Audio Watchdog

 

In order to be on-air, radio stations that operate from multiple transmitter sites must develop effective and efficient means to distribute their studio output.

Many radio stations rely on satellite transmission for their Studio Transmitter Link (STL) connection. In other cases, transmitter sites pick up their primary audio source from cable connections or even FM transmission from a neighboring site (i.e. ball reception).

In many cases satellite transmission is the most efficient method, especially when you have multiple transmission sites. Any transmitter site is capable of picking up the audio source with the use of an ordinary satellite dish. However, as proven by fact, satellite also has its drawbacks: either weather conditions (such as snow or heavy rain) may impair clear and uninterrupted transmission or reception, or the satellite itself spins out of orbit.

Regardless of the transmission method, the show must go own, no matter what. Listeners expect their favorite radio station to be on-air 24/7, while advertisers want their money’s worth. In short, a (temporary) black-out is a burden to any radio network executive.

Hence, it is always wise to have a back-up available when the primary audio source fails. The most reliable secondary sources include ISDN codecs or direct radio-beam links. For cost-benefit reasons, most stations choose ISDN.

The Audio Watchdog from Broadcast Partners is a combined solution of hardware and software which serves as an active backup connection when the primary audio feed fails:

  • Hardware
    The VTR424 connects the primary/secundary audio source to a regular on-air tuner, which checks the on-air signal. If the audio degrades or fails it switches automatically to the backup connection (e.g. ISDN). This device also allows for manual switching.
  • Software
    The Audio Watchdog software module can be installed on any PC and connects with the VTR424 via a dial-up modem or full-duplex ISDN-codec.

Configurations

Because the distributed signal is supplied digitally, it is wise (if not essential) to use an ISDN codec in the studio identical to the codec on the transmitter side of the link.

There are two different types of configurations:

  • Weather Back-Up
    Because none of the weather conditions on the sites are exactly identical (if there's a thunderstorm in Hilversum, the sun might shine in Eindhoven), 1 or 2 codecs for each 10 transmitter sites are used.
  • Full Back-up
    Stations that use a single signal divider for each 15 sites, or use a full redundancy solution, where each site has its own codec (including a separate codec in the studio).

Applications

Most configurations have their primary audio source connected to a satellite receiver, and the secondary source to an ISDN codec. The third VTR424 input is connected an on-air tuner located on the transmitter site. This has the advantages of:

  • Automatic back-up switch
    The BP Audio watchdog can switch one or two alternative audio sources when the primary audio quality degrades, by using the watchdog's internal detection.

  • Remote STL control
    The BP Audio Watchdog can, besides crisis management, inspect the primary audio source from any location that has an ISDN codec.

  • Remote Air-check 
    The ISDN codec can listen to the on-air signal from the site's tuner.

  • Site Console integration
    The Audio Watchdog is separately available, but also as an integrated part of Site, the remote radio network management solution by Broadcast Partners.