Composite VFO Noise Measurements (ARRL Lab)

Here are measurements for composite noise on three separate Hagerty Radio VFOs, which includes phase noise, performed by Bob Allison, WB1GCM at the ARRL Lab during the week of 4/19/10. These were performed on the calibrated measurement equipment recently donated by Dr. Ulrich Rhode, N1UL. The VFOs were set up at follows:

  1. Standard construction, with Crystek CCHD-950 low-noise, 125 MHz clock oscillator.

  2. Standard construction, with Connor-Winfield TCXO (117.5 MHz) clock oscillator.

  3. Standard clock oscillator (Connor-Winfield AC-52 at 150 MHz); with the microprocessor and crystal mounted on a separate circuit board, and the six shielded control lines (RG-174 coax cable) running over to the DDS board.

Note: Carrier output for each measurement was set to 14.025 MHz for compatibility with the measurement equipment. Noise level is in dBc (db down from the carrier) and the horizontal axis is: frequency spacing away from the carrier.

Many thanks to Bob Allison for performing these measurements.