K5CM Dual Tone Frequency Measurement Test Reception: 17-May-2012

On May 17, 2012 at 0200 UTC, Connie, K5CM, made a Frequency Measurement Test (FMT) transmission consisting of two carrier frequencies, each referenced to a GPS-disciplined frequency standard, and spaced approximately 2 kHz apart.

The transmission was received in New Jersey using a receiver whose AM detector was used to heterodyne the two carriers together, thereby producing an audio tone equal to the frequency difference between the individual carriers.

This video plots demodulated audio voltage as a function of time, and illustrates the phase stability of the recovered audio tone, bandpass filtered to a 10 Hz bandwidth, and referenced to a local standard.

Frequency stability of the received signal was excellent, with some interesting cyclic phase shifting taking place during the transmission period due to propagation effects.

RF frequencies employed during this transmission were as follows:

Carrier #1: 14120000.000 Hz
Carrier #2: 14122000.277 Hz

Delta = 2000.277 Hz

Видео K5CM Dual Tone Frequency Measurement Test Reception: 17-May-2012 канала 5UP7