Propagation is king, but hams can do things to improve contact
probability and lessen the effects of fading.
>This is exactly what the models predict. It turns out that if you model two
>paths, separated by 2 milliseconds, with random phase, you get Rayleigh fading
>with 10-20 dB fades. I forget what speed the "ionosphere clouds" >move at,
>but it's related to that - think of the ionosphere as a very lumpy medium with
>blobs that are several hundred meters in size all moving around.
When I was in the Army we employed diversity reception and
transmission to combat this. This method is out of reach for most
hams though.
When it comes to dB increases, some hams tend to go to power, but
often, a few dB or more! can be found with less costly antenna system
improvements such as adding a reflector to a dipole, or raising a
dipole an additional 1/8 wavelength, or adding radials to a ground
mounted vertical. I'm thinking about low band antennas on those last
two.
W6AM dominated the high bands in his day, and it was all antennas for
Don. Of course no one could duplicate Don's rhombic antenna farm
today, but the OTs knew to put their efforts into skyhooks first,
power second.
Rob
K5UJ
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