Thanks to Machaca for posting the pics a couple of pages back, having looked at them for a few moments and understanding the fact that the new antenna attached to the underside of the aircraft works perfectly (still true hangflyer?) really does bring into question the interaction of the ADF antenna and the comm antennas.
So a flight with the ADF antenna removed or even just ground tests would be revealing. Somewhat obviously, the fact the ADF antenna is inline with the orientation of the aircraft, which also corresponds to the directional confluence when the problem is heard would seem compelling.
I'm still not sure I can understand how/what the prop RPM setting can have over the behavior though - if the ADF ant. is causing some kind of RF shadow to fall over the VHF upper body antenna, how is RPM (above/below 2250RPM) factored into the equation? I presume some vibration effect?
A real puzzle indeed!
- GY
P.S. DERG - yes, VA is a nice place to live, but I'm not sure I'm totally lined up with the tanker decision - though in the end I suspect the Air Force would have been able to make either option work. Living as close to Wash.D.C as I do, there are far more politics in the decision than fit-for-purpose - my perception is Boeing has far stronger lobbyists than EADS could muster, ergo Boeing wins. In the first go-around Boeing simply didn't think it could lose... until it did, hence the re-compete.