Hi,
For clarification: An SI5351 outputs square-wave signals that contain only odd multiples of the fundamental frequency (3 * f, 5 * f, ...).
To reach 1500 MHz, 7 * 214.285 MHz are therefore required as fundamental frequency.
In the analyzer according to EU1KY, however, we did not go beyond 5 times, and I reached e.g. 1450 MHz with 5 * 290 MHz. Prerequisite was a test of the maximum possible frequency of the SI3531 circuit.
Wolfgang, DH1AKF
Wolfgang Kiefer