In the past I've covered some of the ins and outs of syndication. In the early days it relied upon the US Postal service circulating pre-recorded programs. The formats varied over time starting with transcription discs eventually moving to LPs and reels. Today a few programs still circulate on CD-Rs. I have no idea why.
National Public Radio was the trail blazer here as it often is. In 1979 public radio took syndication into the space age. Their Galaxy IV satellite was launched by PanAmSat Corp. All Public Radio affiliates are now interconnected by satellite. That satellite made it possible to distribute both live and pre-recorded programs simultaneously to all their affiliates. The reels of the past were buried in the yard and AMPEX suffered a drop in the value of their stock. More here.
Today that tin can inthe sky has grown into PRSS (The Public Radio Satellite System.) it's a full-fledged distribution network. Thousands of hours of programming are distributed to hundreds of public radio stations across America. The interconnected stations own their own downlink and uplink equipment but the NOC that manages the network is located in Washington D.C. at NPR headquarters on 635 Massachusetts Ave., NW, Washington, DC
The satellite system uses a digital transmission format called MUSICAM. It's a specialized perceptual coding algorithm for data compression. NPR has very high standards for audio quality and standard audio compression is totally unacceptable to them. They output the signal in three formats. More here.
1. Compressed Digital
2. Linear Digital
3. Standard Analog
The hardware is very pricey at every step of the system but it's better faster and more reliable than parcel post. But the system like any other satellite is susceptible to solar interference. This is predictable much like the rising of the sun itself and can be avoided through a little planning. But on May 19th 1998 the satellite went for a little joyride. The Galaxy IV just stopped working and began to spin. The feed of feeds of All Things Considered ceased. NPR switched over to telephone relays to distribute programming over the course of the next day.Interestingly the satellite was also used for paging srvices so hundreds of pagers died as well.
Some stations froze and had several minutes of dad air. feeds of All Things Considered. 90.9 WBUR, Boston, bragged that it suffered only five seconds of dead air before switching to another program. While PanAmSat had insured the Galaxy IV for about $150 million that's nothing in the face of the replacement cost. At the time of the failure they estimated that cost at about $250 million.