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CB CH19 / AM - Data Burst

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  • 21-12-2020 5:17pm
    #1
    ironclaw
    Registered Users Posts: 8,004 ✭✭✭


    Recently dusted off a CB and set it to CH19 (AM). I noticed that every minute or so there is a data burst. I don't recognise the pattern but it's roughly the same each time.

    I'm in North Wicklow / Bray and it's perfectly clear.

    Any idea what it is?


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    #2
    orm0nd
    Registered Users Posts: 4,174 ✭✭✭orm0nd


    Christmas lights?


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    #3
    ironclaw
    Registered Users Posts: 8,004 ✭✭✭ironclaw


    orm0nd wrote: »
    Christmas lights?

    Do you mean as a controller? I doubt it but I'm open to correction.

    As interference, no, it's definitely a machine-generated data burst.


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    #4
    jmcc
    Registered Users Posts: 7,295 ✭✭✭jmcc


    Old pager system? Some of the hospitals used to use 27 MHz for their pager systems. There may be an hidden/alpha channel between 19 and 20 and this could be interference from a transmitter on that alpha channel.

    Regards...jmcc


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    #5
    ironclaw
    Registered Users Posts: 8,004 ✭✭✭ironclaw


    jmcc wrote: »
    Old pager system? Some of the hospitals used to use 27 MHz for their pager systems.

    Regards...jmcc

    Could be, the most likely candidate to be honest. Seems odd to use a public CB channel for that though.


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    #6
    jmcc
    Registered Users Posts: 7,295 ✭✭✭jmcc


    ironclaw wrote: »
    Could be, the most likely candidate to be honest. Seems odd to use a public CB channel for that though.
    Think that it is even used to broadcast Mass on some channels. The old POCSAG Eirpage system was shut down a few years ago as a lot of stuff switched to using SMS. One one of the Ham Facebook groups there were reports from Spain about Irish hospital pagers on CB frequency being picked up. That was only a year or two ago. The old pager networks were more robust than mobile phone systems or TETRA as they are one-way in RF terms.

    Regards...jmcc


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    #7
    Antenna
    Registered Users Posts: 2,305 ✭✭✭Antenna


    I heard what seems the same thing as the OP describes on 27.185 MHz (ch 19) a couple of times in recent days..

    and I am over 120 miles roughly south west !

    A scanner left on in the background stopped on it a few times.
    not significant strength but enough to stop scan on this scanner with outdoor aerial for VHF.
    (I have had CB frequencies programmed in on that scanner just to see was there any local activity in the past few months)


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    #8
    ironclaw
    Registered Users Posts: 8,004 ✭✭✭ironclaw


    jmcc wrote: »
    POCSAG Eirpage

    That's a blast from the past there. I vaguely remember running a decoder in my laptop many years ago.

    Good (analogue) times!


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    #9
    jmcc
    Registered Users Posts: 7,295 ✭✭✭jmcc


    ironclaw wrote: »
    That's a blast from the past there. I vaguely remember running a decoder in my laptop many years ago.

    Good (analogue) times!
    Remember firing up an SDR for testing a few years ago and wondering why I couldn't get an Eirpage sigal or an RTE signal on Medium Wave. They'd been closed down. :) Lots of analogue stuff still around though but it is a much more noisier RF environment.

    Regards...jmcc


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    #10
    Antenna
    Registered Users Posts: 2,305 ✭✭✭Antenna


    I don't believe it could be the same transmission (as the OP) I am hearing, it appears to be more nearby. POCSAG type pager sounds ....

    The one I hear transmits for about 10 seconds, then after a pause of five minutes (from the end of transmission) will do so again (beaconing) - constantly
    27185kHz and its NFM (not AM)

    PS: monitored this whilst travelling. Came up relatively strongly passing the Carrigtwohill-Glounthaune area (Co. Cork) on N25.
    There was no sign of it last night but back on this morning every approx 5 minutes


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