Thanks for your help.
One question: Is the soft recet mandatory? this means that whenever I weant to perform the DSM test I have to re-init the HMC384 device.
I have repeated the HMC7044 with external VCO test with HMC384 - VCO with frequency range 2.05GHz-2.25GHz and again the on board 122.88MHz VCXO is used. No problem when locking to 2088.96MHz and 2211.84MHz by setting N2 divider as 17 and 18 respectively…