Update from April 17: The feed has been running now for a few days non-stop using a really old transceiver (a Kenwood TR-2500 from around 1983). It is pretty useless as a transceiver (dead rechargeable battery, dead memory-retention battery, and no CTCSS), but it’s working well as a scanner. Enjoy the feed.
I’ve been trying to stream audio from a radio over the internet. I started by installing Icecast, a streaming web server (it runs on both Linux and Windows; I installed it on a Linux box). Icecast assumes that another server will send it the audio stream, which Icecast can then send to many clients. There are several servers that can read audio from a soundcard and send it to Icecast, usually as an MP3 or Ogg stream. I tried a few: livecast, ices, and darkice. I could not get any of them to work.
Eventually I found a post in some forum that showed a darkice configuration file which worked for me. I connected to the Linux box from a browser in my Windows laptop and was able to hear the live audio stream. I began to wonder how to make this stream available to others (firewall issues and the like), when I remembered that the forum post that helped me was on RadioReference.com. I decided to check what this web site is.
I discovered that RadioReference.com provides a large number of live radio-channel audio feeds. Many channels cover police, fire departments, and other government agencies (mostly in the US), but there are also quite a few feeds of amateur radio channels, almost all of them VHF and UHF channels. I registered and requested to provide a feed.
A few hours later my request was approved and I was given the technical details of how to connect. The web site suggested that I provide the feed using a Windows application that they provide, but they also have instructions on how to feed the audio using darkice. I configured darkice on the Linux box and started feeding audio. Darkice samples the audio at 8000Hz and send it to RadioReference.com in variable-bit-rate MP3 format (quality setting 0.2) with a high-pass filter at 300Hz and a low-pass at 3500Hz.
The feed is coming now from the FT-857, which is scanning all the local VHF and UHF repeaters as well as some popular Simplex frequencies. The results are excellent. The audio quality through the web is as good as the audio coming out of the radio. I can listen to the feed on a computer or on an iPod (and probably on many other devices).
There are several advantages to this approach relative to using Echolink
- You don’t need the Echolink application, only a browser;
- The stream is available to anybody on the internet, whereas Echolink is only open to licensed radio amateurs;
- By connecting the feed to a scanner you can get a better sense of the activity in an area than with an Echolink node that sits on one frequency.
On the other hand, Echolink allows you to talk to people you hear on the radio, not only to listen to them.
My next step is to try to replace the FT-857 by an old hand-held VHF transceiver and using a dedicated antenna, so the FT-857 and my main antenna are not tied up in this application.