8.33kHz radios, where are they already in use, UK?

[rans6andrew]

so now that we have all been out and bought nice shiny new radios, with 8.33kHz capability (we have, haven't we?) in order to comply with the requirements soon to be in place, where can go where they are already in use?

There must be somewhere? Surely?

[TCAS FAN]

West Wales Radar 127.090 MHZ. They manage Danger Areas in the D201 & D202 block for flying UAVs from West Wales Aberporth when NATS Aberporth not doing so. Was talking to them recently, nice bunch of guys, very helpful, got a direct route through the Danger Areas with a de-confliction service.

[dont overfil]

Cumbernauld Radio 120.605

[BossEyed]

Is a DACS For the Aberporth Danger Areas and access to Cumbernauld now denied to 25MHz equipped aircraft then?

[rans6andrew]

I just went to Cumbernauld website to see what the score is with radio frequencies, what a waste of space. Under "Pilot Info" link says refer to UK Air Pilot. Not a link to the actual info, just refer..... You couldn't get less helpful if you tried.

[Jan Olieslagers]

@BossEyed:
* perhaps you mean 25KHz ? :) (or was it kHz? always confused with all them acronyms and codes and abbreviations)
* what's a DACS?

[PA28181]

what's a DACS?

= Danger Area Crossing Service.

[TCAS FAN]

BossEyed

It is a possibility if you are not 8.33 kHz compliant. However if the crossing/entry/exit point is adjacent to West Wales Airport understand that it may be possible if you are talking to West Wales Information on 122.150 mhz.

Asked the West Wales Radar guys about the 8.33 frequency, they never wanted it. As CAA have apparently run out of 25 kHz channels, its all that was available.

[Sir Niall Dementia]

At the moment most of the 8.33 throughout Europe is allocated to big airport ATIS and clearance delivery. At £20 000 per radio on some of our aircraft it has been a pricey exercise, but IFR rules meant it had to be done.

Although GA is seeing little in the way of change yet, it is coming and more and more frequencies will be changing to 8.33 over the next few years.

SND

[BossEyed]

Jan - oops, yes, I do. What are a few Orders of Magnitude amongst friends? :E

Thanks, everyone, for the clarifications.

[ChickenHouse]

The original question is not precise enough, or better, it is two questions in one.

First, yes, there are now quite some 833-only frequencies in use, especially IFR and talking all Europe, there is no way around 833 capability.

Second and also very important to keep in mind, the equipment on many fields has been changed to 833 radios, even though the old 25 frequency may still be assigned and in use. This also has implications when calling such station with an old 25 radio, as decreased range and degradation of quality. Just for an oversimplified picture: if you send on a 25 frequency with a 25 radio to a 833 station, their much narrower filter will only receive 1/3 of the power you transmit (sorry to the engineers for neglecting formulas for the sake of clearness). We had many complaints at my home field about "bad radio" after we had to switch to a 833 radio and it all turned out to be that mismatch.

[chevvron]

West Wales Radar 127.090 MHZ. They manage Danger Areas in the D201 & D202 block for flying UAVs from West Wales Aberporth when NATS Aberporth not doing so. Was talking to them recently, nice bunch of guys, very helpful, got a direct route through the Danger Areas with a de-confliction service.
You've lost me there.
Isn't 'NATS Aberporth' the NATS staffed ATC radar unit for the Cardigan Bay ranges and 'West Wales Info' the AFIS unit (hence unable to issue clearances) for West Wales Airport aka Aberporth?

[TCAS FAN]

Chevvron

West Wales Radar (WWR) manage Danger Areas when NATS Aberporth is not doing so.

West Wales Radar is a West Wales Airport (WWA) asset, using West Wales Airport sited PSR/SSR/VHF RTF but remoted to Newquay ATCU.

Operating procedures provide for non 8.33 compliant aircraft, whereby an entry into a Danger Area being managed by WWR may be possible by WWA obtaining an entry clearance from WWR and relaying it to the aircraft, which as they will be providing AFIS, they can legally do. This will invariably be for a WWA arrival or departure, although if in the vicinity of WWA may facilitate a DACS. According to WWA the limiting factor is their frequency DOC.

Hope you are no longer lost.

[TheOddOne]

so now that we have all been out and bought nice shiny new radios, with 8.33kHz capability (we have, haven't we?)

Nope. Not yet. Compliance not required for another 17 months. Though with CAA now apparently dishing out 8.33 kHz assignments in UK class 'G' it looks like any further pushing back of the date is increasingly unlikely.

Interesting points are being made about the co-channel interference if using 25kHz spacing equipment. Still don't know if we're going to have to replace our base station set...

TOO

[A and C]

We do not want 8.33 at levels that GA flys, EASA is being forced to contribute to GA 8.33 installation and the last thing we need is then having the excuse to wriggle out of paying us for these expensive radios that we don't need and don't want.

The 8.33 spacing is for the airlines, if they need it then they have to pay........... If it comes down to GA levels we also will have to pay.

[ChickenHouse]

Still don't know if we're going to have to replace our base station set...
Do you have a chance to let the old radio stay? From several airfields I heard they have the obligation to switch the ground stations to 833 technology and I think to remember earlier than the mandate.

[LookingForAJob]

You might want to take a look at this (http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32012R1079&from=EN).
Second and also very important to keep in mind, the equipment on many fields has been changed to 833 radios, even though the old 25 frequency may still be assigned and in use. This also has implications when calling such station with an old 25 radio, as decreased range and degradation of quality. Just for an oversimplified picture: if you send on a 25 frequency with a 25 radio to a 833 station, their much narrower filter will only receive 1/3 of the power you transmit (sorry to the engineers for neglecting formulas for the sake of clearness). We had many complaints at my home field about "bad radio" after we had to switch to a 833 radio and it all turned out to be that mismatch.And if you look at from the other perspective, the broader filters in your old 25 kHz spaced radio are likely to interfere with the comms on two or more 8.33 kHz spaced channels.

[HEATHROW DIRECTOR]

ChickenHouse. It isn't "833" but "8.33", which is somewhat different. HTH.

[Silvaire1]

Amazing that areas of UK need over 760 aircraft communication channels within VHF range to prevent interference ;) That's seven hundred and sixty channels, or apparently two thousand two hundred and eighty aviation channels now required within conflicting VHF range of each other.

[ChickenHouse]

Amazing that areas of UK need over 760 aircraft communication channels within VHF range to prevent interference That's seven hundred and sixty channels, or apparently two thousand two hundred and eighty aviation channels now required within conflicting VHF range of each other.
A controller friend told me that there are two reasons for more channels. One is the missing umbrella european synchronization of frequencies and the other is us, utilizing more and more powerful radios. In the days of 3W and 5W radios range and overlap were not such an issue as today with 10W and 16W.

[LookingForAJob]

A controller friend told me that there are two reasons for more channels. One is the missing umbrella european synchronization of frequencies and the other is us, utilizing more and more powerful radios. In the days of 3W and 5W radios range and overlap were not such an issue as today with 10W and 16W.I guess it just goes to show that controllers don't know everything.

First, coordination of frequency assignments happens in Europe, just as it happens pretty much everywhere else in the world. Read up about the ITU to learn more.

Second, the problem is less the power of radios but more to do with protecting the use of each frequency assignment from interference created by other stations assigned the same frequency. Each assignment has a volume (of airspace) in which it is intended to be used. There is a buffer around each of these volumes in which the same frequency is not assigned to any other ground station - this is intended to ensure that calls by aircraft are only heard by other stations (on the ground or in the air) that are communicating with the ground station with that particular assignment. The greater the altitude that the frequency assignment is designed to cover the bigger the volume that is protected from interference.

Essentially, the problem in our little part of the world is the density of airports, and hence the number of ground stations, that each wants. Add that to the fragmentation of the en-route control system, and the higher levels at which aircraft fly these days compared to just a few years ago, and you might start to understand the reasons for the change to 8.33 kHz spaced channels.

[ChickenHouse]

Essentially, the problem in our little part of the world is the density of airports,
I seriously doubt that. The number of airports is decreasing and all was perfectly fine before with 25k spacing.

[Silvaire1]

I think those who think 760 channels aren't enough due to the density of airports within VHF transmission range should take a look at the Los Angeles Terminal Area Chart.

[BackPacker]

Second and also very important to keep in mind, the equipment on many fields has been changed to 833 radios, even though the old 25 frequency may still be assigned and in use. This also has implications when calling such station with an old 25 radio, as decreased range and degradation of quality. Just for an oversimplified picture: if you send on a 25 frequency with a 25 radio to a 833 station, their much narrower filter will only receive 1/3 of the power you transmit (sorry to the engineers for neglecting formulas for the sake of clearness). We had many complaints at my home field about "bad radio" after we had to switch to a 833 radio and it all turned out to be that mismatch.

I applaud your field for acquiring an 8.33 kHz radio already, while it is probably not needed for a year or so. But I would certainly hope that, until the official switch to 8.33 kHz happens at your field, the radio is still used with the original 25 kHz-separated frequency selected. So things like the bandwidth, transmit power across the bandwidth and selectivity/sensitivity in the receive circuit are not affected.

What you describe is correct for any 25 kHz station wanting to reach an 8.33 station and vice versa. Which is a situation that should not happen: It's why the ITU decided that 25 kHz and 8.33 kHz separated channels would not be called the same, even though they would share the same center frequency.

So even though, for example, 118.200 (a 25 kHz separated frequency centered around 118.200 MHz) and 118.205 (an 8.33 kHz separated frequency centered around 118.200 MHz) share the same center frequency, they will not cooperate properly with each other. And they should not be used simultaneously. People who think they are clever by using their old 25 kHz separated radio, set to 118.200, to communicate with a station advertised as channel 118.205, are really not that clever. Although they may get away with it for a while, before anybody notices.

On a related note, my club recently got a threatening phone call from the authorities again, because one of the club members forgot to include the "Y" in his flight plan. All our aircraft have 8.33 kHz radios since we fly from a controlled field that has switched to 8.33 kHz already. So it was a simple mistake by this club member, but one that the authorities considered serious enough to generate a stiff warning. So if you do have an 8.33 kHz radio (and actually have that setting enabled - it's hidden deep in the setup menus of a GNS430/530 for example) and you do submit a flight plan, don't forget to include the "Y"!

[TelsBoy]

I seriously doubt that. The number of airports is decreasing and all was perfectly fine before with 25k spacing.

With respect, the problem has always been there albeit to a lesser extent in the past.Whilst the number of channels and the spectrum spread itself is finite and fixed, the number of stations is ever-increasing, both within and outside the Aviation world. Incerasing demand for wireless technology places ever-greater strain on what is already a fixed spectrum at full capacity. Shorter channel spacing is therefore the only way to free up more channels for everyone to use.

With respect to the Aviation world, as regional airfields continue to expand and gain additional frequencies (Approach, Radar, Director, Ground, Clearance etc.) the problem has grown exponentially. Additionally the channels that require higher power (like Approach freqs) will therefore interfere with other stations, hence the need for 8.33k.

Outide of Aviation the problem is even greater. Everyone wants mobile phones and 3/4/5G, which uses up more and more of the spectrum. Analogue radio and DAB use up valuable chunks of the spectrum. Wifi, Bluetooth and other short-range wireless systems are starting to have increasing issues with interference because there are too many devices on the same frequency.

Primary Radars have had to be fitted with filters over the past few years as 4G can interfere with the S-Band spectrum.

The problem is very real and is not going to go away until someone can come up with a communication medium not based on radio waves.