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  • Elmer

Hello all!

I just found this topic and thought, why not? I'm not usually one to pound my own drum and I've never liked being the focus of attention, but I thought there might be some interest out there in what I've been doing lately.

I call the project I've been working on 'CTR2-Mini', short for 'Control the Radio too - Miniature' and you can read a little about it in this months' QST (Sept. 2022). It's a much simpler take-off of a larger system I built last year called 'CTR2'. That project was published in the Sept/Oct 2021 and Jan/Feb 2022 issues of QEX. CTR2 was a pretty complicated system that allowed you to select up to 16 different radios and control them from a small display or a Node-RED flow. Unfortunately the global supply chain issues killed the project as many of the components I used on it are still unavailable.

I redesigned CTR2-Mini to be much simpler, easier to build, and a lot cheaper.

Here's a few photos of the unit.  The first shows the right-hand version. I can supply a left handed enclosure if that works better for you. The second photo is the small Radio I/O interface that connects the Mini to your radio. For size reference those are 1/8" phone jacks and a CAT5 connector on the board. The third photo shows two Minis in a dual enclosure with their Radio I/O units. The last photo shows two Minis operating an FTdx101 in Dual VFO control mode. The Mini on the left is controlling the Main VFO and the one on the right is controlling the the Sub VFO. Only one CAT connection to the radio is required. The Minis can be located anywhere in your shack (I like them just in back of my keyboard) so I can easily change radio settings. The Mini works with many other radios including FlexRadios where you can have one Mini controlling each slice in the radio. Of course the Mini includes a contest keyer too.

You can read more about the Mini in my blog, https://ctr2.lynovation.com  I also have a YouTube channel, https://youtube.com/lynovation where I demonstrate the various features of the system.

I can supply PCBs with the SMT components pre-installed for all the boards in this project. I can also supply assembled acrylic stands as shown in the photos. I have project lists on Mouser that allow you order all the through-hole parts and the Wio Terminal to build the project with just a couple of clicks. I can also supply custom built, complete, tested, ready to use systems if you don't want to build your own.

In addition to the Mini I'm working on a companion antenna switch controller that can control single and dual port antenna switches and an SO2R controller that shares mics, headphones, paddles, function buttons, and a remote PTT switch between two Minis and their radios. The information on those options is also on my blog.

Let me know if you have any questions,

73, Lynn, KU7Q





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  • Administrator

Hi Lynn. I will ‘see’ your posting and ‘raise you’ by promoting the post to our Picks section on the home page. Also, don’t forget to post your youtube channel in our Youtube channel section here: https://hamcommunity.com/links/category/21-youtube-channels/ and your blog here: https://hamcommunity.com/links/category/20-individual-blogs/



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  • 1 month later...
  • Elmer

The Mini firmware includes several options to link two Mini's together. One of them is Remote Controller. Mini's that are linked are identified as Mini-A (server) and Mini-B (client). In Remote Controller link mode, Mini-B resides in your station and is connected directly to and controlling your radio. It is also connected to your LAN via WiFi. Mini-A connects to Mini-B over the IP network. Mini-A can be just about anywhere if you forward Mini-B's IP port through your router. Mini-A can also control the CTR2-Mini Antenna Switch Controller (ASC) remotely. You just need to forward the ASC's IP port through your router too. This gives you remote control for any radio the Mini can control.

If you have a Flex 6xxx radio a single Mini can connect to and control it over the internet without SmartSDR running.

In Remote Controller (and Flex control) you can remotely control PTT on the local radio. I currently don't support direct CW keying from Mini-A to Mini-B in Remote Controller link mode. but do support it when connected to the Flex radio. You'll need an audio server like Mumble or SonoBus to pass your radio's audio to and from your remote location. A cell phone or tablet works great for this.

The Mini doesn't support all options on every radio. By design I limit the CAT control to the basics like frequency and mode. There are expanded options for some radios such as the Flex, PCR-1000, and FTdx radios and I'm working on adding Kenwood to that list. The Mini doesn't provide the immersive remote control experience you can get with PC to PC systems or the dedicated remote control systems, but it works good for simple control such as when you just want to run the radio in the basement from your deck or family room. You can find more information on CTR2-Mini on my blog, https://ctr2.lynovation.com.

73, Lynn, KU7Q



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  • 5 months later...
  • Elmer

This post was recognized by K3MRI!

"A great content award is well deserved for this thread and the most recent post. Thanks Lynn."

KU7Q was awarded the badge 'Great Content' and 2 points.

I just wanted to update this topic with some of the recent improvements and additions to the CTR2-Mini ecosystem.

First, I've updated the Mini to the Mini+. It has all the features of the Mini shown in prior posts and includes a built-in function keypad, a better sidetone amp w/volume control, a built-in 12VDC power supply (no need to plug the Wio Terminal into a USB port to power the Mini), and a built-in radio I/O circuit allowing the Mini+ to connect directly to one radio without any external modules. Here's  photo of the new Mini+ and a diagram showing it connected to a single radio...


I've developed additional hardware to expand the basic Mini control system. The new CTR2-Mini I/O Multiplexer replaces the manual RJ45 CAT5 switch that was used to select from multiple radios. It automatically routes the radio I/O from the Mini+ to the selected radio. The multiplexer also has an antenna switch control port that can connect  to a remote antenna switch to route the antenna to the selected radio too. You can easily add up to three more multiplexers and 4-port antenna switches to expand the system and control up to 16 radios with one Mini+.



A new CTR2-Mini Audio Controller will be available in March 2023. This unit that sits between the Mini+ and the Multiplexer and couples Line-In and Line-Out audio into the I/O circuit. Its function is to allow you to use the same mic (select from two) and headset with all of your radios. It also brings out the selected radio's audio that you can connect to a USB audio card allowing you to share your sound card with all of your radios.



Finally, the SO2R controller I introduced earlier is nearing completion. It allows you to connect to and control two radios, each with its own Mini+ controller for full SO2R operation. The Mini's can be linked together to provide synchronous frequency operation (for full diversity reception) or split synchronized frequency control where the radios are locked together but tuning separate bands. You can listen to each receiver in different headphone speakers, combine them into one mono audio stream, or just listen to either radio in full mono (both headphone speakers). PTT/Key and Line-Out audio are automatically routed to the selected radio.


The firmware has also been vastly expanded since last summer. I now support most of the major radios. Support for Flex radios has also been enhanced and now features GUI and non-GUI control modes (with a small panadapter available in GUI mode). You can connect to the CAT port on your radio via serial or through the network via a TCP/IP port. Hamlib rigctld is also supported. Each radio has its own dashboard where the common commands and features are visible and accessible. I've also enhanced the function keypad. You can pick from up to 38 functions that can be assigned to normal or shifted function keys. Many of the common settings on your radio can be assigned to a function buttons for instant access to that setting.

I've added a couple of special modes users have asked for.

The first is Meter mode. In this mode the Mini+ acts as a dedicated multi-function meter for your radio displaying S, Power, SWR, ALC, and Compression all the time. Just turn the encoder to return to the Home page to tune your radio or do other housekeeping. Once you're done the Mini+ returns to Meter mode.


The second new mode is the External Tuner mode. Use this mode when you have an external antenna turner. When you enter this mode the Mini+ automatically sets your radio to CW and reduces power to a setting you choose. Simply press the Key or PTT button to key the radio to tune your tuner. When your done, exit External Tuner mode and the Mini+ restores your radio back to the normal operating mode.


I've also added a few other things like Code Practice mode for those wanting to upgrade their code skills and a new Previous Frequency menu that allows you to jump back to the last 13 frequencies you have visited.

You can find out more about these new features on my blog at https://ctr2.lynovation.com/ctr2-mini-modular-system

73, Lynn, KU7Q

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