Quote:
Relative "badness" of interference is the same at 200 meters (hangflywer stated direct line of sight to base station antennna) or at a significant distance, 20km would result in 40db Rx level difference.
You are implying, as I read it, that at 20km from the base transmitter, the signal is still readable and the apparent noise has reduced relatively by -40dB?
Are we looking at some form of cross modulation, which includes a noise component?
Basically yes, although the 200m is a fact the 20Km is an estimate I dont think hangflyer gave an exact number for max range.
The point is that the signal to (unwanted) noise ratio is staying the same over an impressive range of Rx signal levels.
As I postulated in prior posts I suspect some sort of signal cancelation (or possibly even boosting) effect, either from the prop (unbonded over a critical speed) or some other metalic element vibrating between bonded/unbonded. The ADF antenna is currently one prime suspect.
With just the right dimensions this would cause a significant and rapid Rx level fluctuation that could cause the AGC circuits to wig out.
Importantly this would also account for the extreme directionality of the "noise" since it would only happen if the element (approximatly) in line between the antenna and base station.