I have been a fan of the firmware modified Quansheng UV-K5 handhelds for a while now. The base radio is not bad and the features added by Hams through firmware modifications have been very useful. The radio is available through the usual sources including AliExpress, Amazon, Ebay, etc. The radio is known as the Quansheng UV-K5, UV-K6, and UV-K5(99). It’s also sold as the Retevis RA79 and as the Xindalong UV-K5(9). There are likely other names for this radio.
Modified firmware is flashed onto the radio using a standard Kenwood style USB programming cable using a firmware flashing application that uses the Web Serial API on the Chrome Browser. To put the radio into firmware update mode, you press the PTT button while turning on the radio.
Egzumer
The egzumer firmware provides a calibrated S-meter in Decibels and a spectrum analyzer and other nifty features. Once you flash the radio with upgraded firmware, there are updated instructions needed to operate the radio. If you use the popular programming software, Chirp, there is now an updated driver for the modified firmware included in the Chirp software.
Full Band Receive Modification
I recently installed a popular full HF band hardware and firmware modification to one of my UV-K5 radios. Paul, OM0ET has created an excellent YouTube video of how to do that. The modification circuit board contains a Skyworks Si4732 IC that replaces the 8pin DIP BK1080 FM Broadcast Receiver IC. Note, this modification does not replace the primary transceiver IC.
While watching Paul’s video, I thought it was going to be fairly easy to do the modification, so I ordered two of the new Si4732 boards. The clarity of his images of the circuit board were excellent. When my boards arrived and I got around to installing one in a radio, it was more complicated than I thought!
It was hard for me to see the places where you interconnect the modification board with the main circuit board of the UV-K5. I could have used much better magnification. Using Paul’s excellent video and tips on how to install the board and antenna, I was able to get the job done and it works!
I installed the board and SMA jack and then reset the microprocessor. I am able to receive the HF bands very well now.
Version 3.0 expanded RX with Bluetooth
There’s another board available that provides the SI4732 chip; it also includes Bluetooth support.
Desktop UV-K5
Paul, OM0ET has also built a beautiful desktop radio out of a Quansheng UV-K5 that includes a rotary encoder for tuning! Hackaday did a nice write-up on that with links to Paul’s YouTube video about it.
UV-K5 Reverse Engineering Project
There is information available about the inner workings of the UV-K5 radio that may be helpful when thinking about modifications.
Running FT8 on the UV-K5
I guess it shouldn’t amaze me that someone has figured out how to run FT8 through WSJT-X on the UV-K5!
IU0IJV Modifications
Fabrizio, IU0IJV has created several popular firmware updates for the Quansheng UV-K5 and its variants. An extensive manual is available for the different versions.
Hackaday
The Hackaday site has some great information about the Quansheng UV-K5 radios.
off-grid Messaging
Youtuber “sn0ren” has a very interesting video about yet another version of the firmware based on the egzumer firmware that includes off-grid messaging!
3cm Transverter for UV-K5
Fred, OE8FNK has developed a prototype for a 3cm (10 GHz) transverter for the UV-K5
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