Hi Kris, If you belong to the shared apex loop Yahoo Groups click on the file tab and then look for my call sign. You will see plots that I generated looking at the front to back ratio versus elevation angle, and I think these plots might help answer some of your questions.
Don (wd8dsb) On Thu, Jan 14, 2016 at 4:33 PM, Kris Mraz <n5kilom...@gmail.com> wrote: > I know that fading can be caused by phase rotation of the arriving signal. > Can fading be caused by the signal changing arrival angle over time > (1-3 seconds)? > I ask this because of something I observed while attempting to tune my > Shared Apex Loop (SAL) > antenna the other night. > > In the forward direction I tuned in a strong, distant AM broadcast > signal that was fairly steady > strength-wise. It would vary less than an S unit as seen on my radio > S-meter (FTdx5000). Then I > switched to the reverse direction. From the SAL backside the signal > experienced rapid fading > from S0 to S8. > > Looking at the elevation pattern of the SAL (or just about any RX > antenna design) it can be seen > that the forward direction has a broad gain pattern around the 20 > degree arrival angle. In the reverse > direction there is a deep steep null near that reverse angle. From > this I assumed that the signal was > changing arrival angle, moving into and out of that deep null. Is this > the correct analysis? > > > Kris N5KM > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband