andyreagan.com

• RTL-SDR v4 (bought this initially).
• Airspy https://itead.cc/product/airspy/

The airspy would capture more bandwidth, in cases where the RTL-SDR needs two units for bandwidth.

Really good description of how P25 works: https://www.mathworks.com/help/comm/ug/p25-spectrum-sensing-with-synthesized-and-captured-data.html Example python code to see if it's present from "raw" recordings: https://github.com/777arc/PySDR/issues/18#issuecomment-2015779302

• SDR++ user guide: https://www.sdrpp.org/manual.pdf
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I got this up and running really easily!

CoMIRS stuff:

https://www.radioreference.com/db/sid/7127

cache

System Name: Commonwealth Of Massachusetts Interoperable Radio System (CoMIRS) Location: Regional, MA County: 8 Counties System Type: Project 25 Phase II System Voice: APCO-25 Common Air Interface Exclusive System ID: Sysid: D14 WACN: BEE00 Last Updated: October 23, 2024, 11:11 am UTC [Updated System Description Text] System Notes Massachusetts State Police operate two radio systems, an analog trunked system, heard east of the Connecticut River, and Mount Greylock, and a newly implemented digital system, which is slowly growing to cover the entire commonwealth.

Cities like Cambridge, Worcester, Boston, and special systems such as MassPort can only be heard on their respective closest systems

Talkgroups which begin with "6 - - - -" (i.e. 65102), and are five digits, are dynamic talkgroups that are assigned when another linked system's user has connected with the CoMIRS radio system. They are never permanent, despite how frequently they may occur.

Red (c) are control channel capable frequencies

And for franklin county:

Franklin county:

https://www.radioreference.com/db/browse/ctid/1218 cache

Shutesbury:

CoMIRS

• https://www.snewiki.com/wiki/index.php/Massachusetts_Commonwealth_Interoperability_Radio_System
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CoMIRS - Commonwealth of Massachusetts Interoperability Radio System

Motorola P25 Phase I (FDMA)/Phase II (TDMA) hybrid system. System ID: D14 WACN: BEE00 NAC: Multiple - NAC Varies by Site Massachusetts P25 trunked system. For the Massachusetts State Police Analog system primary page, click here To convert the P25 talkgroup to see if it matches an "analog" talk group, multiply the TG by 16. (i.e. 2209*16=35344) Sites have had analog emissions designators added to their FCC licenses, and may be mixed use. To see a list of ALL TALK GROUPS used on the CoMIRS system, including on the campus sites (Cambridge, Worcester, etc.), please Click Here

For "Warwick" frequencies:

Franklin County talk groups:

• Operations channels are available to police and fire agencies.
• The 22xx and 23xx Talk Groups may be inactive as they were used for system capacity testing.

For the analog, it would be 3697*16 = 59152 So it's actually the analog system, not digital.

Analog system

• https://www.snewiki.com/wiki/index.php/Massachusetts_State_Police
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This page is for the legacy analog system. This system is slowly being replaced by CoMIRS (Mass. State Police P25 System) Along with the two trunks, Massachusetts State Police use several conventional frequencies, including the former low band channels. System ID: 0D14 P25 voice channels use N144 (Hex), 324 (Dec). Users should attempt to program the Simulcast sites for reception of most Talkgroups IntelliRepeaters are used for limited coverage/fill in of coverage sites and not all Talkgroups maybe heard. This page gets built by viewers like you. Please submit data and corrections.

Zone 15 Warwick IntelliRepeater Mount Grace, Warwick. (Franklin County) Licenses WPMG792

Franklin County Towns part of the FRCOG radio system. These TGs may be patched with their CoMIRS counterpart.

Backlinks: Software Heroes: Episode 1

Python tool to detect tones from an audio source and send notifications, by Andy Knitt. See more on the blog.

I wanted to see the code, looks like it's fundamentally just two python scripts. From version 70, it's based on Python 2.7. It's not open source, the author notes in the forum that he provided the source code at some point, and on the download site:

TwoToneDetect is free for personal and noncommercial use by public safety agencies and organizations. If you’d like to use the program for commercial purposes, please contact me.

Version 70 includes pushover but apparently that has been removed (since now IaR is paying the bills?). Since it's free for personal use, I wanted to see if I can adapt the scripts for my own use and just to learn about radio. It's possible as follows:

strings TwoToneDetect70 | grep -i python
looks like 2.7
git clone https://github.com/extremecoders-re/pyinstxtractor
~/.pyenv/versions/2.7.18/bin/python pyinstxtractor/pyinstxtractor.py TwoToneDetect70
~/.pyenv/versions/2.7.18/bin/pip install uncompyle6
cd TwoToneDetect70_extracted
~/.pyenv/versions/2.7.18/bin/uncompyle6 TwoToneDetect70.pyc > TwoToneDetect70.py
~/.pyenv/versions/2.7.18/bin/uncompyle6 out00-PYZ.pyz_extracted/TTD70.pyc > out00-PYZ.pyz_extracted/TTD70.py

If you look in the TwoToneDetect70_extracted folder, this software actually includes GNU Readline, so technically the source codes needs to be provided (and the software needs to be licensed under GPL). I won't go so far to push these scripts to github, but you can follow the above steps if you want.

Setup:

• XRDS -RF KMR400 SMA to N Cable 6ft, N-Male to SMA-Male Connector Low Loss Extension Cable 50 Ohm SMA Cable for 3G/4G/5G/LTE/ADS-B/Ham/GPS/WiFi/RF Radio to Antenna Use Purchased Dec 27 2024 for $15.99, amazon link
• 5.5dBi 1090/978 N-Type Female Antenna - 26-inch by ADSBexchange Purchased Dec 27 2024 for $44.95, amazon link
• FlightAware Band Pass Signal Filter, Dual 978-1090 MHz, Dec 27 2024
• FlightAware Pro Stick, with bandpass total is $77.78 USD, Dec 27 2024

Goals:

• Dashboard so I can see what's coming off the antennae
• Feed various online services for fun

Attic placement sounds like it generally works well, but outside is best. Maybe worth optimizing the antennae location once I have the software up and running to my liking.