(I am putting this on reflector in order to open the eyes of those who are
interested:
In a message dated 97-11-12 00:10:59 EST, Garry, NI6T writes:
<< Brown does not deny skewing associated with ducting. But his
simulations, while showing the dramatic dependence of ducting upon the
geomagnetic field, only show a few degrees of skew.
I am not denying anyone's observations, but do you know of any
analytic
work that justifies, explains, or confirms large skews? >>
Hi Garry,
I am practical; engineer. If I see something happening I believe it, use it,
and beat the competition in the contest with it.
I don't care what Brown or other "scientists" say or explain, or what some
mickey- mouse software says. (I'd like to meet them, in the contest!) The
skewed propagation I have seen from 40 down to 160 is in order of up to 30 -
45 degrees (azimuth). The only thing I do not know is the possible vertical
angle of signals entering and exiting the duct. Did not have the chance to
seriously observe it, had no antennas specifically set up to detect that.
>From casual experience (operated K3BU in 97 160m CW from Cape Henlopen DE)
with being forced to run low - 40' Inv Vee - Radials (too windy for balloon),
I found it easier to get the Eu stations to answer me than I was accustomed
with balloon vertical. So my suspicion is that we need higher angles. I will
try to have some high angle TX antenna in CQ WW CW from VE1ZZ place, see if
it helps. In VE1 I would start hearing Eu around 3 pm they would start
answering me around 7:30 pm. Jack had only 4 square on TX.
What's your hangup with "analytic work"? I find that things are
discovered by experimenters or by accident, and then the guys in white coats
get wind of it, start studying it, write papers, present them at the
conference of white coats, get the glory, while the real inventor doesn't
even get mentioned. I tried to submit my paper on ducting radio propagation
theory to RadioScience conference in Montreal in 80s, but was turned down.
What some poor slob ham knows? Us, "scientists" in white coats and
calculators know better. Right?
I tell you another "shocking" discovery I made, that is not mentioned
and doesn't fit bouncing theory ("mirrors" should be working the same way
both ways): There is in order of 70 - 80 % disagreement between RX and TX
antenna (which is better at the time). If you have bunch of stacked beams or
multiple antennas at various heights, try to get reports on transmit and
correlate them to reports you see on receive. I could not believe what I was
getting (20m and up)! I used that in the contest, periodicaly I would do a
check "number 1 - 2 - 3" and keep the better TX antenna on while running
particular area. RX antenna was switched as needed.
Same goes for antenna modelling software, I see so many "designs" taken
so seriously. Everybody with antenna program is designer now. I tell good
antenna, when it can hear (work) something that the other antenna can't. That
is the ultimate test, and not what the plot shows. (Computer simulation is a
handy tool, and I inted to use it, but for a guidance, and not as a gospel.)
When designing my Razor Beams, I have seen so many variables and
disagreements with "paper" wisdom, that I opted for experimental route and
spent 4 months designing antennas on the test range. It sure made the
difference, gave me 1 to 2 hour jump on W2PV.
Another important factor in RX vs. TX antenna that is usually overlooked,
is role of surroundings and terrain. ON TX generally you trying to have
antenna up and unobstructed to get the max energy at the best momentary angle
out. On receive you can have surroundings (atmosperic conditions, etc.)
playing games being something like a lens or a dish, or reflecting plane.
This provides some focusing and/or rejection. Have you heard stories about
the guy in the valley hearing better than one on the hill? Or difference
being on different sides of huge power lines? Or driven in a car and
listening to marginal station and all of a sudden signal coming up 10 - 20
dB, and it is only in that particular spot? This is why I suspect that we
might need high angle TX antenna to get at those one way Eu at the beginning
of the opening (our sunset).
The point is, don't believe everything you read, paper can take a lot.
Get the wires or tubing out and play with them. I am slowly gearing up to
crack the "puzzles" and would appreciate the reports and observations on my
signals and other's during the upcoming contests. I will be on 160 this
season and will try to add some more antennas and noise fighting gadgets to
my arsenal. Right now recovering from an operation, and pain permitting,
sprucing up IC781 and TS870 and DSP and phasing gadgets, and....
Hope this helps to wake up some into reality from the "virtual and calculated
science". Boy, I love that noise, one way and skewed propagation on 160!
Active 160 m operators can shed some light on what is happening, make it
known to newcomers, so they can enjoy the band by knowing more than what we
did.
73 for now
Yuri Blanarovich
K3BU, VE3BMV, P40A
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