Primarily for general aviation discussion, but other aviation topics are also welcome.
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By UpThere
#1566333
riverrock wrote:The hope was that just changing the upper airways to 8.33 would be enough, and they would be able to scrap the plan for changing lower frequencies, but there is still frequency congestion so the plan has had to keep moving.

Is that to fulfil the demands of all the new airports which have been opening?
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By G-JWTP
FLYER Club Member  FLYER Club Member
#1566365
Marvin wrote:
Robin500 wrote:That is all well and good, except frequency congestion is in large a myth.


Based on what evidence?


There was a German chap, something to do with AOPA, cannot remember his name but a statistician who came up with the fact that there is no frequency congestion if the allocation was done by central agency as opposed to , by Country, as is now.

The Boss man may know his name.

G-JWTP
#1566382
G-JWTP wrote:There was a German chap, something to do with AOPA, cannot remember his name but a statistician who came up with the fact that there is no frequency congestion if the allocation was done by central agency as opposed to , by Country, as is now.

This is broadly correct. The European model for frequency allocations is rather inefficient, especially for the smaller countries with numerous borders. The UK has always had an efficient frequency allocation system (yes, really!) and has no need of 8.33, certainly not below FL195. Partly we benefit from being an island, of course.

Instead of looking to ways to improve the efficiency, the decision was taken to force every aircraft and every ground station to buy new 8.33kHz kit. Nowhere else in the world has found the need to do this and the cost is astronomical.

I may be out of date but as far as I know, the only 8.33kHz allocations that have been made by the CAA (i.e. not on a 25kHz boundary) are above FL195 and "company" frequencies that GA would never have any reason to talk to. This approach is consistent with the fact that we are not really short of frequencies here in the UK.
#1566439
Ha! tWF's carpentry skills are still up to scratch then! :cheers:

Something to do with all those years working in air traffic engineering :study:, dealing with the CAA :wall:, flying light aircraft 8) and generally mucking about with wirelessry :scratch:, I guess.
By GAFlyer4Fun
#1566448
Robin500 wrote:That is all well and good, except frequency congestion is in large a myth.


Is that the same flavour of congestion that says all of our skies (inc class G) are so congested that we all need to go out and buy electronic conspicuity/traffic alerting devices (as Mode S/C is not enough for our puddle jumpers) due to there being so much traffic we might miss one that we then bump into.
I always challenge my passengers to spot another aircraft and to tell me/point it out just in case they see it before I do so that I can do whatever needs to be done to avoid collision. Most of the time they don't spot one outside the circuit. :wink:
<end of thread drift>
#1566460
CloudHound wrote:Ah, but can you catch a Wiggley Amp?

Well perhaps not the real WigglyAmp, he can run faster than me. But yer every day wiggly things? Been doin' it for years and have the RF burns to prove it!

Little wiggles are the secret of radio. You take wiggly amps and wiggly volts and bang them together inside the radio to produce wiggly watts which then escape up the coaxial cable to the antenna. With nowhere else to go they leap off into the air and become little wiggles. A few of those little wiggles are lucky and find their way to the antenna on the control tower roof. So delighted are they to be back in a radio again that they insist on telling their story in the controller's headset. And that, boys and girls, is how radio works.
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By chevvron
#1566464
Robin500 wrote:That is all well and good, except frequency congestion is in large a myth.

True.
The USA manages without using 8.33 spacing, why can't we?
By chevvron
#1566467
The Westmorland Flyer wrote:I may be out of date but as far as I know, the only 8.33kHz allocations that have been made by the CAA (i.e. not on a 25kHz boundary) are above FL195 and "company" frequencies that GA would never have any reason to talk to. This approach is consistent with the fact that we are not really short of frequencies here in the UK.

That was the official CAA policy in the days when I used to attend UK Phraseology Working Group meetings.
I can only think the extra demand by the RAF for VHF freqencies has messed it up where they used to use almost exclusively UHF band frequencies with just one or two VHF for backup, (usually NATO 'common' frequencies like 122.1 and 123.3), nowadays some airfields have a VHF frequency allocated for every possible control position.
Look at the AIP listing for Northolt if you don't believe me; no less than 8 VHF frequencies for 6 control positions plus Ops and ATIS where a busier civil airfield only uses 3 or 4. How often do Northolt 'need' to use all these frequencies at once, indeed do they have the staff (at Swanwick) to 'man' them?(Obviously, Tower and GMC are done from Northolt; not sure about Talkdown, but the others, approach, director and departures are done from Swanwick)
Benson and Odiham airfields are others which have acquired 'extra' (and probably rarely used) VHF frequencies over the years.
By riverrock
FLYER Club Member  FLYER Club Member
#1566476
chevvron wrote:
Robin500 wrote:That is all well and good, except frequency congestion is in large a myth.

True.
The USA manages without using 8.33 spacing, why can't we?

Because we have a higher density of airfields.
By riverrock
FLYER Club Member  FLYER Club Member
#1566477
The Westmorland Flyer wrote:
G-JWTP wrote:There was a German chap, something to do with AOPA, cannot remember his name but a statistician who came up with the fact that there is no frequency congestion if the allocation was done by central agency as opposed to , by Country, as is now.

This is broadly correct. The European model for frequency allocations is rather inefficient, especially for the smaller countries with numerous borders. The UK has always had an efficient frequency allocation system (yes, really!) and has no need of 8.33, certainly not below FL195. Partly we benefit from being an island, of course.

Eurocontrol act as the European Network Manager - coordinating allocation of frequencies. In some areas, the request for a single frequency by a traffic provider can take a year and involve shifting 6 other frequencies. 43% of new frequency requests are abandoned.
https://www.eurocontrol.int/sites/defau ... tsheet.pdf
By chevvron
#1566478
Paul_Sengupta wrote:How many RAF stations have closed in the past couple of decades? How many frequencies has this freed up?

Very few because, as I said, many operated on 'NATO standard' frequencies and as the other frequencies are allocated to MOD(Air) they're held 'in reserve' for future use (provided they meet ITU criteria for DOC). Has Lyneham Radar 123.4 been re-allocated for instance?
Remember about 10 years ago when the Brize Radar frequency suddenly changed from 134.3 to 124.275? That was because 134.3 was allocated to MOD (Air) as an Area Radar frequency but not specifically to Brize, so when they wanted to allocate it to Swanwick Mil, they found to get a decent DOC for that unit, they had to allocate a different frequency to Brize. In fact I did hear that it shouldn't have been allocated to Brize in the first place, but way back in the '70s when they were about to open 'Cotswold Radar' (which was an Area Radar unit as well as LARS) at Brize, they needed a frequency in a hurry and found that MOD 'owned' 134.3 so without checking the DOC, it was given to Brize.
How true that is I don't know.
Also don't forget, Safetycom (135.475) , which many people in the LAA (then called PFA) and other organisations fought hard to get, was allocated for use in the vicinity of airfields which had no frequency allocated to them, but the RAF decided to use it as a 'general broadcast' frequency in the Scottish Highlands, a purpose for which it was never intended.
Last edited by chevvron on Fri Oct 20, 2017 12:31 pm, edited 3 times in total.
By scottish_ppl
#1566523
Whoever is allegedly using the frequencies, there is no justifiable reason to force private aircraft into upgrading. The existing transmitters do not interfere with new channels, and people could decide for themselves in due time if the frequencies they could not receive meant the cost/benefit was in favour of upgrading.
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