Downloads for the Q900
The download section of the Guohetec website is not always up to date. I will try to provide some files that are not available on their site including some older versions known to be working well.
Please check the download section from Guohetec first for available downloads.
There should be a USB drive included in the package with the Q900. You will find the manual and additional software in the newest versions at the time of production.
Download and use the files from this website at your own risk!
Firmware
Update 2024/01/18:
Firmware 3.4.6 has been released a few days ago. No known changelog.
First testing gave me the impression that they tried to work on the SSB modulation, but the problems are still there.
Update 2023/12/29:
Firmware 3.4.5 has been released.
No known boot problems with this version so far.
Update 2023/12/25:
Firmware 3.4.4 has been released a few days ago.
Only a few devices had problems after the update including mine but I can’t recognize a general problem with this version.
But I can say that low power distortion and NMF bad modulation are not solved. for details check my video that I posted on my TX Audio site.
If you programmed chanels, save them with the software as a file, because they will be gone after the update. If you decide to got back to the old firmware, the chanels will be back.
Update 2023/11/05:
Firmware 3.4.3 has been released. You can get it on the Guohetec website for Q900, PMR-171 and TBR-119.
download section
!!! Update 2023/11/08: !!!
I do not recommend installing 3.4.3!!!
TBR-119, Q900 V3 and now my own V4 all have problems booting after a while with 3.4.3.
If your Q900 (without reset button) gets stuck on boot:
Connect anything to the USB A port that drains power and let the internal battery run out.
you can reisnistall older firmware on the next start.
Guohetec wrote in the WhatsApp group that they are working on it with priority on the issue with 3.4.3 and posted 3.4.2 in the group and now on their website. But they did not take 3.4.3 down.
If you prefer a zip file, you can get it here:
V3.4.2 for PMR-171 and Q900
While it was working I did some testing with 3.4.3 on my Q900 V4:
– Nothinhg has changed concerning TX audio quality (distortion and NFM issues)
– About 3W lower power output on HF SSB mode.
– The added High power mode for VHF/UHF does not really work. (switching between 5.0 and 5.7W on 12V on UHF and no change on VHF.
– I lost stored chanels and call sign, but everything came back, when I installd 3.4.1 again. But it is possible to store everythint again with 3.4.3.
I’ve been asked to upload some older versions of the firmware. I don’t know how well these versions worked.
This is what I tested myself: Q900 V4 will only work with with 3.3.2 and up. It will also boot with 3.1.8 and 3.2.1, but there is no TX power output. With 3.1.6 and lower the Q900 V4 will get stuck with both LEDs on. I had to use the reset button (not all V4 have it) to reboot and install firmware again.
Q900 version 3.4.1
Q900 version 3.4.0
Q900 version 3.3.2
Q900 version 3.2.1
Q900 version 3.1.8
Q900 version 3.1.6
Q900 version 3.1.4
Here is the last version from the Radioddity website 3.1.1. It will only work with Q900 V3 and probably V2:
It is the last version with known acces to the service menu.
QR20-version-3.1.1
For details about how to access the service menu refer to:
Ailunce HS2/Radioddity QR20/Q900 SDR Transceiver
When I get the time I will make a section about this on my website because this is a workaround for the distortion issue on TX full power (not low power).
After accessing the service menu, turn „POWER LIMIT“ to OFF.
!!WARNING!! – TX power will go up to 30W! Don’t blow your finals!
Thanks to César from the Community for this information. He tested it on his Q900 V3.
Android apps
QRadioBLE