Carrier Cancellation

[tony_ccd]

I now have a noise cancellation box for 6m, which uses switched coax's and gain controls to adjust cancellation. The main antenna is an upward pointing Moxon, and the auxiliary is a 4 element yagi pointing towards the beacon. Careful gain adjustments and selecting one of 6 switched delays plus a 180 degree switch gets pretty good direct carrier cancellation. I am only 50km from the beacon. In the attached plot, I am switching the 180 degree cancellation every 30 seconds. It can be seen that the direct carrier becomes strong with the switch in the 'wrong' position, but the aircraft trails are barely affected. Unfortunately, no obvious meteor echos this lunchtime.
The noise canceller is from a design by G3ZYY first published in Rad Com April and September 1992