KC908 Spectrometer Firmware Update Manual & Download

          KC908 supports updating its firmware through TF card (AKA card flash) as well as through USB(Not supported currently). In this article, the TF card updating procedure would be covered. At the end of this page there would be firmwares to be downloaded, which would be updated aperiodically.

          Note that KC908 does not verify the version of the firmware, thus users can flash a newer firmware as well as an older one.


               (1) KC908, with a battery voltage above 7V, battery supply only.

               (2) TF card, within 32GB, FAT32 file system.

               (3) A card reader and a computer.

         2. Place the firmware (sdr_908.kc) at the root of the TF card.

         3.  Insert the TF card into the left TF slot of KC908, make sure the metal  contact point towards upper side.

         4. Press POWER button to boot KC908 and wait until the booting completes.

         5.  Press FUNC button to enter the menu.

         6.  Navigate the cursor to “system update”using knobs or “+”,“-”button and press ENTER. Or user can directly choose “system update”option on the on-screen menu.

     If the system fails to read the TF card, the right side of the screen would display the message to notify the user. (As shown in the pic below). Those factors contributing to this situation could be TF card incorrect insertion, poor contact, file system error, or maybe the file itself is corrupted, which means the file name is incorrect, or the file itself is not KC908’s firmware in the first place. User can sort out the reason accordingly. Exit this system update menu and re-enter it to refresh the display.

     With TF card being read successfully, the update version would be displayed on the right side on the screen.


        7.  Check the info and press “update”option, KC908 would ask for confirmation again. Press the OK button to start updating.

       It would take a relatively long period to update. This period varies from half a minute or longer depending on the firmware’s version. Please be patient in this process.

      8. When the update completes, the process bar shows 100%. The on-screen menu offers options, press the button to reboot KC908.

      During the reboot progress, the classical updating blue screen appears.

      9. In cases where rare anomalies during update brick KC908, or where KC908 gets stuck at booting screen or lose response after booting due to fatal error inside the system, and cannot enter the update menu utilizing the normal procedure mention above, the legacy update method of KC could be helpful.

      Execute step 1-3 exactly the same. There are 5 menu buttons on the first row on the keyboard, press those 3 starting from right and hold them, press RST button once while keeping those 3 menu buttons pressed until KC908 boots. From this moment on, KC908 would commit firmware updating automatically. If the machine remains irresponsive after 3 min, it means no firmware is found in the TF card. Please make sure the firmware file is correctly place in the TF card and try again. If multiple times of failure happen, please contact your retailer.

Attention: Despite the fact that it’s possible to read/write the TF card after connecting KC908 to the computer using a USB cable, KC908 would not be able to access the file in the TF card correctly since the TF card is occupied by the USB. DO NOT connect KC908 to a computer while updating. One more thing, KC908 cannot completely reset itself by rebooting while it’s being supplied power externally. Since that, please disconnect the charging cable before rebooting.

Firmware Download

V1.0.3, 2020.4.28. Approximately 13MB. Repair: Logical errors at spectrometer interface which freeze the system when the initial frequency goes across 0, or when peak table function is activated. Update: Several details in functions.

V1.0.4, 2020.4.30. Approximately 13MB. Mainly improve residual response, repair the problem that signal source function may fail to start. As well as improving the success rate of USB charging.

V1.0.5, 2020.5.8. Approximately 15.7MB. This version adds a function to enable remote control as well as high speed IQ data access through USB3.0. Fix recent accumulative flaws.

V1.0.6, 2020.5.19. Approximately 15.6MB. This version mainly fixes recent problems like SHIFT key cannot be hold for seconds, ALC oscillation. Also, LEV TONE performance improved. Fluency of large demodulation bandwidth optimized. Freezing happening rate reduced.





Due to the fact that the settings of preamplifiers directly affect the anti-interference ability, they should be set manually to improve flexibility under complicated electro-magnetic environment. For this reason, preamplifiers does not get involved in auto adjustment anymore. The objects of ALC adjustment would be restricted within ATT and IF GAIN. By default the PRE AMP is set to 20dB, which is a recommended value. In relatively ideal electro-magnetic environment like rural areas, or while using a small pull rod antenna to receive short-wave frequency band, this value can be set to 40dB.

V1.0.7, 2020.6.2. Approximately 39.4MB. This version introduces functions of RF components’ self-diagnosis as well as the auto-calibration of the signal source. Also, support for large volume TF card with exfat file system is introduced. (Only available to a minority of TF cards, and the max volume remains to be 32GB to ensure reliability). Single-sideband demodulation performance under large bandwidth improved. Bugs fixed.

V1.0.8, 2020.6.3, approximately 39.4MB. Fix the problem that some settings in signal source mode would cause freezing in firmware 1.0.7. The RF components’ self-diagnosis function in 1.0.7 and 1.0.8 are both experimental and thus some parameters are relatively more restricted. False alarm could possibly appear. Just for information.

V1.0.9, fix the problem that there are errors in the content while storing the IQ file.

V1.1.0, 2020.6.29, approximately 42.1MB. Spectrometer mode introduces zero sweeping bandwidth function.

 V1.2.0, 2020.7.24, approximately 42.1MB. This version adds the function of comparator as well as offers option for adding additve info on screenshots (however what info to add remains uncertain). Moreover, this firmware allows the user to switch off the band pitch function of VFO.

Fix the problem of causing other mode to freeze while switching from signal source mode. Optimize the calculating method of RBW, displaying RBW with 3db bandwidth. Fix the problem of upper and lower sidebands flip in SSB demodulation below 1GHz. Optimize operation procedure of peak list in receiver mode. Other dozens of fixes and optimizations in this firmware improve stability and usability.

Problems Remained: Possibility of measured data become mistaken or unable to refresh while switching to other modes from signal source mode, which would require a complete reboot to return to normal.

Comparator is an experimental function, which means it would probably be buggy.

Update Recommendation: We recommend all beta test user this version of firmware. Other users can stay at their current version if they feel comfortable with it.

Download v1.2.0

V1.3.0 20200821

This version fixes several bugs, optimizes the peak list function, and adds a marker demodulation function for the receiver that can be demodulated anywhere in the receiver spectrum.

Note: The frequency step of the marker demodulation function depends on the step and is not suitable for use at large frequency spans (SPAN). If you need to precisely specify the frequency of the marker demodulation, you can enter the frequency using the keyboard after entering the Marker menu.

V1.4.0 20200910

Improve support for GNURadio (see manual at PDF). Add keyboard shortcut shift+. for switching frequency band. Fix the problem that the trigger channel of the comparator does not correspond to the actual display channel, improve the frequency accuracy of cursor demodulation, and fix some UI bugs.

v1.4.1 20200911

This version optimizes the LEV TONE function for a finer and more comfortable representation of level changes. Implemented the ability to enter the FUNC interface while the receiver is operating, and receive demodulation continues and is no longer paused (except for conflicting secondary setup items). Fixes anomalies in RF source modulation.

Download 1.4.1

Download GNURadio files

Please pay attention that the indications from the charging indicator differ from the original user manual form firmware version 1.0.3.

They have been modified to be:


Red Light: 12V port charging, USB 5V port slowly charging.

Blue Light: USB port quickly charging.

Green Light: Fully charge.