I don´t believe that the range of the typical aircraft radio is that large so you could communicate from Madrid to Paris
Madrid to Paris is 568 nautical miles. That’s not far off the line of sight distance between two aircraft at FL660 (the top of controlled airspace in most places). Sounds to me like that’s almost exactly the distance you would need between enroute sectors, without any buffer for ducting etc…
Madrid to Paris is 568 nautical miles. That’s not far off the line of sight distance between two aircraft at FL660 (the top of controlled airspace in most places). Sounds to me like that’s almost exactly the distance you would need between enroute sectors, without any buffer for ducting etc…
I don’t think one would allocate every frequency with such a buffer.
For example the Shoreham approach/tower frequency of 123.15 can be safely duplicated say 100nm away (because it will never be used by FL600, or even FL300, traffic) and actually I think it has been duplicated fairly near. Certainly their DME frequency is re-used somewhere in N France. Same for Farnborough 125.25 (Bergerac?).
Upper airspace frequencies would need a big buffer, but there aren’t so many of them.
Also VHF won’t work over 586nm because notwithstanding the theoretical line of sight allowing that, the attenuation will take it below the squelch of a standard VHF radio. Otherwise, you could use your 10W radio all the way to the moon. (Actually they did exactly that in those days but they had a parabolic antenna at the moon end, and something parabolic and massive at the earth end).
One factor that I can think of that might allow the US to be comfortable with less frequencies is that most airports (numerically speaking) share a handful of CTAF (common traffic advisory) frequencies. On these frequencies you can hear distant airports assigned the same channel. But I’d agree that 100 nm or so ought to be enough spacing for most frequencies that need to be dedicated to a certain controller and his airspace.
Given the low altitude VHF range limitation I can’t imagine how 2280 aircraft communication frequencies is necessary unless you are trying to set up a low probability of any sector or airport randomly & independently picking the same frequency, regardless of the geographic potential for interference, which means having a lot of channels and leaving most of them empty. That train of thought would neglect that in making their choice they could consider what others within 100 nm (or whatever applies to the particular airspace and altitude) are already using.
For example the Shoreham approach/tower frequency of 123.15 can be safely duplicated say 100nm away
Some smaller aerodromes and most (if not all) ultralight strips in Czech Republic are on several shared frequencies. When flying in the vicinity of one at a typical bimbling altitude, one can occasionally hear another station some 50 NM away, but never at the other end of the country (which is some 270 NM in the longest dimension)
Well, yes, something else which can never work in Europe (because it works in the USA and we all know they have a different oxygen % in the lower atmosphere there) is calling up with
“N123XY final runway 06 < airport name >”
The huge problem with that is that one would need to train pilots to use the radio, which can’t be done because that’s what they do in the USA and it can’t work here because …. 
They do it in France, though, where the vast majority of fields use one and the same frq – 123,500 if memory serves. Every call there actually begins with the a/d name. And like many things in France, it may look weird to a foreigner but it works very well.
BTW out of curiosity I searched my own records, and found the somewhat exotic frequency of 118,925 MHz in use at no less than 9 fields across Europe – one each in Belgium and Hungary, five in Germany, and two in UK: Lee-on-Solent and Llanbedr, not so very distant. Can’t take any oath to that info being up to date, though. It certain can’t claim to be complete.
They do it in France, though, where the vast majority of fields use one and the same frq – 123,500 if memory serves. Every call there actually begins with the a/d name.
Same thing in Sweden. You are technically calling the ground station, so the message always begins with the ground station callsign.
The VCS II final report (2 MB zip file) has the “Justification Material”. I’m not defending it, I’m just pointing out where you can find it!
Page 66 makes interesting reading.
Total estimated cost of equipment for civil aircraft – 217 million Euro
Paid by those benefitting (CAT) – 14 million Euro (6.5%)
Paid by others (IFR < 2t, helicopters, VFR traffic) – 203 million Euro (93.5%)
This compares to a benefit of around 600 million euros in avoided delays, primarily accruing to CAT.
