Hi.
It looks like you are having the dreaded Clock Generator instability around 300MHz. You can see the spurs around 300 and 600MHz on the yellow traces in your photos.
The basic design of the NanoVNA severely overclocks the 5351 Clock Gen chip which is only specced to 200MHz max.
Some chips just can't make it to 300MHz, especially the Chinese knockoffs.
Go into your configuration and look for something called THRESHOLD. It will be 300MHz at present.
Change this to 280MHz.
Clear all your existing calibration data and recalibrate.
This should fix your problem.
I have a Deepelec unit so I can't give you the exact menu steps for your unit.
There is a Menu Map available elsewhere on this group, just follow the path to the THRESHOLD item.
Good luck....Bob VK2ZRE
toggle quoted message
Show quoted text
On 31/08/2022 4:50 am, TE Dukes wrote:
HA!! Didn't know I could do that!!
Here at the pics. The green lines are moving.
Thanks!!
