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Topics - R4002

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16
Hearing the usual chatty fishermen on 31.000 MHz FM [CSQ] at 1215 local time / 1615 UTC.  31.0 MHz NFM 31000 FM carrier squelch (no squelch tone used). 

Interesting time for these guys to be coming in, usually they're stronger in the morning or evening, vs. middle of the day.  Chances are the other frequencies may start becoming active shortly too.

Fishing trawlers high HF band / VHF lowband FM radiotelephone system, originally out of China:


Original specification:
27.500 MHz to 39.475 MHz - 27.5MHz - 39.5MHz
25 kHz spacing, FM voice 16K0F3E emission
Channelized
480 channels, straight sequence

27.500 MHz FM - Channel 001
27.525 MHz FM - Channel 002
27.550 MHz FM - Channel 003
27.575 MHz FM - Channel 004
and so on (up through 10 meters) up to

39.425 MHz FM - Channel 478
39.450 MHz FM - Channel 479
39.475 MHz FM - Channel 480

Power output 25w.  Dual mode signalling, 300 baud and 1200 audio-frequency shift keying for individual calling, ship to ship call, emergency call, ship to shore station call, group call, fleet broadcast signal and other purposes.  System is entirely carrier squelch operated.

There are modified variants sold out of Taiwan and other places that use 12.5 kHz spacing to increase the number of channels to 960, and use the same selective calling systems.  Lots and lots of these radios around, likely in use worldwide.  31.000 MHz is one of the more popular frequencies, I've heard them down below 28.000 MHz, inside 10 meters, and on 29.750 MHz FM, 29.775 MHz FM, 29.800 MHz FM, 29.825 MHz FM, 29.850 MHz FM, 29.875 MHz FM and many others, including 30.000 MHz FM.  29.825MHz and 29.875MHz are very popular ones.  The 12.5 kHz "extra channels" aren't as busy but they are certainly in use.  I've logged 29.9375 MHz, 29.9625 MHz, 29.9875 MHz, 30.0125 MHz, 30.1875 MHz, 32.1125 MHz, 32.1375 MHz, and many many others.  Seems like the FM deviation is lowered when operating on the 12.5 kHz channels...except on some radios its not. 

17
Nice signal from the taxi lady Juanita on 26.765 MHz AM 26765kHz AM 26.7650 MHz AM late this morning (U.S. East Coast). 

SIO 333 or so at 1555 UTC / 1600 UTC or 1155 / 1200 noon local time.  Local receive in Richmond, Virginia.

Checking the W3HFU and N1NTE SDRs, her transmitter seems to be a bit more off frequency than usual...carrier offset 26764.4 kHz 26.764.4 MHz.  On the N1NTE SDR, one of the drivers replying to the taxi dispatcher is off-frequency in the other direction, carrier on 26765.6 kHz. 

Of all the Spanish language taxi cab radio systems operating in the 25-50 MHz range, this one is one of the most consistent, right up there with 31.200 MHz FM 203.5 Hz PL tone and the Costa Rican taxi cab radio dispatch system out of Alajuela Costa Rica on 32.180 MHz and 32.940 MHz 77.0 Hz PL and 141.3 Hz PL. 




18
10/11 meters / 26.805 MHz FM Activity 1430 UTC 22 March 2024
« on: March 22, 2024, 1434 UTC »
26.805 MHz FM very much alive this morning (U.S. East Coast). 


19
I can hear 26.755, 26.745 and 26.695 locally in Richmond VA using a handheld.

On the W3HFU SDR - specifically the one with the 900 foot sky loop antenna

26.950 MHz FM - Weak paging signals
26.900 MHz FM - Pager signals, POCSAG - barely above the noise
26.855 MHz FM - Pager signal bursts, likely offset freq for 26.85 MHz
26.850 MHz FM - Paging bursts, severe QRM from CB traffic on 26.845 MHz and 26.855 MHz
26.755 MHz FM - POCSAG bursts, sporadic
26.750 MHz FM - POCSAG signals, other data bursts (same data signals noted on 26.65 MHz)
26.745 MHz FM - Constant paging signals, first tuned in around 1600 UTC.  Signal strength increased around 1630 UTC
26.695 MHz FM - Constant pager signals, POCSAG
26.650 MHz FM - Paging bursts, narrow band (4-5 kHz wide BW), similar to some of the signals on 26.750 MHz
26.600 MHz FM - Paging signals noted around 1650 UTC and 1655 UTC
26.500 MHz FM - Constant FM "idle" signal, reminds me of 26.200 MHz and 27.450 MHz (both European paging systems)
26.500 MHz FM - POCSAG paging signals
26.450 MHz FM - POCSAG - narrowband signals, weak to fair at 1650 UTC - 1655 UTC
26.250 MHz FM - POCSAG paging signals, mostly narrowband, sporadic, wide band (12 kHz BW) noted at 1658 UTC
26.200 MHz FM - Constant FM "idle" signal, being sent even when paging transmissions are sent - POCSAG (12 to 14 kHz bandwidth!)

20
Received locally in Richmond, VA with a PNI Escort HP 82 handheld CB radio with a telescopic whip antenna (Cobra HA-TA). 

https://www.youtube.com/watch?v=pG9v8Jc4NgY

^quick video clip of it.  Very heavy fading.

UK FM CB channel 7, frequency 27.66125 MHz FM 27661 FM CADS WPAS LW07 frequency 27.661 MHz FM


21
26.765 MHz AM - likely Mexico location Mexican taxi cab dispatcher YL "Juanita" coming in nicely at 1940 UTC.  Tuned in earlier at approx 1800 UTC with a SIO 333 signal.  Other taxi cab comms coming in all over the band, as it to be expected:

YL dispatcher - taxi cab company land mobile radio, Spanish language radio taxi for all frequencies below

25.625 MHz AM
25.695 MHz AM
25.795 MHz AM
25.835 MHz AM
25.875 MHz AM
25.945 MHz AM - STL carrier (unmodulated FM signal) on 25.950 MHz coming in with it
25.965 MHz AM
25.995 MHz AM
26.035 MHz AM
26.065 MHz AM
26.115 MHz AM
26.145 MHz AM - with sporadic QRM from strong FSK bursts on this frequency 26145 kHz
26.165 MHz AM
26.175 MHz AM - QRM from FSK signals on this frequency too 26175 kHz
26.185 MHz AM
26.255 MHz AM
26.335 MHz AM
26.405 MHz AM
26.505 MHz AM
26.515 MHz AM
26.655 MHz AM
26.685 MHz AM
26.695 MHz AM - noting some stronger QRM from UK based paging systems on here POCSAG
26.755 MHz AM
26.765 MHz AM
26.795 MHz AM
26.935 MHz AM
26.945 MHz AM - QRM from US freeband stations

27.485 MHz AM - severe SSB QRM
27.515 MHz AM - severe SSB QRM
27.525 MHz AM - severe SSB QRM
27.735 MHz AM
27.755 MHz AM
27.765 MHz AM
27.775 MHz AM
27.785 MHz AM - QRM with UK FM CB
27.805 MHz AM
27.815 MHz AM
27.835 MHz AM
27.855 MHz AM severe QRM
27.875 MHz AM

22

UK paging systems coming in (barely) on 26.695 MHz, 26.745 MHz, 26.750 MHz and 26.755 MHz.  26745 is the best signal at 1930 UTC.

Nothing noted on the lower 26 MHz paging frequencies, including 26.200 MHz, 26.220 MHz, 26.250 MHz, 26.300 MHz, 26.350 MHz, 26.400 MHz, 26.450 MHz, 26.500 MHz, 26.550 MHz (26.555 MHz LSB is going nuts), 26.600 MHz...26.650 MHz has some very weak POCSAG

UK FM CB:

27601 FM - UK FM CB Channel 1 - freq 27.60125 MHz FM - very dramatic fading
27611 FM - UK FM CB Channel 2 - freq 27.61125 MHz FM - noted UK accents, severe SSB QRM
27631 FM - UK FM CB Channel 4 - freq 27.63125 MHz FM - weak, severe QRM from 27.630 MHz and 27.635 MHz
27731 FM - UK FM CB Channel 14 - freq 27.73125 MHz FM - weak, but there, QRM from taxi cab on 27.735 MHz AM and SSB freebanders
27781 FM - UK FM CB Channel 19 - freq 27.78125 MHz FM - oh yeah, the busy one.  Taxi cab dispatcher YL QRM from 27.775 MHz AM and 27.785 MHz AM
27841 FM - UK FM CB Channel 25 - freq 27.84125 MHz FM - noted activity on this frequency quite often, taxi cab QRM from 27.845 MHz AM
27851 FM - UK FM CB Channel 26 - freq 27.85125 MHz FM - severe QRM from 27.855 MHz LSB
27891 FM - UK FM CB Channel 30 - freq 27.89125 MHz FM - some activity, as expected lots of Spanish language QRM
27911 FM - UK FM CB Channel 32 - freq 27.91125 MHz FM - some activity, U.S. truckers on 27.905 MHz causing issues
27951 FM - UK FM CB Channel 36 - freq 27.95125 MHz FM - FM carrier on frequency, American freeband CB on 27.955 MHz AM
27961 FM - UK FM CB Channel 37 - freq 27.96125 MHz FM - very heavy accents
27991 FM - UK FM CB Channel 40 - freq 27.99125 MHz FM - some very sporadic activity noted

23
SIO 333 signals, received locally (Richmond, VA).  Talking about different trucking companies and general informal chatter.  Nice sounding AM signals, no overmodulation, splatter or insane amounts of echo. 

26735 kHz AM 26.735MHz AM.  U.S. truckers on export radios out of band CB radio free band CB 11 meter truck radios. 

26.735 MHz AM is CB radio channel 19 "down one band"....which is one of the reasons why 26.735 MHz AM is so popular for long-haul truckers.  Same with channel 19 "up one band" - 27.635 MHz AM.

26735kHz free band CB radio frequency "low channels" or "Band C". 


24
Via G8JNJ SDR. 

Two distinct data signals - center frequency is 27760 kHz 27.76 MHz, lower side data signal is centered at approx. 27.757 MHz or 27.758 MHz and the high side data signal is centered at approx. 27.762 MHz or 27.763 MHz. 

Overall bandwidth is almost exactly 10 kHz...looks like its closer to 9.5 kHz. 

Video link:

https://www.youtube.com/watch?v=PR7WsFErip8


25
10/11 meters / Fishing Fleet Comms 27.5 MHz - 30 MHz
« on: March 15, 2024, 1416 UTC »
Listening to the G8JNJ SDR this morning...lots of Asian fishermen chatting away

27.500 MHz FM - I believe this is the first time I've heard them on Channel 001, 27.5 MHz FM.
27.525 MHz FM
27.625 MHz FM
27.675 MHz FM
27.700 MHz FM
27.725 MHz FM
27.750 MHz FM
27.825 MHz FM
27.850 MHz FM
27.925 MHz FM
27.950 MHz FM
27.975 MHz FM
28.325 MHz FM
28.375 MHz FM
28.525 MHz FM
28.5375 MHz NFM
28.625 MHz FM
28.700 MHz FM
28.725 MHz FM
28.825 MHz FM
28.875 MHz FM
28.925 MHz FM
28.975 MHz FM
29.000 MHz FM
29.025 MHz FM
29.150 MHz FM
29.200 MHz FM
29.225 MHz FM
29.325 MHz FM
29.425 MHz FM
29.700 MHz FM
29.7375 MHz NFM
29.750 MHz FM
29.775 MHz FM
29.825 MHz FM
29.875 MHz FM
29.9375 MHz NFM
29.9625 MHz NFM
29.975 MHz FM
29.9875 MHz NFM
30.0125 MHz NFM
30.025 MHz FM

and so on

lots of 12.5 kHz narrowband channels active today above 30 MHz, honorable mentions include 30.1875 MHz, 30.3375 MHz, 30.6375 MHz, 30.7875 MHz, 31.6375 MHz, 31.7375 MHz, 31.7625 MHz, 31.7875 MHz, 32.0375 MHz, 32.0875 MHz, 32.1375 MHz, 32.1875 MHz, 32.2125 MHz, 32.9125 MHz, 32.9375 MHz

26
Via G8JNJ SDR

27
Listening via the G8JNJ SDR this morning - 1310 UTC.  29875 FM coming in SIO 444 to SIO 555, nice strong FM signals.  29750 FM 29.75 MHz FM also with some more dramatic fading. 

29.8750 MHz FM [CSQ] going basically nonstop at 1315 UTC.  Sounds like Japanese.   Fishery radio fisheries radio chatter comms 29,875 29.875MHz FM

28
Hello all,

This is an interesting one, now that I’ve managed to catch the voice transmissions as well as the paging data. 

The voice messages include a “tone out” (possibly a selective calling tone) burst prior to the voice message.  Frequency is 27.885 MHz. 

The recordings linked below were all made via an online SDR in the UK, specifically the G8JNJ SDRs:

27.885 MHz FM Alert Tones Voice Message + Paging Signals [Part 1] G8JNJ SDR - 27 Feb 2024
https://youtu.be/FlRQfJUgLBI

and

27.885 MHz FM Alert Tones Voice Message + Paging Signals [Part 2] G8JNJ SDR - 27 Feb 2024
https://youtu.be/VUbcwUtgOiA


Voice message for “Part 2” begins at the very beginning of the video. 

For “Part 1” there is an in-progress voice message when I start recording.  At 0:28 in, you can hear the “tone out” burst - one long tone followed by two short tones…followed immediately by a voice message.   


Numerous other videos of the paging signals - including the various bandwidth POCSAG signals on frequency have been captured and are on the regular “R4002” page. 


The links above are the best capture I’ve gotten of the voice messages though. Here are the other two videos of the voice message:

27.885 MHz FM Data Paging + FM Voice Transmission UNID Source [G8JNJ SDR] 23 Feb 2024 [Part 1]
https://youtu.be/bFesHLxAHvc

^ voice transmission in progress at the very beginning of the recording.  This one is the worst quality of the clips I managed to get.  There is a “Part 2” video from 02/23/2024 but it only shows data / paging signals and increasing QRM from freeband CB radio signals on 27.880 MHz USB, 27.885 MHz LSB and 27.885 MHz AM - U.S. out of band 11 meter CB signals starting to fade in.

Older video / audio recordings of the voice paging pager / POCSAG paging on 27885 FM:

27.885 MHz FM POCSAG Paging + FM Voice Pager 27MHz Band 11M Band [G8JNJ SDR in UK] - 15-Dec-2023
https://youtu.be/C6R50M8Q-dY

^ from December 15th, 2023.  Tone out / alert tone at 0:16 in, follows the same format - one long tone burst followed by two short tone bursts followed by a voice message transmission (FM mode) followed by a moment of unmodulated FM carrier…then it switches back to paging data bursts. 

27.885 MHz FM Voice Paging + Data Bursts Pager System POCSAG Paging - Via G8JNJ SDR - 24 Oct 2023
https://youtu.be/g-8CHON_QxU

^ from October 24, 2023.  The voice message is in progress when the recording starts. 


 
 


 




 

29
10/11 meters / UK FM CB Activity 1945 UTC 26 Feb 2024
« on: February 26, 2024, 2027 UTC »
The band is lighting up this afternoon.  Lots of activity on UK FM CB radio channel 19, plus numerous others:

27.601 FM 27.60125 MHz FM - UK FM CB Channel 1 - FM carriers and voice, lots of SSB QRM - possibly music carriers?
27.631 FM 27.63125 MHz FM - UK FM CB Channel 4 - unmodulated FM carrier (???), QRM from 27.635 MHz
27.681 FM 27.70125 MHz FM - UK FM CB Channel 9 - another carrier - tons of QRM
27.731 FM 27.73125 MHz FM - UK FM CB Channel 14
27.751 FM 27.75125 MHz FM - UK FM CB Channel 16
27.781 FM 27.78125 MHz FM - UK FM CB Channel 19
27.791 FM 27.79125 MHz FM - UK FM CB Channel 20
27.831 FM 27.83125 MHz FM - UK FM CB Channel 24 - busy, QRM from AM freeband CB signals on 27.835 MHz
27.841 FM 27.84125 MHz FM - UK FM CB Channel 25 with QRM from 27.845 MHz AM taxi cab dispatch
27.861 FM 27.86125 MHz FM - UK FM CB Channel 27
27.901 FM 27.90125 MHz FM - UK FM CB Channel 31
27.911 FM 27.91125 MHz FM - UK FM CB Channel 32
27.921 FM 27.92125 MHz FM - UK FM CB Channel 33 with QRM from 27.915 MHz AM and 27.925 MHz AM truck drivers
27.931 FM 27.93125 MHz FM - UK FM CB Channel 34
27.951 FM 27.95125 MHz FM - UK FM CB Channel 36
27.961 FM 27.96125 MHz FM - UK FM CB Channel 37
27.971 FM 27.97125 MHz FM - UK FM CB Channel 38 - calling frequency
27.981 FM 27.98125 MHz FM - UK FM CB Channel 39
27.991 FM 27.99125 MHz FM - UK FM CB Channel 40

27.841 FM (UK FM CB Channel 25) is actually as busy as 27.781 FM.  Unfortunately there's enough Latin American taxi cab comms starting to come in that the AM mode land mobile comms QRM is becoming a thing, especially on 27.78125MHz

Plenty of in-band activity and SSB all over the place.  26.805 MHz FM active as well.   

UK paging pager signals POCSAG on 26.745 MHz, 26.705 MHz, 26.695 MHz, 26.350 MHz, 26.250 MHz and 26.200 MHz. 

30
10/11 meters / Class C CB (RCRS) 27 MHz Telemetry Yahoo Group Archive
« on: February 26, 2024, 1816 UTC »
Info from the VHFDX email chain, good group of 25-30 MHz and VHF low band DXers (as well as other bands, including 22m interest).  Given the amount of data traffic on 27.255 MHz and the other RCRS frequencies, I wanted to share this with the HFU forums so this link is archived

https://web.archive.org/web/20201214034230/https://groups.yahoo.com/neo/groups/Class_C_Telemetry/info

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