Joined: 11 Dec 2005
|Posted: Sat Mar 30, 2013 11:28 am Post subject: Frequency Spacing and Reporting
As technology has developed, the spacing between allocated VHF frequencies has been progressively reduced from 50 KHz to 25 KHz and now to 8.33KHz
8.33 KHz spacing is mandatory on all aircraft operating above FL 195 in the European region.
Because modern radio equipment only displays frequencies to three decimal places the frequency displayed on the comms controller is rarely the exact frequency that is being used.
e.g. an actual frequency of 132.00833 MHz would be selected and referred to as 132.010.
Reporting VHF Frequencies
When reporting VHF frequencies, if the frequency ends in two zeros you can leave them out.
e.g. frequency 132.500 is transmitted as: ONE THREE TWO DECIMAL FIVE
In other cases you must use all six digits, frequency 132.020 would be transmitted as ONE THREE TWO DECIMAL ZERO TWO ZERO
If ATC wish to determine whether or not an aircraft has radios with an 8.33 KHz capability they will ask.
The response is either:
AFFIRM EIGHT POINT THREE THREE or NEGATIVE EIGHT POINT THREE THREE
Note the use of "POINT" rather than the usual "DECIMAL".