Primarily for general aviation discussion, but other aviation topics are also welcome.
By Robin500
#1658309
What about Wittering, when does that change? So, what do you read back, the full 3 digits after the decimal, say, decimal zero zero five ( or fife for the purist's)
By chevvron
#1658332
Robin500 wrote:What about Wittering, when does that change? So, what do you read back, the full 3 digits after the decimal, say, decimal zero zero five ( or fife for the purist's)

Are military aifields changing at the moment is the question.
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By The Westmorland Flyer
#1658432
Some airfields are staying on 25kHz for the time being at the request of MOD, to support the Tucano fleet, which is due to be retired at the end of 2019 and is not being equipped with 8.33kHz radios. Carlisle is amongst those that have agreed to do this. I cannot comment on other airfields that may be similarly affected but I believe that there are several.
By chevvron
#1663052
The Westmorland Flyer wrote:Some airfields are staying on 25kHz for the time being at the request of MOD, to support the Tucano fleet, which is due to be retired at the end of 2019 and is not being equipped with 8.33kHz radios. Carlisle is amongst those that have agreed to do this. I cannot comment on other airfields that may be similarly affected but I believe that there are several.

Colerne?
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By TractorBoy
#1663672
Iceman wrote:
James Chan wrote:
to 8.33kHZ channel on the same frequency.


It's not quite the same? You mean to the one nearest to the existing 25Khz frequency? :D


Any 8.33 kHz channel that has a channel offset of 0.005 from its previous 25 kHz frequency, e.g., Blackbushe has gone from a frequency of 122.300 MHz to the 8.33 kHz channel 122.305, similarly xzy.a25 to xyz.a30, xzy.a50 to xyz.a55, and xzy.a75 to xyz.a80 has not changed frequency at all. All of these 8.33 kHz channels are using exactly the same frequency as they did before, e.g., Blackbushe is still radiating and receiving on a frequency of 122.300 MHz. The channel offset of 0.005 does not change the frequency by an increment of 8.33 kHz, it merely instructs the transceiver to limits its transmit and receive bandwidths to an 8.33 kHz channel spacing based on the 25 kHz frequency.

To get a genuinely new frequency in 8.33 kHz land, you'd have to be using one of the new 0.010 or 0.015 channel offsets from a 25 kHz frequency designator, the new frequencies then being 8.33 kHz and 16.66 kHz offset from a 25 kHz frequency.

Iceman 8)


This.

People seem to be misunderstanding what the change actually means. For example, North Weald went form 123.525 to 123.53.

The frequency itself stays the same (123.525) but the new number - effectively now a channel number, not a frequency - is to tell the comms unit to operate at 123.525 but over a 8.333KHz bandwidth. If you dial in 123.525, it will still transmit at the same frequency but at 25kHz bandwidth.

If the transmitter is incorrectly set to 25Khz b/w and the receiver is 8.333, then the receiver may lose some of the signal, and the signal may stomp on the new channels (if active) either side.

If the receiver is incorrectly set to 25KHz and the transmitter to 8.333, then the receiver will hear the signal fine. But of course it may also receive the new channels (if active) either side.

I hope..!
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By riverrock
#1663680
TractorBoy wrote:If the transmitter is incorrectly set to 25Khz b/w and the receiver is 8.333, then the receiver may lose some of the signal, and the signal may stomp on the new channels (if active) either side.

yes - other than this bit.

Transmitter is the same when set to 25 or 8.33kHz spacing. However the allowed tolerances for old 25kHz radios are larger than the tolerances for newer 8.33kHz radios, so its possible (if unlikely) that your old 25kHz radio can't be received by someone receiving with 8.33 spacing.
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By segillum
#1663758
Spoke to Blackpool ATC this afternoon. They're still using 25kHz frequencies and don't know yet when they're going to 8.33kHz channels.