CTR2-Max-5

August 13, 2026

Several weeks ago, I opened CTR2-Max ordering up to the CTR2 IO group to give them the first opportunity to own a new CTR2-Max. The overwhelming response has created a backlog of orders that I’m still working through. Once these orders are shipped (hopefully by the end of August), I’ll open up ordering here. 

Thanks for your patience!

CTR2-Max-5 (Max) is the latest addition to the CTR2 controller family. It has the same functionality as CTR2-Quad in that it supports Bluetooth and USB MIDI control that works with many radio control apps like SmartSDR for iOS/MacOS, AetherSDR, RimuSDR, OnlineRemoteRadio, and RemoteTx. It also supports direct Flex radio control over Wifi using the Flex network API.

In addition, it features a much larger touchscreen display (2.8″ compared to 1.28″ on the Quad), one additional knob, and two additional buttons.

Normally, in Flex WiFi mode, Max connects to your radio as a non-GUI client. In this mode, Max runs in parallel to the main GUI client connected to the radio (i.e. SmartSDR for Windows, or iOS/MacOS, AetherSDR, RimuSDR, etc),  A new feature has been add to Max that allows you to connect to your radio as a GUI client, without another client connected. In this mode, a mini-panadapter is displayed (see the lead photo).

Unlike previous CTR2 controllers which use a piezo buzzer for sidetone (when operating in direct Flex control mode), Max produces a true sinusoidal sidetone with full pitch and level control. The output of the codec feeds a 1.2 watt amplifier that drives a real speaker. Not only is the sidetone easier to listen to, an optional sidetone audio interface option allows you to patch the transformer-isolated sidetone from Max to your headphones, powered speaker, mixer, or PC sound card. See the limitations of this option below.

Max is also designed to support up to a 2000 mAH internal Lipo battery. Two battery input connectors allow for different battery connector polarities. A battery isolation switch totally disconnects the battery when not in use to preserve its charge. A 2000 mAH battery will power the unit for up to 12 hours. You can enable a battery icon to monitor the charging/discharging state of your battery.

NOTE: Due to shipping restrictions, the user must supply and install the battery. They are readily available at Amazon and other online retailers.

This unit is heavier than other CTR2 controllers. For domestic orders, the flat rate fee will cover the additional weight. For international orders, there is a USD 20 shipping fee in addition to the flat shipping rate.

ORDERS SHIPPING TO GERMANY

USPS now requires that I collect duties and tariff fees up front, instead of you paying them on delivery. This fee is calculated when I create the shipping documents, do I can’t create a line item for it on this order form. I’ll send you a separate PayPal invoice for these fees when I process your order. I’m sorry for the inconvenience this will cause (to both of us!).

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Please enter your call sign in the Add a note to your order section on the Checkout page so I can create your registration key.

Failure to do so may delay your order.

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