[regenfreak]

The HP 3324A fails its self-test during every start-up. It shows the VCO error unlock at 30MHz...I guess it means the PLL cannot lock onto the clock ref frequency of 30MHz. It will be returned for refund. Oh well the HP 3324A is very bulky, I probably struggle to find space to put it, a glass half full.

My plan for two tone IP3 measurement has been thrown out of window. My intention was based on Marki's web site methodology:

two-fundamentals of 7MHz and 7.1MHz centred at 7.05MHz through two low-pass diplexers, 10db attenuators before the combiner, a bandpass diplexer before the ring diode mixer. The LO will be 17.75MHz and IF = 10.7MHz. The IF output bandpass diplexer (has to be relatively wideband, higher L/C ratio due to the two tones) is the most important one that it dumps all low and high-sided IMD energy through the 50 ohm loads, instead of reflecting back to the mixer and going into the spectrum analyzer's mixer. So 3-4 diplexers would be needed. It has become increasingly apparent that it is too much of a hassle and equipment intensive to do such a measurement.