Radio frequencies

[jonjorobb]

Hi,

134.460 is the Sector 24 frequency. it has not replaced 132.840, as this is the Sector 1 Frequency.

118.480 is Sector 14, my site has it listed as 118.840, I'll fix this now.

I will also change Sector 16 as well, as you say it is now 134.455.

Sector 27 & 32 are quite interesting, as they are actually the same airspace. Sector 27 handles London TMA (Excluding Gatwick) Arrivals, Whilst Sector 32 handles all other traffic and Gatwick Arrivals. Sector 27 is on 129.205, whilst Sector 32 is 131.130 . When bandboxed, I'm quite sure there on 129.205

Thanks everyone,
Jonjo

[jonjorobb]

Actually, I'm quite sure Sector 16 is 136.600. The frequency changed to make way for 134.460 as there too close.

Thanks, Jonjo

[meagain]

For ground listeners channel 127.430 and freq 127.425 are on the same frequency 127.425.
So are 118.480 and 118.475.
The difference is in the airborne receiver where 8.33s have a narrower filter than 25 kHz freqs.
127.415 (127.41666) and 127.435 (127.43333) would be the adjacent channels in 8.33 kHz spacing.

[dca]

Actually, I'm quite sure Sector 16 is 136.600. The frequency changed to make way for 134.460 as there too close.

Thanks, Jonjo

H Jonjo,

• I'm also sure that 134.460 replaced 132.840 (London Upper) although both frequencies operate still. Where do you have S24 covering? (I'm right underneath the 134.46 sector which hands over to 127.43 around the LGW area)
• S16 was 134.45, changed to 134.46

Interesting debate though as there is no definitive list (thats up to date, anyway!) out there. As well as by listening I pick up the changes through the AIRAC cycles on the NATS www.

Cheers,

Dave

[dca]

Sorry I should have said S16 was changed from 134.45 to 134.455...

[jonjorobb]

Hi,

Sector 24 was introduced early last year, which replaces the top half of Sector 1. If you look at the map on my site, imagine Sector 24 as the top half of what is Sector 1 on that map. They are old maps and im currently trying to work out a way of making sector maps myself, as I have the lat/long coordinates of all the sectors however I havent found a way to make up to date maps as yet. Sector 1 is 132.840 and Sector 24 is 134.460 . Because this is part of what was Sector 1, This will be why you thought it had replaced 132.840.

Ovbiously the AIRAC's are a great way to keep track of frequency changes. If I remember correctly, Sector 16's frequency changed to 134.455 late 2008, but changed to 136.600 early 2009 as Sector 24 was being introduced on 134.460, which is only 5KHz away, and they were expecting interference.

The list on my website is updated when the AIRAC's are released, and I try to make it as accurate as possible, However ovbiously this can be quite a hard task. The last frequency change was the introduction of 128.815 as an Area Control Sector as far as I know.

Indeed, An interesting debate!
Jonjo

[dca]

Thanks Jonjo,

Great info & A great website!

Dave

[meagain]

134.455 and 134.460 are 8.33 kHz apart, not 5 kHz.

134.455 = 134.450 MHz
134.460 = 134.458333 MHz

[jonjorobb]

Even so, En-route frequencies are transmitted at an offset, sometimes as much as 7.5KHz. Depending on the transmitters etc. that could cause interference.

[Brisbane]

To DeeJay, 135.05 is supposed to be operational between KATHY and AVANT and then 127.825 from KATHY to ORTAC. From personal experience, they just use 127.825 for the whole sector.

[DeeJay]

Brisbane.Thanks for that info, have listened out on 127.825, but only get the aircraft end. Until early 2009, could hear both ends of 135.05, and had done for some years. As mentioned, they must have shifted to another transmitter site.

[meagain]

Even so, En-route frequencies are transmitted at an offset, sometimes as much as 7.5KHz. Depending on the transmitters etc. that could cause interference.

Used for 25 kHz frequencies only so multiple transmitter sites can be used without interference. 8.33 kHz freqs are always spot on.

[jonjorobb]

Hi meagain,

thanks for the information. When you say 8.33 kHz are always spot on, does this not cause interference with other transmitters?

Thanks,
Jonjo

[meagain]

8.33 kHz channels are protected. One transmitter per active freq/sector only.  Therefore usage in upper airspace only. If multiple usage than sectors are widely separated, e.g. 133.955 is Maastricht and Madrid,

25 kHz freqs can have multiple transmitters for better low altitude coverage. Freq offset is something like +- 3.5 kHz. No two transmitters on exactly the same freq.

[jonjorobb]

Hi meagain,

Thanks for explaining that! So, if I understand correctly, London Control 132.860 transmits on 132.8583?

Thanks again,
Jonjo