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Experiments with UHF transmitter modules UHF transmitter and receiver modules are used for a wide range of short range applications such as remote control or slow speed data transmission. A common frequency used is around 433.9 MHz, which puts it inside the amateur 70cm amateur band. While their use can interfere with amateur activity in our case having these modules operate within our band means that amateurs have a head start when it comes to equipment and antennas to experiment with them. The modules I had were marketed as data modules. My early experiments were to get them to transmit sounds and then AM or FM voice. This was successful but I found that some settings, such as the bias voltage on the module's data input connection, greatly affected transmission frequency and modulation quality. The transmitter modules are designed for use with superregenerative receiver modules. Both have very short antennas designed for limited range. But if you were to use amateur gear with good antennas then the modules can transmit surprisingly far. Especially if you're able to put them on a frequency less prone to interference from other low power devices. Watch the videos below for further details, including circuit diagrams and range tests. Demonstrations of UHF transmitter modules Introduction   Attempts at transmitting voice   Adding a 555 audio oscillator   Clearer AM and FM voice transmissions   Even better AM and FM voice transmission   Another range test with UHF modules   Adding an electret microphone to UHF transmitter modules   AM voice transmissions to companion UHF receiver module   Using a flashing LED to give distinctive keying   Possible useful items for UHF module experiments   Disclosure: I receive a small commission from items purchased through links on this site. Items were chosen for likely usefulness and a satisfaction rating of 4/5 or better.

Books by VK3YE Ham Radio Get Started (USA) Australian Ham Radio Handbook (Aust) Hand-carried QRP Antennas More Hand-carried QRP Antennas 99 things you can do with Amateur Radio Getting back into Amateur Radio Minimum QRP Illustrated International Ham Radio Dictionary Make your Passion Pay (ebook writing)   All material on this site (c) Peter Parker VK3YE 1997 - 2024. Material may not be reproduced without permission. Read privacy policy.