Online flying network VATSIM is set to launch a brand new voice communications system on Monday 14th October.
Audio for VATSIM (AFV) brings not just a new Opus-based codec, but also a full VHF and HF voice simulation complete with optional highly realistic VHF and HF distortion, range degradation and much more.
The system includes a worlwide database of ATC transceivers and a reduction in latency of up to 80% compared with the current system, reducing the likelihood of crossed transmissions.
The heart of AFV is a highly realistic VHF and HF radio simulation, with voice processing effects verified by real-world professional pilots and air traffic controllers. The concept of 'voice rooms' hosted by a controller is removed, meaning pilots can transmit voice on any frequency at any time. Range effects and degradation are simulated, with aircraft radio range primarily dependent upon altitude.
The further the receiver is from a transmission's source, the more crackly and degraded the signal becomes. It is possible that in some areas pilots may find themselves in realistic radio 'dead zones' where they are unable to make voice contact with a controller, just like in real life.
Voice UNICOM -- artificially range limited to reduce the number of non-pertinent transmissions received -- will be available from launch. It is anticipated that voice CTAF on discrete frequencies will eventually replace the single-frequency UNICOM system once further work has been completed to support this transition.
Oceanic and remote continental communications are also revolutionised through the ground-breaking High Frequency (HF) radio simulation. For ATC stations defined with frequencies in the HF band, AFV provides a unique 'frequency alias' system -- pilots tune their VHF radio to the station's designated 'alias' frequency and the AFV system automatically internally converts this to the HF band, allowing all users to access these services. After release, an SDK will also be made available for aircraft developers who wish to enable direct HF tuning via their own in-cockpit HF radio gauges.
The system also incorporates realistic half-duplex operation -- when a pilot or controller transmits, they will be unable to hear any other transmissions on their frequency until they release their PTT switch. When two or more stations transmit simultaneously, other users will hear a realistic heterodyne tone and a garbled mix of both transmissions.
Audio for VATSIM is a totally free upgrade for all VATSIM members, who will be required to perform a small update to their pilot or controller clients to support the upgrade. More information can be found at the official AFV website https://audio.vatsim.net/.