Modifying an AliExpress AM Transmitter

Adding some much-needed cool running, frequency stability and audio processing to the AliExpress Experimental AM transmitter #retroelectronics #arduino #radio #transmitter #retrotech #vintageelectronics #vintageradio Nano code can be found here: https://github.com/andydoswell/MW-Nano Teensy code can be found here: https://github.com/andydoswell/Teensy-MW Chart for looking up the channels can be found here: https://docs.google.com/spreadsheets/d/e/2PACX-1vQrt4R98PXVgvQs7_eSd4-cQbX29Ex-cV4kbz5AbT8VLDS7yDVSDJ-Q7L2dhGqsLM8YITJv1XtkbZ4K/pubhtml There's also a write up on my blog https://andydoz.blogspot.com/2025/01/improving-aliexpress-am-tramnsmitter.html Buy me a coffee if you'd like https://ko-fi.com/doztelevision Pop into to Dozcord for a chat https://discord.com/invite/k77BJrsXx2 0:00 Intro 0:44 Looking at the instructions 2:18 Walking through the schematic 7:28 The issues 7:45 Fixing the modulator 10:21 Precautions for use, and legality 13:02 Frequency stability 14:36 Enter the AD9833 15:44 Testing the oscillator 17:44 Checking the amplitude of the original oscillator 19:35 Winging it... 21:29 Testing & audio processing thoughts 24:33 Audio processing in DSP 27:04 Testing the audio processing 27:40 Looking at the code 31:21 Trying out the filter/compressor 35:06 Trying the earlier version 40:30 Trying spoken word 41:32 Adding frequency agility 52:51 Calibrating the frequency 47:12 Integrating the audio processing and oscillator 47:53 Outro