Are you ready to share your ham knowledge?

Great! CATS is a cutting edge portal into the newest ham radio technologies.

DX and Antennas

Chasing DX is fun but you need the right and antenna and tips from fellow hams when it's active.

Digital Radio

Whether it's DMR, DStar, Fusion, or P25, we're there. We also sponsor many local repeaters.


Stay up to date with the latest weather alerts and help the NWS with Chicagoland Skywarn.

Pi & SDR

Learn all about what a simple microcomputer like the Raspberry Pi can do. Arduinos are fun too.

About Us

The Chicagoland Amateur Technical Society (CATS) is a group of inquisitive minds that share their technical knowledge and collaborate on hands-on projects. While we embrace the traditional amateur radio activities of chasing rare DX, contesting, or communicating on repeaters, we focus on new digital radio technologies. We share antenna designs and tips from years of experience. We dive into microcomputers and software defined radio projects. We support Skywarn in our area. We believe in the confluence of radios, computers, and the internet.

Next Meeting

December XX, 20XX


Julio's Tacos

We will discuss technical stuff and drink

Useful Software

Fun stuff to keep you busy as the weather gets colder.


Solar Conditions


Solar Conditions






What do all these numbers mean?
Future Ducting Forecasts

Local Hangout Frequencies and Connection Information

This affiliated system is accessible via local RF repeaters below,
DStar DCS312B/REF312B, Fusion FCS08623 and Room 40911 (TriStateDMR), Allstar #45417, Echolink AA9VI-R #7641
Location Callsign Frequency (MHz) Offset (MHz) Color Code Timeslot Talkgroup
Bolingbrook, IL K9BAR 443.7 + 5.0 1 1 8
Chicago, IL AA9VI 441.21875 + 5.0 1 1 8
Crown Point, IN N9IAA 444.35 + 5.0 1 1 8
Crystal Lake, IL K9VI 444.80625 + 5.0 4 1 8
Inverness, IL K9ORD 441.05 + 5.0 1 1 8
LaPorte, IN N9IAA 444.675 + 5.0 1 1 8
Schaumburg, IL K9MOT 444.80625 + 5.0 1 1 8
Valparaiso, IN N9IAA 441.21875 + 5.0 1 1 8

We also operate two small coverage (10-15mi) digital MMDVM repeaters and a simplex Allstar node. Various nets are active throughout the week.
Location Callsign Frequency (MHz) Offset (MHz) Access Description
Inverness, IL K9ORD__C 147.39 + 0.6   DStar, Fusion
Inverness, IL K9ORD__B 441.05 + 5.0 CC1, NAC293 DStar, Fusion, DMR, P25
Inverness, IL K9ORD 445.55   114.8 Hz Allstarlink #42060

The P25 Midwest Bridge is not directly affiliated but is recommended.
System Status
Location Callsign Frequency (MHz) Offset (MHz) NAC Talkgroup
Joliet, IL K9FRG 442.95 + 5.0 293 10
McHenry, IL KB9I 444.075 + 5.0 057 10
Round Lake Beach, IL N9JSF 443.775 +5.0 057 10
Schaumburg, IL K9FRG 442.9 + 5.0 293 10

146.58 MHz simplex analog is a great place to be for informal ragchewing.

Not affiliated but suggested.
Location Callsign Frequency (MHz) Offset (MHz) Dig-ID Room
Northbrook, IL NS9RC 147.345 + 5.0 00 Minn.-Wisc.
Lisle, IL WA9WSL 442.225 + 5.0 00  
Michigan City, IN W9LY 441.950 + 5.0 00  


Maps, warnings, and other local information on our partner site

Join our Email Group to Learn More!

Find out what we're doing and how you can share your ham knowledge.