In addition to what Erik just said, if you ever perform a full clearconfig command via the console or install new firmware, you will need to reset the threshold level again.
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On Wednesday, January 8, 2020, 11:33:47 a.m. GMT-5, erik@... <erik@...> wrote:
Officially the maximum output frequency of any SI5351 is 800MHz divided by 4 is 200MHz.
Many will be able to produce 300MHz but the increase of the VCO of the internal PLL to 1200MHz implies the SI5351 will become much hotter and it is being considered "out of spec"
So you can not formally buy a SI5351 that will go to 300MHz.
If you have a problem with the SI5351 on a nanoVNA not being able to reach the out of spec 300MHz there is a build in solution that will reduce the maximum frequency of the SI5351 before it switches to harmonics mode.
You need to connect to the nanoVNA in console mode using a terminal emulator (putty or any other) and use the "threshold" command to verify at which transition to harmonics mode the problems disappear. This could be any value between 200 and 300 (MHz). Once found you do a "save conf" from the console to store the max threshold value so it will be remembered even if you power off.
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NanoVNA Wiki:
/g/nanovna-users/wiki/homeNanoVNA Files:
/g/nanovna-users/filesErik, PD0EK
