The radio broadcast network provides sound quality comparable to VHF broadcasting. Having a computer or cell phone with a voice recorder function, such broadcasts can be recorded for your own needs.
Instructions
Step 1
The quickest way to record a radio broadcast is to bring a microphone connected to your computer to the broadcast loudspeaker. In the same way, you can make a recording using a cell phone. But its quality will turn out to be low. In addition, there will be extraneous noises on the recording (for example, steps, conversations).
Step 2
A much better recording can be done like this. Open the subscriber loudspeaker and connect the two wires to its speaker (connected to the secondary winding of the transformer). Apply the signal to the microphone input of the sound card through a capacitor with a capacity of 0.01 to 0.5 microfarads. To record on a cell phone, you can take a wired headset, remove the microphone from it and send a signal through the same capacitor to the contacts to which it was soldered.
Step 3
The three-program receiver allows you to record transmissions of all three channels (low frequency and two high frequency). For this, he has a socket with five contacts. The middle contact is common, and the right or left (depending on the year of manufacture of the device) is the output. Some receivers have two output jacks instead of a five-pin connector: the bottom one is common, the top one is signal. Since the transmission wiring is grounded, the signal from such a jack should be fed to the computer through a transformer with an input impedance of about a kilo-ohm and a transformation ratio of 1: 1 for safety. The headset of a cell phone (see above) can also be fed directly, provided that the device is not connected to a charger, or to a computer, or to anything else.
Step 4
In the absence of a loudspeaker or a three-program receiver, the signal of the first program can be recorded using a transformer that lowers the voltage by 10-20 times. Connect its primary winding to the broadcasting network, and apply the signal from the secondary to the microphone input of the computer through the capacitor, the capacity of which is indicated in step 2.
Step 5
The signals of the second and third programs can be removed using the detector receiver. To do this, it will have to be tuned to frequencies of 78 and 120 kHz. It should be connected to the broadcasting network by placing a capacitor with a capacity of several hundred picofarads in each of the input wires. They must be rated for a voltage of at least 400 V.
Step 6
Connect to the microphone input of the sound card using a two-pin jack plug. Its contact, located closer to the cable entry point, is common. For a three-pin plug, connect the common pin to the middle pin. Do not connect the connector to any other jacks on your sound card other than the microphone jack.
Step 7
If the capabilities of standard recording programs seem insufficient to you, install Audacity on your computer. If the microphone input of the computer is inoperable, start the mixer program (its name depends on the OS) and enable this input. Adjust its sensitivity.
