For a free computer-aided transceiver (CAT) control foundation, start by checking Hamlib’s supported-radio list. Hamlib and its rigctld service are the strongest general-purpose options in the available evidence; FLRig may fit when your other software supports it. Gqrx is aimed at software-defined radio (SDR) receiver use, not established as a general transceiver-control replacement. No authoritative CatRadio documentation was identified, so a feature-for-feature replacement cannot be named: verify your radio, operating system, target application and required CAT functions before choosing.
What “free CAT control software” can mean
These options do different jobs. A control library can let compatible applications talk to a radio; a daemon can share that control interface over a network connection; a graphical rig-control application may provide an operator-facing workflow; and an SDR receiver’s remote-control feature may apply only to that receiver. Treating them as interchangeable can lead to choosing software that does not perform the task you need.
As an Amazon Associate I earn from qualifying purchases.
- Hamlib provides a common radio-control interface. Its rigctld daemon accepts client requests through TCP sockets, which can be useful when compatible programs need a shared control service.
- FLRig appears in Hamlib’s supported-radio listing as a backend. The evidence here does not establish particular GUI features or operating-system support, so check the FLRig version and instructions for your own setup.
- Gqrx is an open-source SDR receiver with basic TCP remote control, according to the Gqrx project. That description does not make it a general-purpose CAT controller for conventional transceivers.
Hamlib’s FAQ says, “Hamlib has a solution for this, it is called rigctld.” The project advises users whose applications use Hamlib to follow those applications’ own setup directions and seek support from their providers.
Recommended Free Tools
Which option fits your setup?
| Option | Best fit | Boundary to understand | Check before choosing |
|---|---|---|---|
| Hamlib with rigctl or rigctld | Radio control through a common interface; rigctld can serve compatible clients over TCP. | Support depends on the exact radio model and implemented commands. rigctld is a daemon, not necessarily a standalone graphical control panel. | Model and support status; whether your application supports Hamlib or rigctld; whether it implements the commands you need. |
| FLRig | A possible rig-control application/backend when your other software supports it. | Hamlib lists FLRig as a backend, but the available evidence does not establish specific GUI features or platform support. | Application version, integration with the target program, and radio-specific setup instructions. |
| Gqrx | An SDR receiver workflow where basic remote control is useful. | It is described as an SDR receiver, not as a general transceiver CAT-control substitute. | SDR hardware and software requirements, and whether its remote-control functions cover your task. |
| Elecraft control/setup programs | Owners of specific Elecraft radios covered by the manufacturer’s downloads. | Elecraft describes its downloads as a free service to customers and provided as-is; model coverage is limited to equipment listed by the manufacturer. | Whether your exact K3, KX3 or K2-family radio and desired function are covered. |
| Ham Radio Deluxe | Operators considering a more integrated paid option. | The vendor offers a free 30-day trial and describes Rig Control as licensed software; it is not an ongoing free alternative. | Current license terms, required functions and radio support. |
There is not enough evidence for a complete, like-for-like feature matrix across these choices. Compare the specific tasks you need—such as reading frequency, changing mode or controlling PTT—instead of relying on a universal ranking.
#1 Best Overall
- Mini mobile two way radio; 1.54"D x 4.88"W x 6.42"H; easy to install on trucks; jeeps; RVs and other vehicles; use the RT95 as a base station at home or in the office; long range communication; RT95 ham radio with high gain antenna; to obtain long distance signal sources; communication is more convenient
- Microphone gain & dual speakers; adjust the microphone gain level appropriately to ensure clear and interference-free calls; with the built-in dual speaker design; the sound quality is full and penetrating; equipped with RCA output ports; can be directly connected to car audio systems; immersive in-car listening experience
- 180 degree rotatable TFT color screen; free adjustment of viewing angle; supports multi-level control of LCD brightness; clearly visible under strong light; no glare during night operation; illuminated front panel buttons and microphone buttons; clear operation buttons at night; suitable for all-weather use scenarios
- Dual band mobile transceiver; amateur radio display the dual frequencies; and monitor dual band signals (2m/70cm band) at the same time; quickly respond to key communication needs; and improve work efficiency and safety
- VFO fast frequency adjustment & CHIRP compatible; VFO mode supports instant frequency adjustment; no computer is required for outdoor travel; compatible with CHIRP open source software; one-click import/export of channel parameters; easy management of 200 storage channels; CTCSS/DCS; DTMF; 5Tone; power adjustment; etc
How to check whether Hamlib supports your radio
- Find the exact model in the Hamlib supported-radio listing. Do not assume that a family name or a similar model is equivalent.
- Read the listed support status. Entries may be marked stable, beta, alpha or untested. A listing confirms an entry and status, not that every function you need works.
- Check your target application’s documentation. Confirm whether it supports Hamlib, rigctl, rigctld or another connection method, and follow that application’s setup instructions.
- Match the supported commands to your use. Confirm that the application and radio combination covers the controls you need, such as frequency, mode or PTT. The model listing alone does not guarantee each command.
Plan the radio-to-computer connection
Start with the transceiver’s manual: manufacturers use different CAT protocols and settings. The Ham Radio Deluxe rig-control guidance also describes selecting a radio and COM port, but its setup guidance does not establish universal values for other radios or programs.
- Identify whether the radio exposes a virtual COM port over USB or needs a physical serial connection or USB-to-serial adapter.
- Check the radio’s connector, CAT protocol, driver, baud rate and other serial parameters against its manual and the software’s instructions.
- Use the correct device or COM port in the control application. Port names and available drivers depend on the radio, computer and operating system.
- Buy an interface only if your radio and computer require one. Match the cable or adapter to the exact radio connector, protocol and driver needs; a generic USB cable is not guaranteed to support CAT control.
The connection details are radio-specific; no single baud rate, cable or set of serial parameters applies to all radios.
Rank #2
- 100W (25W AM) Output power
- 0.030-74.800 RX frequencies
- Receiver type: Direct sampling
When multiple applications need radio control
If several programs need access, check whether they can use a shared-control arrangement rather than each trying to open the radio’s serial port directly. Hamlib documents rigctld as a TCP socket daemon, and its FAQ identifies it as a way to provide a shared control service. Your applications must support the relevant client connection, and their setup instructions still apply; compatibility is not guaranteed for every operating-system or application combination.
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Troubleshoot a CAT connection that will not open
- Confirm the radio-side CAT setting and connection mode in the transceiver manual.
- Check the selected port against the device shown by your operating system, and confirm that the required driver is installed.
- Verify serial settings such as baud rate and other parameters against the radio and application documentation.
- Check for a port conflict. Another program may already be using a serial port that cannot be shared directly; investigate a supported rigctld arrangement if the applications allow it.
- Ask the right support source. For software that uses Hamlib, the project FAQ directs ordinary users to the application provider’s setup instructions and support.
Can any of these be called a CatRadio replacement?
Not responsibly on the evidence available here. An authoritative CatRadio product page or manual was not identified, so its supported radios, features, platforms and license cannot be verified or compared. Choose by your own requirements and the alternatives’ documented compatibility rather than assuming feature parity.
Rank #3
- MENUS THAT MAKE SENSE. 1,000 MEMORIES. 10 NAMED ZONES. Built for amateur operators who want organized analog control. Use clear English menus and the full keypad for common changes; group home, travel, club, event, simplex, and receive channels as your plan grows.
- SCAN THE ZONES THAT MATTER. Choose which named zones scan together. Temporarily skip a busy channel without changing your saved scan list. Scanning is for conventional analog channels; it does not decode DMR/digital or trunked systems.
- MORE INFORMATION AT A GLANCE. Choose Name + Frequency in the two-channel view. Dual Watch alternates one receiver between the two displayed channels. Turn Dual Watch off and enable Single Watch for a full-screen view of one channel's name, zone, and frequency. Approximate dBm adds signal context.
- START ON THE RADIO. BUILD LARGER PLANS ON A COMPUTER. Make common changes from the keypad. For larger plans, use BTECH CPS or supported CHIRP-next with the separately sold PC03. Firmware updates require BTECH CPS, the PC03, and BTECH's matching instructions. USB-C charges the battery.
- TRI-BAND AMATEUR TRANSMIT. RECEIVE-ONLY LISTENING. Valid amateur authorization is required to transmit on amateur frequencies in the U.S.; use only supported amateur bands within your privileges. Airband AM, NOAA weather, and broadcast FM are receive-only.
A community discussion asks, “What are the current alternatives to HRD today?” That captures a common kind of comparison question, but it is not a product specification or evidence of what CatRadio supports.
Quick Recap
Best Value
- Detachable Display Unit - The display unit and the radio body can be separated. This allows you to place the head remotely. FCC ID: 2BGMW-G90
- Wide Range Auto Antenna Tuner - Unlike other QRP radios, the G90 has a wide-range internal automatic antenna tuner so you can load up your favorite field antenna! The G90 also comes with a built-in mediumwave (AM broadcast) high-pass filter.
- Beautiful Color LCD Screen - All vital operating information is clearly visible in daylight conditions. 48KHZ wide spectrum display with waterfall gives you excellent awareness of the signal conditions around you.
- Easy to Use - You can use the Quick Mode button to turn on or off various functions. Instead of setting up different functions in the menu, you can directly adjust them by pressing corresponding function keys.
- We provide a 18 months warranty on Xiegu G90. As usual, if you modify the radio's hardware, the warranty is void. [Latest Firmware Version] - Firmware V1.81 is available on Radioddity official.
Rank #4
- Quad-Band Operation: The TH-9800D mobile radio frequency range: TX: 28-29.7 / 50-54 / 144-148 / 420-450 MHz, suitable for various communication scenarios. If you encounter any programming issues, please feel free to contact us via Amazon Message
- Dual Display & Cross-Band Repeat: The mobile ham radio display 2 frequencies simultaneously, supports cross segment relay function, enhances communication flexibility and coverage range
- High Power & Adjustable Output: Ham mobile transceiver delivers up to 50W output with multiple power settings (High/Mid/Low) for flexible operation
- Detachable Control Head: TH-9800D radio remote-mount faceplate for easy installation in vehicles; stores up to 800 alphanumeric memory channels
- Includes Programming Cable & Software: The radios comes with programming cable and software (also compatible with free CHIRP software) for convenient and efficient
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
