited budget, spending a lot of money on creating a device that broadcasts across town is cost-prohibitive. Most listening devices are handcraft by a trustworthy electrical technician for a specific job that is inexpensive and disposable.

Once a listening device is placed the operator listens in via broadcast radios waves with the proper receiver. Receivers aren’t all alike. You can’t listen to an AM station on an FM receiver. Operators use receivers specially tuned to an inaccessible crystal-controlled frequency. The booklet demonstrates the modification of a store-bought transistor FM radio. A commercially purchased FM radio only uses part of the FM frequency spectrum. 88 to 108 Mhz frequency range is the national standard for commercial broadcasts. Most operatives would use the spectrum below 88 Mhz since 108 Mhz and above “Air Band” is for aircraft communications. Bugs can use the higher frequencies but run a greater risk of being casually intercepted. Remember these are unsecured radio waves flying through the air that can be heard by anyone with a properly tuned receiver.

Time is money and an operator, unless it’s required, does not need to listen in all the time. A recording device is used with the receiver to monitor activity. In the mid-1970s tape recorders were used, small handheld reel to reel or cassette recorders. These small recorders were small enough to be concealed in a parked car within the range of the bug. An operative would only need to periodically swap out its tape. To increase the time in visiting the recording device the operator had a couple of tricks they could use. One trick was to tune the carrier switch on the receiver to only sense the radio carrier wave instead of the audio signal. The operator could then adjust the volume so when the audio signal appears on the radio carrier wave the recorder would click on. Another trick used a recorder with a VOX device. A VOX unit is calibrated to the rooms ambient noise and any noise above it switches the recorder on, usually only losing the first syllable of a spoken word.

For long term surveillance, ‘Hard-Wired’ bugs are used. The term ‘Hard-Wired’ means that a listening device uses the power from another device, a parasite. The device like a television set, lamp, or toaster which is always plugged in is key. The ‘Hard-Wired’ device does not need to be turned on for the listening device to be active. It only requires that the item be plugged into an electrical socket and receiving electrical current. These types of devices are placed in a target’s home in several ways. An operator could remove an item from the premises without the knowledge of the target and quickly return the bugged item as quickly as possible or it could be a gift presented to the target. Either way, the unit must be plugged into an active electrical socket for it to work.

Hardwired devices need not be complex or wireless. A simple tiny microphone can be used in a space where it’s wires are easily camouflaged and run to an adjacent room to the receiver. An example is given in the booklet. A shady car dealer uses a listening device to spy on his customers. A small microphone is installed in a wall phone jack in the office of the dealer. Its wires are hidden with the normal phone line into the wall that leads next door to a storage room. The car dealer excuses themselves and gives the buyers “privacy” to discuss the offer while he quickly moves next door to listen in on the receiver. The cost of setting such a listening deceived is very low but can be easily traced by following the wires.

Telephones are the most commonly bugged devices in t.v. and movies. The booklet demonstrates how it is accomplished. An operator who uses and Infinite Transmitter (illegal device) can turn a phone receiver into a “hot mic”. A phone wire has four wires which can be easily switched out with a six wire phone cable that looks the same. The extra two leads on the wire are used to connect power the phone’s receiver even when the receiver is on the cradle. The operator can then call into the ‘hard-wired’ phone from anywhere in the world without it activating ringing on the target’s end which activates the Infinite Transmitter, turning the receiver into a “hot mic”. This is not a wire-tap. It will only pick up the conversation in the room and not a conversation on the phone. If the receiver is picked up by the target the operator must quickly severe his connection or risk being discovered.

Since we are talking about phones, the booklet has a section on wire-tapping. To wire-tap a phone you are basically splicing off from someone else’s line. This can be done at the top of a telephone pole or at the target location where the phone service box is located. The booklets show several methods of wire-tapping. Wire-tapping is illegal when not properly authorized. Illegal wire-taps are at the risk of being discovered in several ways. A phone draws current from the phone lines which can be monitored by the phone company. If a parasite device is used, the phone company could detect the extra power drain leading to an inspection of the line. Another way of getting caught is if the tap occurred at the target’s service box. A service box is comprised of many little pegs or leads that connect individual lines to the phone company. A couple of jumper wires can provide access to another phone line to another monitored line. A phone technician called to work on a jumped service box would immediately spot the illegal activities and report it to the proper authorities. The booklet offers an expert workaround solution to conceal the illegal hook up with electrical paint. Wiretapping a phone can be a hard-wired operation or wireless. The booklet provided many different methods.

I’d have to say this is by far the strangest item I have ever found at an estate sale, but I’m glad I found it. With the knowledge, I’ve learned from its pages, I have an intimate understanding of eavesdropping equipment for the mid-1970s. I also have a metric of the cost of such devices, since the author was kind enough to provide the prices of some of the devices shown and the cost of services to have them created or altered. Though utilizing any of these techniques or devices without proper authorization is illegal (and outdated) the information I’ve gained can go into embellishing any roleplaying game where electronic surveillance is used for that era. Electronic Spying is the missing tradecraft sourcebook on eavesdropping that I’ve been searching for my espionage role-playing games.

~Stephen Pennisi

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