8.33 KHz Channel Distribution – What Is This?

Radio Spectrum, a Sparse Resort

One of the simplest actions of a cockpit is radio radio broadcasting to the allocated frequency of whom we want to talk to. Turn the ground control, the tower, or your own company by turning a few buttons until the corresponding numbers appear on the radio control panel display and talk.

Air traffic controllers show the same thing a bit differently. There is usually no tuning of their radio. The appropriate frequencies in the industry or other working environment are defined in advance and do not need any further attention.

Since the case is pedestrian and such acts are so routine, few recognize that each of the pilots and controllers depends on the one of the poorest resources in air travel, namely the radio spectrum intended for use.

Many other disciplines have their own radio spectrum, and we all jealously take care of what they did and for good reason. So many users who want to use radio waves, incumbents are watching or using or losing the principle. Fortunately, the frequencies most commonly used by aviation (118-137 MHz) are not so much wanted by others. Our problem is different, but no less serious.

VHF Fundamentals

VHF is a line-of-site system. This means that two stations can talk to each other assuming they are tuned to the same frequency and see each other (radio viewpoint). If one of the stations is below the horizon of the other station, communication becomes impossible.

Tuning at the same frequency means that both stations are tuned to the same predetermined frequency that is within the flight band. These predetermined frequencies are separated by the "squares" expressed in kHz. The spaces ensure that communication at adjacent predetermined frequencies does not interfere with each other. And here lies the problem!

You can only assign a limited number of frequencies to the required distance if you stay within the flight band. There are several other sectors, towers and other aerospace stations that need their own separate frequency as much as the frequencies are available. So what do we do?

The field of vision of VHF radio waves is a kind of solution. You can use the frequencies again to ensure that each area of ​​use is properly separated so that there is no interference. The frequencies used just near the ground can be used much more easily than used at higher levels. The latter's horizon is much wider, so you can hear hundreds of miles of airplanes in a center that has nothing to do with this if the frequency class is not properly carried out.

I'm not sure who was the first to disturb the radio on an airplane, but the idea quickly and quickly caught the problem of frequency shortage.

Originally, the distance between frequencies was 200 kHz, providing only 70 channels between 118-132 MHz as the band (1947). In 1958, the distance was reduced to 100 kHz, doubling the number of channels to 140. In 1959, the upper limit of the aviation band was extended to 136 MHz, giving another 180 channels to the 180. [19659003] In 1964, the channel distance was reduced to 50 kHz, so there are 360 ​​channels available

These dates show not only the famine of increasing flying frequencies but also the development of aviation radios. In the 1950s, no radio set would be suitable for machining the 50 kHz distance. By 1964 the 50 kHz was the basic requirement, hereinafter …

The channel distance was further cut to 25 kHz in 1972 and doubled the available channels to 720. Seven years later, in 1979, the band's upper limit was expanded, this time to 137MHz, and it provided another 40 channels, bringing the total to 760. [1995] In 1995, the proposal was requested to reduce the channel spacing to 8.33 kHz. The theoretical number of channels is 2280!

This sounds like the nirvana radio channel, but in real life things are never that simple.

Causes of Canal Hunger

driven mainly by a dramatic increase in the number of control sectors in the ATC context of traffic management. With increasing traffic, air traffic service providers had to divide sectors into smaller pieces to allow inspectors to cope. Each new sector had its own frequency, and most of the sectors were in the upper airspace, so the reuse distance between the same frequencies was very high. It turned out to be an seemingly insatiable hunger that went through more and more discrete frequencies

By the mid-nineties, it became clear that the existing VHF system could not reach the required frequency. This would put an end to the creation of new sectors that severely restricted the ability of the ATC system to tackle rising aviation needs.

Interestingly, the magnitude of the problem was not consistent with the United States and the United States in Europe

Although US bandwidths were much higher than the busiest areas in Europe, US frequency hosts did not have the FAA to meet the demand for new frequencies. At the same time, in Europe, with lower traffic density, the alarm bells sounded that the end of the world's frequency was close.

So what happened?

To understand this, it's important to note that frequency guides European states were part of the communication side of things, often linked to old postal monopolies and did not actually get international cooperation or concerns about aviation problems outside their own country. This aviation was no longer a purely domestic relationship, apparently it did not really affect them.

Although states have never officially acknowledged this, most of the frequency shortage was due to the poor handling of available frequencies. Valuable frequencies went to sleep, never used or simply left in the powder after the body was originally used for a long time gone.

Airspace users have raised the issue, have brought many examples, but in vain. The local music of the frequency management did not emerge, so there was no choice but to study the technological solutions

Choosing the 8,33 kHz channel selection and VDL mode 3

the ambition to resolve the frequency shortage fear of climatic delays, experts have said since the 1980s that the entire aeronautical communication system is needed for refurbishment. The newly identified VHF AM sound system and the freshly identified future air / ground digital connections require a common solution to address frequency shortages and future communication needs

Keep in mind that huge progress has been made in other areas of communication at the same time, while air transport still sought to think about replacing a less-than-changed voice communication system since the 1940s and which clearly fought to maintain demand

In the United States, a VDL Mode 3 system was proposed. This system would allow four digital channels to be used on all existing 25 kHz channels and provide non-voice-based data transfer capability. In addition to the United States, many believers were not in the feasibility of such a technique and still have not been implemented anywhere.

In Europe, allocating the channel distance to 8.33 kHz is the best solution. Missing a once-lifetime opportunity, the industry did not look into long-term alternatives …

Decision 8.33 and follow-ups

As mentioned above, airspace users have not been convinced of any change of currency when it comes to modifying aircraft when it thinks the frequency shortage was primarily due to the poor handling of the aviation spectrum

In this ambivalent mood, the sector gathered at the ICAO European Regional Aviation Meeting (EUR RAN) in 1994, where proposals for managing frequency shortage they had to argue and make decisions.

For the current generation of ATM decision makers, it is worth mentioning that most decisions were made. To solve the frequency shortage, 8.33 kHz was detected without ever considering possible alternatives and without examining cost-benefit considerations, user effects, or longer-term communication requirements. Obviously, it's not something that must be brought back … ever.

Airspace users, with more severe delays and misleading protests on their heads, had no other choice than the mandate: 8.33 kHz of European airspace since 1 January 1998.

ICAO's European Air Navigation Design Group (EANPG) has commissioned the introduction of a new channel allocation. However, EANPG asked EUROCONTROL to develop and implement a transitional plan.

This is a very important detail to remember. Until now, airspace users blame EUROCONTROL for the whole number 8.33, in fact, EUROCONTROL is only an agent appointed by ICAO (states with whom you say it) to implement. They have done a great job and not EUROCONTROL's failure to guide them to achieve a less optimal solution. If we think that EUROCONTROL had to deal with all the European ICAO member states (49) and have had to create a mixed 25 kHz / 8.33 kHz environment, the ultimate achievement of the targets is even more recognizable.

Mr. Murphy and the Implementation Plan 8,33

"If that can be done, then," says Murphy's first law, and this is certainly true of this implementation.

EUROCONTROL has rightly decided to deal with the case and they have been well-received for the involvement of IFATCA and IATA organizations such as IFATCA and IATA organizations to provide direct contacts with end-users of the new system .

against a time problem. The first steps were taken only at the beginning of 1996, and the deadline of 1 January 1998 was a clear questionnaire. Thus, the first delay reduced the deadline on 1 January 1999 and the second delay until 7 October 1999.

Why is Delay Delayed? The gear speed was the primary and determining factor.

A number of entrenched aircraft equipment scenarios show a slow mounting mounting curve at the beginning, as only a few aircraft are fitted, and with the deadline approaching, the curve is very steep but usually does not reach 100% before the mandate. What it means?

Clearly, airspace users do not want to spend money too early and fly with new equipment without any benefit. When the time comes and equipment is inevitable, there is a crazy rush, which, however, may be missing in the equipment and overload the reinstallation stores. Finally, there are inevitably airplanes in the cold because they can not fulfill the order.

All this happened at 8.33, and then more.

At the start of the project, there are no 8.33 kHz radios on the market. Some pre-production samples were made, but nobody could buy it. Despite the clear mandate, the presence of the competing VDL Mode 3 system and the fact that 8.33 is only required in Europe led some manufacturers to slow down product development and did not create anything until customers had firm orders. Clients, however, refuse to make orders closer to the deadline for the order due to the lack of radio equipment due to a low installation rate! It's a vicious circle if you've ever been … Sometimes at the meeting of the 8.33 project team, most participants were enthusiastic about the whole thing to go …

Then there were the planes. No matter how advanced the new radios are 8.33 kHz, very little distance between the channels and the tests on different aircraft revealed the surprising behavior. The Boeing 767 radios, for example, worked as long as the doors were open, but started to bother when they were locked …

The controllers were worried about what would happen if pilots regularly lost the radio. True, for the first time, the numbers on the radio control panel do not show the actual frequency of the 8,33-channel channels and this could be confusing.

Issues related to new cellular phone terms have also been put on the agenda.

Finally, however, the final deadline came and went, and the new system worked well. In addition to some isolated events, no problems were reported, and 8.33 kHz, like any other part of the ATM system, became part of the European scene.

Next Steps

In the meantime, EUROCONTROL continued to handle the 8.33 kHz execution and extend its use to the lower airspace. They have fulfilled and continue to fulfill the role assigned to them by EANPG, and the specific benefits of 8.33 kHz will certainly continue to accumulate. It also sounds like the FAA also wants to watch the 8.33kHz channel distance for US launch.

Has the benefits been realized?

This all depends on how you want to measure the benefits. If the measure is the number of requests for new frequencies that can be accepted, the result of the exercise is definitely positive. After the introduction of the 8.33kHz channel layout, 57 of the 59 requests were first assigned to the first frequency plan design meeting, the absolute first. The level of satisfaction of the subsequent request is similar.

It is very likely that a comparison with a "nothing" scenario shows that the 8.33 kHz investment is not a bad idea.

On the other hand, 8.33 A kHz gave the impression that the problem was solved and the motivation to really address the shortcomings of the obsolete communication system has disappeared. When deciding on a 8.33 kHz decision, it would have been easier to initiate the development of a new system that now provides pilots with the same level of passenger service in the near future.

For example, it has a legacy system that is much more difficult to switch to industry, not least because of the miserable airlines these days.

It is a pity that the EUR RAN meeting in 1994 did not have the vision to look at the immediate solution to the problem of frequency shortage.

Source by sbobet

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