31.100 MHz FM 131.8 Hz Fire Mutual Aid Network Test 1405 UTC 29 Dec 2023

[R4002]

Worcester County, Mass. fire mutual aid network radio system test, call outs to individual stations on the network and radio checks.  Test complete at 1407 UTC (907 local time).  Good signal on 31.1000 MHz FM 131.8 Hz PL tone - WQEW233 license / callsign, ID "Worcester Fire" over the air.  31.1 MHz FM PL=131.8Hz.   

Received via G8JNJ online SDR receiver - receiver located in the UK.  Signal strength S5-S7 with minor fading.  Nice FM audio on VHF low band. 

Frequency 31100 kHz FM 31,100 FM 31.1000 FM CTCSS 131.8Hz 131.8 tone


This frequency is used for all sorts of purposes, but it was nice and clear with about a S2-S3 noise floor. 

[R4002]

I did a little research and this is a full repeater, 131.8 Hz CTCSS tone 131.8 PL frequency 31.1000 MHz.  District 8 Fire Operations [Worcester County].    It is patched both to a countywide trunking system and a UHF repeater on 453.7500 MHz, 94.8 Hz PL.   The name of the channel is “OPS” or “Worcester Fire Ops”.  Fire District 8 ops.  So it’s a three-way interconnect, analog low band on 31.1 MHz, analog UHF on 453.750 MHz and digital voice on the trunking system. 

It seems like a very hybrid approach, the county uses a mix of UHF analog, digital trunking and lowband as well as high band VHF.  Lots and lots of 33 MHz band usage for dispatch, tone outs, paging and simulcasting another radio channel or talkgroup.  The 33 MHz band is actually broken down into sub-bands. 


33.020 MHz - 33.100 MHz
and
33.420 MHz - 33.980 MHz

20 kHz spacing (33.02 MHz, 33.04 MHz, 33.06 MHz, 33.08 MHz, 33.10 MHz…up to 33.94 MHz, 33.96 MHz and 33.98 MHz)

are allocated to public safety on a primary basis under Part 90 of the FCC rules.  The 33.120 MHz to 33.4 MHz portion is allocated to business radio.  33.420 MHz is assigned to low power simplex operations as well as operational fixed stations (low power, I believe power is limited to 10 watts or maybe 25w).   


The 31.100 MHz frequency itself is actually assigned to both public safety land mobile users and business radio service land mobile users under Part 90 FCC rules LMR / PMR regulations 31.1 MHz is shared with Public Safety Radio Pool, along with

30.860 MHz
30.900 MHz
30.940 MHz
30.980 MHz
31.020 MHz
31.060 MHz
31.100 MHz (duh)
31.140 MHz


Plus a handful of higher frequencies, namely 35.020 MHz and the old IMTS 35 MHz / 43 MHz pairs. 

[Rob.]

The repeater in on Mt. Wachusett in central MA and covers a large distance. This radio network is very close to my location and have listened to it often.

[R4002]

Awesome.  It often booms in on the UK based and mainland Europe based online SDR receivers. 

31.100 MHz has lots of different traffic on it.  It's not as much as, say, the 31.120 MHz bus/van dispatch repeater (31.12 MHz FM is one of many of those frequencies) but its still quite active.  31.200 is very busy too, sometimes with multiple users coming in at once.  There's a somewhat local to me business user that uses 31.200 MHz and 31.240 MHz (both frequencies 136.5 Hz PL) for grounds maintenance.  A very local (to me) business uses 30.580 MHz, sometimes with carrier squelch (no tone), and ohter times with various tones, 71.9 Hz, 88.5 Hz and I believe a couple others. 

Lowband is certainly alive and well.  For some applications, it is just what the doctor ordered.