[amsat-bb] Fwd: White House wants to eliminate WWV

[oh2aue at kolumbus.fi]

Beware: HF content !

In addition to the obvious time and frequency applications there is also 
a
plethora of propagation science that can easily be accomplished by even
us mere amateurs.

To demonstrate x and o mode propagation, I have often used a setup where 
I
GNSS PPS trigger a regular analogue or digital oscilloscope measuring 
the
audio beat of the received timing pulses. In this manner,the o/x mode
superimposed, time delayed aggregate pulse can be observed and the 
individual
time variant (multipath) fading of the LHCP and RHCP combination can be 
very
easily observed and visually separated on the scope screen with a 
regular
HF receiver and e.g. simple (linearly polarised) dipole.

Obviously both propagation paths can be observed separated in a similar
manner using a dual channel oscilloscope and a circularly dual polarised
HF antenna. Extremely interesting to study as the x and o mode MUF's
creep past the frequency of observation as a function of E and F layer
ionisation:

http://www.kolumbus.fi/michael.fletcher/HF_layer1_oblique_nvis_propagation_analyser_block_diagram.gif

http://www.kolumbus.fi/michael.fletcher/60m_band_1000km_oblique_o_mode_x_mode.jpg

Michael OH2AUE