Spy Review

This is the first article in a series relating to making your own homemade spy gear. Sometimes, it’s not possible to find exactly what you want, or indeed at a price that you can afford! So these brief articles are my tips for making your own surveillance devices, without breaking the bank.

In this article, I’m going to talk about a spy phone (aka bug phone) detector device. The kit used to make the spy phone detector is easily and cheaply available from Quasar Electronics (a UK company), but easily available in the US too.

The kit is what’s called a Telephone Pickup Amplifier, which is a sensitive electromagnetic suction cup, connected to an amplifier and speaker. The device is designed to amplify the signals detected from the back of the earpiece of a common house-hold telephone, so that other people in the same room can hear the conversation on the telephone. I’m sure that you’re thinking that its a peculiar device to have, and I’d have to agree with you!

OK, so how is this used to detect spy phones then? Well, the telephone pickup device is very sensitive to electromagnetic signals, sensitive enough to pick up the weak signals on a standard telephone earpiece. If you’ve had your mobile phone near a radio or indeed a land telephone, you’ll have heard the “duh duh dut” sounds through the earpiece or speakers when recieving a text message or call on the mobile phone. Those sounds are caused by the electromagnetic radiation from your mobile phone, which induce a small current and therefore signal in the radio or landline. This small signal from the mobile phone is stronger than that of a standard telephone earpiece, and thus easily detected by the pickup amplifier!

So, basically we’re using the pickup amplifier to detect the electromagnetic signals generated by a mobile telephone; and mobile phones form the basis of all spy phones. Therefore if a spy phone is in use (i.e. in listening mode), this kit will reveal its presence as “duh duh dut” sounds on the speaker of the amplifier. This device is more sensitive to spy phones than a standard bug detector, as bug detectors are rarely sensitive enough around the frequencies that mobile phones use (900MHz, 1800MHz and 1900MHz). The pickup amplifier detects generic electromagnetic signals, and a mobile phone spits out quite a lot of electromagnetic radiation.

The Telephone Pickup Amplifier is inexpensive, and if you’re handy with a soldering iron, it costs just £13 plus postage to build it yourself. If you buy it ready-assembled, it costs £20.95 plus postage. The kit contains all components, the circuit board, the suction cup ‘microphone’ coil, a battery holder for 4xAA batteries and a speaker. It does not contain any enclosure, so you’ll need to be creative with a case. However, most cases cost less than £5 on eBay or in Maplin.

So there you go, the first in a series of cheap homemade spy gear! More will appear on Spy Review in the near future!