Streaming Radio – Doing it right

This is something that has come up time and time again now, and with Amazing Radio going online-only with nothing but a single Shoutcast server streaming one format at one bitrate, now seemed like a good time to write about online streaming of radio stations.

Let’s start by briefly looking at real broadcast operations – on FM and AM we try and maximise coverage (within our license), maximise compatibility, and of course we want to add as much value as we can with metadata like RDS (and now things like RadioDNS). We’re trying to reach as many people as possible, with as little fuss as possible, and trying to give people the best possible service.

This is not what many broadcasters do with their online offerings, which is a real shame, considering the potential that many stations have. So what constitutes a best-effort service? What makes life easier for listeners, and how can you make your station’s output as widely available as possible? I’m just going to skim over the technology here and break things down. I’m also going to discuss briefly what we’ve done with the streams at Insanity Radio 103.2 FM, and how we’ve worked them into apps and our new Radioplayer implementation. Continue reading Streaming Radio – Doing it right

Engineering FM – Part 4

Time for the exciting fourth instalment of my ongoing series on engineering at a small community radio station launching an FM service for the first time. In this post I’m going to be looking (somewhat briefly) at processing.

There’s been a place for processors ever since radio has existed, to make sure that audio input to a modulator doesn’t exceed the modulator’s input limits without making the audio itself sound bad. This typically involved an automatic gain control circuit, or AGC. As time went by, these evolved into multiband AGCs, processing in typically four chunks for LF, LMF, HMF, and HF audio segments. Clippers and limiters were also used to protect equipment but as stations aimed for a competitive edge processors became used to make stations sound louder and punchier by maximising the amount of modulation used at any time. Continue reading Engineering FM – Part 4