Stefan,
Thank
you for the information. I was hoping for input from you and Uwe on ERP
and antenna angle, and your information is very helpful.
Regarding
antenna angle:
I
am hoping to detect T/A VLF signals, and a long integration time is
important. Without special integration algorithms, changes in phase of
the received signal limit maximum integration time. Even at T/A
distances, low antenna angles (angles far from vertical) can increase
the sensitivity of phase to day/night transitions and other
environmental/ionospheric factors, and thus limit maximum useful
integration time. All of the above is for a constant non-vertical
antenna angle; maximum useful integration time is even less when the
antenna angle varies.
I
don’t have solid numbers for phase vs. antenna angle, orientation and
distance yet (the phase variations of interest are of multimodal
origin, so multimodal analysis is required), but the information that
you provided will help very much in converging to an estimate of
maximum useful integration time with conventional integration
algorithms.
For
T/A VLF signal capture planning purposes, do you think that it would be
safe to say that, in the next year or so, most amateur antennas long
enough for potential T/A VLF communication will either be nearly
horizontal (fixed at both ends), or fixed at one end with a variation
in angles as in the example that you gave below?
