Very often the analogyes are rather incorrect, but this lack of
precision gets an "acme" when talking about contesting.
Human or car races can't explain a complex situation, the amateur
radio contest, were the competitors are finally playing a different
game because placed in different locations and dealing in different
situations.
Each experienced contester should have this fact well clear in his
mind and who has not experience yet, should start to think about it
seriously not to get disappointed then.
Everybody aiming for results in contesting should know at least the
minimal basis of short wave propagation, the WPX debate is clearly
showing this is not always true.
Short waves can't reach all the points of the world following the
earth surface or by a single ionospherical reflection.
The shape of our planet, the respect of trigonometrical laws, and
the phisical features (limits) of the reflecting media are the
unavoidable elements to deal with.
Latitude and other geo/geomagnetical situations often make things
even more complex and peculiar, but this is out of this speech.
(btw, a reading of some book extensively threating about propagation
is always recommended)
In any case, to reach a distant point, a radio wave has to be
reflected one or more times by the ionosphere and each of the "hops"
causes an attenuation of an average extimated 10DB extra (added) to
the inherent path loss.
A second ionospherical reflection include also a reflection by the
earth surface so, 1 hop is 10DB but 2 hops is 30DB.
As a remind, 10DB attenuation means that only 10% of the original
power is left, 30DB that the left power is only 0.1% .
If a little 2-3 DB could make to copy or not, an extra 20 DB is an
enormous amount, often impossible to be overcomed.
Unfortunately the above situation it is not the worse possible,
infact, lowering the used frequency, the reflection by the ionosphere
takes place only when the incident angle gets bigger so bringing not
to a add another single hop, but often to add a number of extra ones
in order to reach a stated area.
The above clearly fix one point, who need more hops for a stated
path not only suffers by shorter openings, but mainly is subdue not
to receive or not to be received by a great percentage of stations.
It's easy to realize why a W6 who has never been in W1 or in Europe
can't believe how big is the europeans number, likewise a western
european can't have an idea of the W6 or JA population. Another
logical deduction is that in low flux conditions, when there is no
alternative to a low band use, this differences are enhanced and the
opposite is true when sun spots give 10 meters suitable for contacts.
This also explains very well why reasonable similar (effective)
pile up's are possible both east and west coast USA to Europe on 10
and 15 meters (angles as low as 2 degrees reduce the required hops to
few unity), while it doesn't exist on the lower bands even if using
monster monobanders in one of the 2 edges.
73,
Mauri I4JMY (one of IR4T)
e-mail i4jmy@migate.ampr.org
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