AV RF Modulator DIY

Devices with AV output, such as cameras, VCDs, etc., need to be connected to old TVs without AV input terminals. They must use a radio frequency modulator to convert the AV signal into an RF signal before they can be connected to the radio frequency socket of the old TV. If the radio frequency modulator is connected to a radio frequency amplifier and wirelessly transmitted, it can also be used for wireless reception by new and old TVs within a range of more than ten meters.

RF modulators are also DIY for electronic hobbies: common home video game consoles are easy to find at scrap yards, and a RF modulator only costs a few dollars by mail order. The RF modulator in the game console can be turned into a random accessory for cameras, etc. with a slight modification.

The modification method is also very simple: the first step is to accurately find the AV input terminal of the RF modulator. The second step is to cut off the connection (core wire) of the original game console AV output socket. The third step is to connect the AV input terminal of the RF modulator to the original AV socket (output becomes input). The fourth step is to check whether the power supply and other connections are correct according to Figure 1. (Some game console RF modulator power is provided by the motherboard). Everything is in place, and it is done.

RF modulation boxes vary in shape and size, but the circuit principles are basically the same. Figure 1 is provided for analysis reference.

Some early game consoles also have standard conversion circuits. Because the video signals from the mainboards of these game consoles are in N-mode, they must be converted to P-mode before being sent to the RF modulator (the N-mode audio signal can be solved by the adjustable radio frequency modulator core). This is very beneficial for many fans who have N-mode cameras. The N-mode signal of the camera can be connected to the P-mode TV through the radio frequency modulator, and it is no longer a colorless black and white image. Is there a standard conversion circuit on the radio frequency modulator board? Find whether there is a dedicated IC for standard conversion on the board, as shown in Figure 1.

Figure 2 is the measured circuit of the game console's RF amplifier (transmitter). With it used in conjunction with the radio modulator, wireless viewing can be achieved within a range of more than ten meters at home.