SDRplay Community Forum

I’m trying to set up a Raspberry pi to remotely control an RSP 2, I’ve downloaded the image and it works great locally. However when I use VNC to log on to the pi I run into a problem.

If I’ve got a monitor connected to the pi the VNC session opens in the same resolution as the monitor, which is good. However if I run the pi without a monitor, I.e. headless, VNC will only open at a default resolution of 720 x 480 and I can’t change it. This is far too small for apps such as Cubic SDR.

I’ve followed the instructions for changing resolution on VNC’s web site, I.e. editing the pi’s config.txt file. But whenever I run the pi headless with the SDRplay image it will only open at 720x480. If I boot my pi using a standard raspberry pi image I can set the VNC display to whatever I like in headless mode. It looks like something in the SDRplay image is overwrite is the pi’s config file to put VNC back to default.

Where do I look to get my VNC sessions for a headless pi running on a better resolution?

sudo nano /boot/config.txt
fix "dtoverlay=vc4-kms-v3d" on "#dtoverlay=vc4-kms-v3d"
reboot

Note the above command will DISABLE hardware acceleration which is required for applications like CubicSDR to run properly. So use with caution.

Best regards,

SDRplay Support

Hi,

tolot is correct in that you must edit the /boot/config.txt file. The following lines can be added/edited in the config.txt file:

#trick the Pi into thinking that something is connected to the HDMI port (use if running headless)
hdmi_force_hotplug=1

#force HDMI group 2 modes
hdmi_group=2

#force hdmi_mode for external monitor and VNC remote access
hdmi_mode=82

#for reference...
#hdmi_mode=81 sets a resolution of 1366x768 @ 60Hz
#hdmi_mode=82 sets a resolution of 1920x1080 @ 60Hz
#hdmi_mode=35 sets a resolution of 1280x1024 @ 60Hz
#hdmi_mode=16 sets a resolution of 1024x768 @ 60Hz
#additional configuration options are available here:
#https://www.raspberrypi.org/documentati ... t/video.md


Please note, when you force an HDMI mode using the above method, you not only force the resolution for VNC but also any monitor attached to the HDMI port. So, be sure the mode you select is compatible with your monitor if you intend to run the Pi with a display attached.

Thanks for the replies. I’ve now got my VNC session running at 1280x1024, the same as when I have a monitor connected.

I’m in the process of setting up my RSP to be remotely controlled, am trying various things to see which works best for me.