miniVNA tiny - generator output level

Some months ago Andrew Rich, VK4TEC and Geoff Robinson, VK4KJJ provided me a chart where they measured the generator output level over frequency:


They used a ROHDE & SCHWARZ NRP2 with an NRP-Z81 power sensor.

After I've finished my new RF power meter, I decided to repeat the measurement with my miniVNAtiny and the RF head from SV1AFN.

01 01 2017 11 02 37

The plot is basically identical, except the absolut values. In my configuration, the output power is much higher than the VK guys measured.

Now the good question is - why?! VK has used a bit more expensive equipment over frequency.

On January 21st, Evgueni provided me a diagram of his miniVNAtiny using an HP 8594E Spectrum Analyzer.


There seems to be slight variations in the output power of the miniVNAtiny ...