I found on the internet that some of these Chinese analyzers like SARK100/MR100 have a serious problems with their DDS chip. This resulted in an output frequency being 1.5 times lower than what was displayed on the analyzer. To check if this was the problem with my analyzer I did a quick test.
Simply I connected the MR100 module to Agilent Frequency Counter in my laboratory and set the filter as same as input attenuator ON.
After I switched 160m thru 6m band range in order to check the frequency accurracy as same as stability.
The results can be seen on the pictures below:
The laboratory test conditions: T=25.5C +/-0.5C, Hum=45% +/-15%.
It looks like this module works as it should. The articles I read about this problem were all older articles so I guess it’s an old problem that doesn’t occur anymore?!
Hope it helps.
73 - Petr, OK1RP