Festival of Frequency Measurement 1 October 2019 for WWV 5 MHz - Toby Haynes VE7CNF

Festival of Frequency Measurement 1 October 2019 for WWV 5 MHz

Toby Haynes VE7CNF
Location:    49.266918N   122.900887W   Grid CN89ng   Burnaby, BC, Canada
Start Time:  2019 Sept 30 at 23:58 UTC
End time:    2019  Oct  2 at 00:02 UTC
Antenna:     "Inverted L" vertical with ICOM AH-4 auto tuner, 50 ft high, 70 ft horizontal top wire.
Receiver:    ICOM IC-7410 with internal TCXO reference and internal USB sound card chip with separate clock crystal.
            Receiver in USB mode with carrier frequency 4998.5 kHz to give a 1500 Hz audio tone for the WWV 5 MHz carrier.
Measurement:  1500 Hz tone frequency estimated using program FLDigi v4.1.08 in frequency analysis mode.

There was a drop in the WWV 5 MHz signal level around 15:00 UTC, after which the reduced SNR caused more variation in the FLDigi frequency measurements.

Frequency calibration:

Before and after the data set, the receiver frequency error was determined by using the receiver and FLDigi to measure a reference 5 MHz sine wave from a Rigol DG1032 function generator with external 10 MHz GPS-disciplined frequency reference (Trimble).
The "VE7CNF raw_2019-09-30-1810 UTC.csv" file includes the reference measurements and the data set.

The two reference signal measurements were:
   Receiver frequency error +0.066 Hz averaged for 1 minute starting 2019 Sept 30 at 18:10:25 UTC 
   Receiver frequency error +0.028 Hz averaged for 1 minute starting 2019  Oct  2 at 00:03:10 UTC

Receiver frequency error at each time during the data set was then estimated, assuming that the error changed linearly over time betwen the two reference measurements. The estimated receiver frequency errors were applied to correct the data set in "VE7CNF CN89ng 5 MHz_2019-09-30-2358 UTC.csv."

The measured WWV 5 MHz frequency error vs time is graphed in "VE7CNF_WWV5MHz_2019-10-01UTC.JPG," with a moving 1-minute average applied to the frequency error. The frequency dropped around 01:30 (local sunset was 01:51 UTC) and increased around 14:00 (local sunrise was 14:13 UTC).