BackPacker wrote:
Can they do the same thing within the bandwidth of an 8.33 channel?
I wrote about that in the post that was moved back into the original thread. It’s the one below this: http://www.euroga.org/forums/hangar-talk/6491-threatened-7500-fine-over-8-33-capability/post/117885#117885
[I have moved it back here – Peter]
BackPacker, the human hearing range is much wider, typically 20 Hz to 20 kHz for young people, with the upper boundary decreasing with age. 3-4 kHz is the upper boundary of the frequency band for speech – or, more precisely, you won’t lose intelligibility if you cut off the overtones above that. To remove 1.67 kHz, you will need a highly selective notch filter, and even that is likely to affect intelligibility.
So, in short, no?
I wonder how Dutch Mil INFO (now 132.350, to become 132.355 later on) is going to handle this. They’ve got a bunch of transmitters as well, to provide low-level coverage across the country. Although I believe they use a slightly different system. As per the AIP we’re always asked to report our approximate position on first contact, so that they can use the transmitter that’s closest to us.
same issue in the London FIR for the 2 info frequencies. Not sure in Scotland.
I see several option:
Build a very tall antenna and very powerfull transmitter = lots of money
Split in several sectors, more ATCO/FISO = money
Stay on a 25kHz channel. Possible due to the tricks discussed. loose 2 8.33 channels. Not much money
BackPacker wrote:
So, in short, no?
If anyone is looking for the post, it’s now below http://www.euroga.org/forums/maintenance-avionics/1808-8-33-interference-on-25khz-radios-true-or-false-merged/post/117966#117966 . In short, only two-legged climax is possible on a channel with 8.33 spacing utilizing ±2.5 kHz offset. In other words, you either have one leg with f+0 or two legs with f-2.5 and f+2.5. E.g. redundancy in a terminal area is achievable with 8.33 (that is if you’re satisfied with dual and don’t need triple or more). The regulation about conversion to 8.33 doesn’t apply to channels utilizing offset carriers so they can keep them on 25 kHz if they want to.
