HFU HF Underground
Loggings => 10/11 meters => Topic started by: R4002 on August 05, 2017, 1851 UTC
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Checking out some remote SDR receivers for activity on 11 meters elsewhere in the USA. Currently listening to 27.255 MHz CB channel 23 on a remote SDR in Ohio and am noticing a data link or possibly pager transmitter right on frequency. It will transmit an unmodulated carrier for about 1 second, followed by two data bursts about 0.5 seconds apart while "idling" - and when its busy its a series of data bursts. Reminds me of POCSAG. I know this frequency is one of the six available in the 26-27 MHz band under FCC rules Part 95 for data transmission. While the other five frequencies have a maximum carrier power of 4 watts, 27.255 MHz has a maximum carrier power of 25 watts, which means you can do a lot more with it as far as on-site paging systems go.
As my other logs will show, there is heavy use of the 11 meter band for paging systems, on-site pagers for hospitals, etc and for data link systems. I know if one data link system that is sold that uses 27.255 MHz and FSK modulation. I'm hearing bits and pieces of a CB QSO in AM mode underneath the data bursts but it is by far the primary user of this frequency even though band is open and basically every channel is in use.
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I compiled a list of European 26 MHz paging and 27 MHz paging frequencies for the 11 meter band in this thread [https://www.hfunderground.com/board/index.php/topic,35331.0.html (https://www.hfunderground.com/board/index.php/topic,35331.0.html)]
26 MHz paging 26MHz pager 27 MHz paging 27MHz pager 27MHz data link 27.255 MHz 27255 kHz 27.255MHz
After several days of browsing through European based remote SDR receivers, I've noticed heavy use of the 11 meter band for paging activities (among other digital modes). All have been using POCSAG. The UK frequencies are often quite active, as is 27.300 MHz (although I can't figure out where this one comes from). The 27.600 MHz one is based somewhere in Northern Europe and is extremely strong, often pushing past S9+30db signal strength.
The Europeans seem to be a lot more fond of both the FM voice mode and using 11 meters for digital modes and local paging.
26200 kHz / 26.200 MHz - UK Hospital Pager POCSAG
26225 kHz / 26.225 MHz - UK Hospital Pager POCSAG
26250 kHz / 26.250 MHz - UK Hospital Pager POCSAG
26300 kHz / 26.300 MHz - UK Hospital Pager POCSAG
26350 kHz / 26.350 MHz - UK Hospital Pager POCSAG
26715 kHz / 26.715 MHz - UK Paging POCSAG
26745 kHz / 26.745 MHz - UK Paging POCSAG
26750 kHz / 26.750 MHz - UK Paging POCSAG
26755 kHz / 26.755 MHz - UK Paging POCSAG
26785 kHz / 27.785 MHz - UK Paging POCSAG
26835 kHz / 26.835 MHz - POCSAG - unknown origin pager (heard sporadically in UK)
26900 kHz / 26.900 MHz - POCSAG - unknown origin (heard daily in UK, very strong signals)
26945 kHz / 26.945 MHz - Local Paging or On Site Pager 26 MHz band [heard in mainland Europe]
26950 kHz / 26.950 MHz - Local Paging or On Site Pager 26 MHz band
26955 kHz / 26.955 MHz - Local Paging or On Site Pager 26 MHz band [heard in The Netherlands]
27300 kHz / 27.300 MHz - POCSAG Paging (heard daily in UK)
27350 kHz / 27.350 MHz - POCSAG Paging (heard sporadically in UK - unknown origin)
27360 kHz / 27.360 MHz - POCSAG Paging (heard sporadically in UK - unknown origin)
27450 kHz / 27.450 MHz - POCSAG Paging - this frequency seems to be used for basically everything
27550 kHz / 27.550 MHz - POCSAG Paging (with obvious QRM from 27555 USB)
27600 kHz / 27.600 MHz - POCSAG Paging (heard daily in Netherlands)
27650 kHz / 27.650 MHz - POCSAG Paging (heard daily in Netherlands)
27700 kHz / 27.700 MHz - POCSAG Paging (heard daily in Netherlands)
27750 kHz / 27.750 MHz - POCSAG Paging (heard daily in Netherlands)