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UBC XLT125 new 8.33 frequencies

PostPosted: Sat Jan 12, 2019 6:27 am
by stevieiz
Morning folks,

Recently my local, Inverness EGPE changed from Twr 118.40 to 118.405 and App 122.60 to 122.605.

I cant seem to program these into the scanner. Does this matter as I still pick up signal on the old frequencies.

Thanks

Steve

Re: UBC XLT125 new frequencies

PostPosted: Sat Jan 12, 2019 10:01 am
by Minus1
If this forum had a FAQ about 8.33 kHz frequencies we wouldn't need to keep answering questions like this forever. :rolleyes:

No, it doesn't matter.
118.405 is not a frequency - it is an 8.33 channel using a frequency of 118.4
122.605 is not a frequency - it is an 8.33 channel using a frequency of 122.6

I prefer to write 118:405 and 122:605 to make this clear, but the powers-that-be don't have that much gumption.

Re: UBC XLT125 new frequencies

PostPosted: Sat Jan 12, 2019 1:23 pm
by stevieiz
Thanks for the clarification.

Re: UBC XLT125 new 8.33 frequencies

PostPosted: Sun Jan 13, 2019 1:58 am
by mhm
It does not matter for your scanner. The new freq only affects the aircraft transmitting.

Re: UBC XLT125 new 8.33 frequencies

PostPosted: Sun Jan 13, 2019 8:55 am
by m0lsx
mhm wrote:It does not matter for your scanner. The new freq only affects the aircraft transmitting.


It does NOT effect transmitting or receive. It only effects what the control tower says to the pilot.
These so called new 8.33 khz frequency steps are just a totally stupid way of saying a different frequency.

Re: UBC XLT125 new 8.33 frequencies

PostPosted: Sun Jan 13, 2019 10:56 am
by Chris P
As I said earlier and will probably have to say many more times lol

the channel designation is "dialled" on an 8.33Khz aircraft transceiver but the actual frequency ( which is transmitted or received ) in EACH 100Khz segment of the VHF airband is as below . Your scanner should be set to the frequency (assuming it has the 8.33 step capability)

Channel Frequency
118.005 118.0000
118.010 118.00833
118.015 118.0166
118.030 118.0250
118.035 118.0333
118.040 118.04166
118.055 118.0500
118.060 118.05833
118.065 118.06666
118.080 118.0750
118.085 118.08333
118.090 118.09166
118.105 118.1000

So if a channel designation is XXX.005 you set your scanner to XXX.0000 and if channel designation is XXX.010 you set your scanner to XXX.00833 and so on

Re: UBC XLT125 new 8.33 frequencies

PostPosted: Sun Jan 13, 2019 10:58 am
by Minus1
8.33 kHz channels are NOT frequencies. They are channels, the channel numbers are close to the frequencies but they are not exact.
Use of an 8.33 kHz channel affects both transmission and reception because it uses a narrower bandwidth.
This Eurocontrol document gives examples:
https://www.eurocontrol.int/sites/defau ... 0table.pdf

But we will doubtless have to go on explaining this forever, due to the moronically stupid decision to use 8.33333333333333333333333333333333333333333 kHz as a frequency step. :rolleyes:

As I've said before, quoting 8.33 channels as "118:005" using a semi-colon as a separator, makes it clear that it is not a decimal number, and thus not a frequency; and distinguishes them from 25 kHz frequencies such as "118.025".

RT procedure could adopt "118 channel 005" as it is no slower, and arguably faster, to say than "118 decimal 005".

Re: UBC XLT125 new 8.33 frequencies

PostPosted: Mon Jan 14, 2019 8:19 pm
by Scan125
I doubt this continual confusion is ever going to go away. And no I'm not pointing at users out there. They see xxx.yyy being officially published and punch xxx.yyy into their kit. For some with partly 8.33 compliant kit they will be OK *IF* they ignore what some scanners redisplay after they have punched those numbers. For non either partially or fully compliant 8.33 kit they will hear nothing and not know what is going on.

Even sometimes I get a little confused when dabbling with my UBC125XLT and my Yaesu FTA-250.

Ideally they should have gone like the marine/cb band and allocated absolute channel number 1 ….. 9999 and then they could use any frequency on any channel they liked. But world wide aero radio comms are more entrenched in a base frequency and 25kHz step so splitting up the band became a dogs dinner.

The traditional absolute frequency dials for aircraft comms kit, when converted to 8.33 compliance just became a pseudo channel for some frequencies but not for others.

As I've said before pilots do not really care. They are told to contact xyz on nnn.yyy and all they care about is that both parties are aligned to connect. Absolute frequency used is irrelevant when using compliant kit.

Re: UBC XLT125 new 8.33 frequencies

PostPosted: Thu Feb 07, 2019 12:29 am
by Steve
Here are all the changes in an easy to understand chart showing Old 25kHz Frequency, New Channel Name and Actual Frequency (From 2019)
https://ukradiotransmissions.wordpress. ... planation/

Image

Re: UBC XLT125 new 8.33 frequencies

PostPosted: Thu Feb 07, 2019 4:43 pm
by JohnUK
Steve wrote:Here are all the changes in an easy to understand chart showing Old 25kHz Frequency, New Channel Name and Actual Frequency (From 2019)
https://ukradiotransmissions.wordpress. ... planation/

Nice choice of images :laughs: