N766AS From , joined Dec 1969, posts, RR:
Reply 1, posted (14 years 11 months 2 weeks 6 days 8 hours ago) and read 4614 times:
The airport uses a piece of hardware (about a cubic foot in size) called a receiver/decoder/controller. It receives the signal from the aircraft, then decodes it into the number of short bursts, then controlls the lights based on how many bursts it received. This equipment costs about US$1500.
David L From United Kingdom, joined May 1999, 9628 posts, RR: 42
Reply 4, posted (14 years 11 months 2 weeks 3 days 10 hours ago) and read 4541 times:
Thanks, Neil. But what aspects of the lighting are controlled? Is it just used to turn the lights on/up when an aircraft needs them or can the pilots choose which lights they want to see and alter the brightness to their own needs?
CP744 From Canada, joined Jul 2000, 200 posts, RR: 0
Reply 5, posted (14 years 11 months 2 weeks 3 days 9 hours ago) and read 4541 times:
It controls the approach, runway and taxiway ( if applicable ) lighting and on some systems it does control the intensity by the number of times you key the microphone. It does not allow you to select which lights you see, it turns all aids on.... and you can sometimes turn them on for varying lengths of time based on how may times the mic is keyed.
Aaron atp From United States of America, joined Mar 2000, 533 posts, RR: 2
Reply 8, posted (14 years 11 months 2 weeks 2 days 17 hours ago) and read 4516 times:
>>>Since aviation radios are full duplex, how can it distinguish between mic clicks and voice at the same time?
Aviation radios are a simplex type. They send and receive on the same frequency -and can only do one at a time. FYI, marine comm radios have duplex channels (20, 24-28, & 84-88) for communicating with land lines via a marine operator. Pilots do not have such a luxury.
Distinguishing mike clicks is actually quite easy. AvCom radios use something called double-sideband suppressed-carrier amplitude modulation to transmit voice. The receiving radio suppresses the carrier wave and only amps the voice wave, which is demodulated from the carrier. The PCL controller needs only to listen for pulses of the carrier wave on the CTAF frequency. This makes it a much simpler device than the radio in your aircraft. It doesn't even need to demodulate the signal to separate the voice transmission.