Lump Jockey
1st Feb 2003, 11:07
Hello! Being nothing but an enthusiast, I was wondering after looking at one of my charts, at the LAM VOR arond London, why does it say Ch 103 (DME) next to it? How do you tune a channel in, if at all poss? And what is it exactly? :O
I'm sure someone will jump in and tell me if I'm wrong, but in teh case of a VOR/DME navaid, each VOR freq (ie. 110.30MHz, which is VHF), is associated with a DME frequency, which is UHF, and usually expressed as a 'channel' number. On the flight deck the crew only has to dial in the VHF frequency of the VOR, 110.3, and the black box in the a/c knows this is always paired with UHF channel 103 (say), and tunes that in automatically.
DME - Distance measuring equipment. Tells you how far from the VOR you are. Only gives slant range though, so even though you may be flying directly overhead it at 30000 feet or so, it will still read as 6 miles away (directly beneath you).
Gonzo.
Flybywyre
1st Feb 2003, 12:05
Channel's used to be use in conjunction with TACAN (TACtical Air Navigation (TACAN) ) and I believe were mainly used by the military. There used to be 126 channels each of which corresponded to a VHF frequency. If you look in the yellow Aerad supplement you will see a conversion table that tells you what frequency you need to correspond with the relevant channel. These channels will operate your DME.
All from memory so I stand by to be corrected.