Joe & EbNaut-eers

 

Had not checked in on VO1NA LF EbNaut for some time so decided to have a look. Immediately noticed the unusually large spread between car Eb/N0 and Eb/N0. Inspection of the phase plots revealed the problem ... there were two minute periods of 'disruption' on an otherwise clean phase plots. By matching up the observed 'disruption' times with the WSPR database I was able to determine the interfering signal was WSPR and belonged to K3RWR (one of the strongest LF signals at this location). Considering K3RWR's signal is outside the SpecLab FFT bandwidth the problem is most likely happening at the receiver ... a Cubic SMA-2400. AGC was turned on at the time to prevent audio distortion from the stronger WSPR signals. When time permits I'll run another test with AGC turned off.

 

Last night's reception list:     

 

0130 Rank 0 car Eb/N0 16.2 Eb/N0   8.9 *******

0200 Rank 0 car Eb/N0 20.1 Eb/N0 12.3 **VO1NA

0230 Rank 0 car Eb/N0 29.1 Eb/N0 15.3 *******

0300 Rank 0 car Eb/N0 27.9 Eb/N0 15.6 **VO1NA

0330 Rank 0 car Eb/N0 28.0 Eb/N0 13.3 *******

0400 Rank 0 car Eb/N0 28.7 Eb/N0 11.9 **VO1NA

 

Phase plot below.

 

 

Jay W1VD