WLOD is back on the air
WLOD is now very different from the analog transmitters used thirty years ago. Now everything is digital up to the FM transmitter. After that it goes out over the air.
The studio and transmitter are at my house. The server is in the cloud hosted on an AWS server running nginx and and icecast2 server. That’s right, there is a server involved. Isn’t there always a server in the loop?
The audio files are MP3 files to save space and reduce latency when using TCP to transfer the audio files to the internet server. I am using ices 0.4 to send the MP3 file steam to the server randomly. Kind of like an automated radio station.
The studio transmitter is hosted on a RPI4 and streams random MP3 files from my song collection to the server in the cloud, stevenlamers.com:8000/stream
http://stevenlamers.com:8000/stream
So far the FM transmitter output is 100 milliwatts. That is not very much power at all, and does not go very far.
On the transmitter side, I am using mplayer to access the cloud server to stream the MP3 file, converting the stream to a WAV file format, that is sent to a named pipe created on the transmitter server.
From there, on the transmitter server, I use a gnuradio python3 script to read from the named pipe and generate the wide band FM signal that is sent via USB to the PLUTO ADALM.
The RF from the pluto is amplified to 100 milliwatts only (of course) and fed to a discone antenna. It does not go very far like I said before. But it sounds awesome over the air. It’s only mono FM though. (sigh)
