Not everyone wants to take on a construction project as complex as CTR2. With that in mind, I’ve decided to offer complete, plug & play systems. I’ve assembled six pre-configured systems that include everything you need to deploy CTR2 in your station. I also have three user interface options to choose from depending on your needs. You can decide which combination works best for you. And don’t worry – the modular CTR2 design allows you to easily add options in the future as your needs change.

December 24, 2021

Due to the current disarray in the global supply chain the relays I use on the RJ45 Switch, Radio Antenna Switch Controller, and Antenna Switch Controller boards are back ordered up to six months. This means that I won’t be able to supply these boards for the time being. I’ve marked the systems below that are impacted by this phenomenon. I can supply System #1 and System #3 packages so you can start with a manually switched system and add auto switching functionality in the future when the switch board come available. I am sincerely sorry for this inconvenience.


The systems below come completely assembled, programmed, tested, and ready to deploy. Each system comes with a one-year parts & labor warranty. The HMI comes with a 16 GB SD card pre-configured and installed. You only need to connect the HMI to a 12 volt DC power source, connect the RADIO I/O modules (if used) to an RJ45 switch (manual or CTR2 RJ45 Switch, if used) with user supplied CAT5 cables, and wire the RADIO I/O modules to your radios. Schematics to do this are here.

Systems can be order from the Order Form. You can also contact me to request a quote for a custom configuration.


This is the most basic system. It includes the HMI and AUXILIARY OPTION #1 boards and allows you to control one radio with the built-in radio I/O circuitry on the OPTION #1 board. Just connect it to a 12 VDC power source and wire the terminal block to your radio’s audio, PTT, and key lines and your ready to go. Plug your PC into the micro-USB connector on the Teensy 4.1 board and start enjoying digital modes. No sound cards, audio coupling, or kludgy PTT circuits required!


SYSTEM #2 Not currently available

For those that have a single radio already have a remote antenna switch to manage multiple antennas, this system is for you. It includes the HMI and AUXILIARY OPTION #1 boards featured in SYSTEM #1 and includes a 4-port ANTENNA SWITCH CONTROLLER that controls your remote antenna switch. This system allows you to set different antenna configurations for each band so it automatically selects the correct antenna when you tune to a band. The antenna controller also allows you to select multiple antennas if you’re using phased arrays so you can say goodby to that messy diode matrix.


(required remote antenna switch not shown)


If you have multiple radios you’d like to control and only have one antenna, or already have an antenna management solution you like in place, this system might fit your needs. It includes the HMI and AUXILIARY OPTION #2 boards. The OPTION #2 board does not include a radio I/O circuit so you’ll need to add a RADIO I/O module for each radio. You’ll also need a manual RJ45 switch to route the radio I/O signals from the RADIO I/O module to the HMI. This system can easily be expanded to 16 radios by simply adding additional RADIO I/O modules and cascading manual RJ45 switches.

SYSTEM #3 SYSTEM #3 with required manual RJ45

switch and one RADIO I/O Module

SYSTEM #4 Not currently available

If you would rather have radio I/O signals automatically routed to the HMI when you select a radio (trust me, you will), this system is a better solution than SYSTEM #3. SYSTEM #4 comes with the HMI and the 4-port CTR2 RJ45 MASTER SWITCH. This switch replaces the AUXILIARY OPTION #2 board and manual RJ45 switch in SYSTEM #3. Simply plug the RADIO I/O modules into the switch using CAT5 cable and let the HMI do the work for you. You can easily expand the RJ45 switch in increments of 4, up to 16 ports, by adding additional 4-port RJ45 EXPANSION SWITCH boards to your system.

SYSTEM #4 SYSTEM #4 with one RADIO I/O Module

SYSTEM #5 Not currently available

If you like the idea of automatically routing radio I/O signals to the HMI when you select a radio, you’ll love having your antenna switched automatically to the selected radio too. This system adds the 4-port RADIO ANTENNA SWITCH CONTROLLER (RASC) board to the SYSTEM #4 equipment list. This board controls a user supplied remote antenna switch to route the common antenna port to the selected radio. With this option, just select the radio you want and CTR2 does the rest. This system requires a RADIO I/O module for each of your radios.

SYSTEM #5 SYSTEM #5 with one RADIO I/O Module

SYSTEM #6 Not currently available

If you have multiple radios and antennas this system was designed for you. It adds the 4-port ANTENNA SWITCH CONTROLLER (ASC) board to the SYSTEM #5 equipment list. With SYSTEM #6 your radio’s I/O, radio antenna port, and antenna are automatically routed for you when you select a radio. Remote antenna switches are required for both the RASC and ASC. The ANTENNA SWITCH CONTROLLER also allows you to select specific antennas for each band and each radio. The system can easily be expanded to control up to 16 radios and 8 antennas.

SYSTEM #6 SYSTEM #6 with one RADIO I/O Module


The systems above do not include the user interface because each user has a different need. Some want a dedicated control console independent of the station PC and the Internet. Others want to control their stations using their station PC or from a remote location.. be it just upstairs or from across the country.


If you want a small dedicated console to control your station, this may fit the bill. It incorporates the Nextion 3.5″ color touchscreen display mounted in a wedge shaped enclosure that sits comfortably next to your key or keyboard. It includes a rotary encoder so frequency and parameter changes are close at hand, no matter which radio you’re operating. The display is small but bright and easy to read. Touch controls are best selected with the side edge of your fingernail or with a scribe.

USER INTERFACE #1 – 3.5″ Display


If you want a little larger dedicated console, this option is better suited for you. It incorporates the Nextion 5″ color touchscreen display, again mounted in a slightly larger wedge shaped enclosure that still sits comfortably next to your key or keyboard. It too includes a rotary encoder for frequency and parameter control. The display is larger but the viewing angle and colors are not quite as good as the 3.5″ display. The larger text and touch controls make up the difference though. You can easily operate this console without a scribe or reading glasses 🙂

USER INTERFACE #2 – 5″ Display


If you would rather operate CTR2 from a browser on you PC or smartphone, this is your option. Using Node-RED I’ve been able to recreate most of the dedicated console features in a web-enabled environment. This means that you can operate and control your station from anywhere from any device that features a modern browser. It also offers a few more features not available on the dedicated consoles like one button QRZ look ups and one button access to Reverse Beacon Network and PSKReporter maps.

One of the big advantages of this option is that it is nearly free. Node-RED can be installed on nearly any PC on the planet that runs Windows, Mac OS, IOS, or Linux. I’ve found that an old Raspberry Pi 3 has more than enough horsepower to run the system and support the SonoBus audio interface. On the Raspberry you can connect the Local Display I/O on the HMI directly to the Raspberry’s GPIO bus since they’re both 3.3 volt based. If you use another PC you’ll need an RS232 to 3.3V TTL adapter to connect to the HMI. Either way, this is a cheap way to go. I recommend trying it before investing in a dedicated controller.


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