Frank, I have never focused on the reflection points. But obviously, that is
where the interaction is most critical.
I notice that my path to EU is virtually the same as K3LR, just somewhat
shorter.
73 and thanks for the info and enlightenment.
Ed N1UR
From: donovanf@starpower.net [mailto:donovanf@starpower.net]
Sent: Tuesday, March 1, 2016 7:00 PM
To: cq-contest@contesting.com
Subject: Re: [CQ-Contest] Ohio is now West Coast - rebuttal
Hi Ed,
The first ionospheric reflection point for propagation from
K3LR and W3LPL to Europe is over Eastern Canada. For high
angles its located near the U.S border, for low angles it near
Labrador and Newfoundland.
There will usually be at least one additional ionospheric reflection
point, in the North Atlantic west of Ireland. For both reflection
points and for any specific propagation path to Europe, K3LR's
ionospheric reflection points are about 200 miles NW of W3LPL's
reflection points.
Normally 200 miles wouldn't make much difference, but near 60
degrees magnetic latitude the difference in MUF is sometimes
significant. The mid-latitude trough frequently (but not always)
occurs during darkness near 60 degrees magnetic latitude during
the fall and winter and sometimes the more southerly reflection
point will be outside the trough while the more northerly reflection
point may be in the trough. When this occurs, the MUF will
degrade earlier in the day for K3LR than for W3LPL.
You can clearly see the electron depletion caused by the
mid-latitude trough in this NOAA Total Electron Content forecast
map:
http://www.swpc.noaa.gov/products/ctipe-total-electron-content-forecast
There is good news: because the mid-latitude trough is mostly a fall
and winter phenomenon byy late this month (WPX SSB), late afternoon
and evening propagation across the North Atlantic will be much more
common on both 15 and 20 meters
73
Frank
W3LPL
_____
From: "Ed Sawyer" <sawyered@earthlink.net>
To: donovanf@starpower.net, cq-contest@contesting.com
Sent: Tuesday, March 1, 2016 9:38:42 PM
Subject: Re: [CQ-Contest] Ohio is now West Coast - rebuttal
Frank. Thanks for the knowledge base and I agree with your statements.
The key for my area, similar to what K3LR experienced last weekend, is the
further north reflection point and the MUF and absorption properties of that
point heading to EU or JA. That can clearly be 20 or 30 dB of degradation as I
can hear it swing up and down on 40, 80, and 160M. Take a pass on a band and
hear DL1A 20 or 30dB stronger than the last time 30 mins or an hour earlier.
If the conditions are not too brutal, then its not that big a deal. If they
are, it’s a game changer.
How many miles out are you calculating that first reflection point to be? It
depends on the angle of radiation that is favoring the day on the band in
question.
Ed N1UR
From: donovanf@starpower.net [mailto:donovanf@starpower.net]
Sent: Monday, February 29, 2016 8:16 PM
To: cq-contest@contesting.com
Cc: sawyered@earthlink.net
Subject: Re: [CQ-Contest] Ohio is now West Coast - rebuttal
Hi Ed,
The efficiency of a horizontally polarized antenna over salt water
or a salt marsh improves by one dB or less compared to the same
antenna over fertile farm soil in a flat (or nearly flat) Fresnel Zone.
Even desert soil degrades the performance of horizontally polarized
antennas by only a few dB.
On the other hand, salt water significantly improves the efficiency
of vertically polarized antennas particularly at low elevation angles
but only if most of the antenna's Fresnel Zone is over salt water or
a salt marsh. Only a few U.S. contesters have vertically polarized
antennas in or at the edge of a salt marsh or salt water such as
K1DG (at his Maine QTH), W1KM and K3ZM.
When K3LR and W3LPL are working Europe, the most important
factor is the MUF at our first ionospheric reflection points at
roughly 60 degrees magnetic latitude over eastern Canada.
Coincidentally 60 degrees magnetic latitude is a region of high
interest to ionospheric scientists, including PVRC's N3HBX who
wrote a scientific paper about his research into ionospheric
behavior at that latitude when he worked at MIT's Haystack
Observatory researching a well known (to ionospheric scientists)
phenomenon known as the mid-latitude ionospheric trough or
simply the Mid-Latitude Trough.
For any propagation path to Europe, K3LR's ionospheric
reflection is about 200 miles northwest of W3LPL's reflection
point in the immediate vicinity of the mid-latitude trough. While
the trough isn't present every night, it is present very frequently
and it causes significantly lowering of the MUF over a distance
of just a few hundred miles to the north as dusk approaches
eastern Canada. The reduced MUF to Europe steadily becomes
more severe during the night until the trough suddenly disappears
as sunrise illuminates the ionosphere as it approaches eastern
Canada.
Those interested in exploring this phenomenon can Google
"mid-latitude trough" and "magnetic latitude"
73
Frank
W3LPL
_____
From: "Ed Sawyer" <sawyered@earthlink.net>
To: cq-contest@contesting.com
Sent: Monday, February 29, 2016 5:56:25 PM
Subject: Re: [CQ-Contest] Ohio is now West Coast - rebuttal
Arguing the "West Coast" is not NM is no different than calling W1 just W1.
W1 and W2 are equally as capable in the DX contests to win, it depends on
where you are in W1 or W2. And the area is not homogenous in capability.
W1WMU, K8PO, K1DG, K1ZM, and W1KM are all within the Fresnel zone of salt
water or salt march to EU. There are equally great areas in W2 and all the
way down to K3ZM's location that define as much a universe within W1, W2, W3
as NM vs CA.
As a W1 that is 50 miles from the Canadian border and literally 350 miles in
the EU direction from salt water, I can tell you that W1 is NOT all the
same.
Don't get me wrong, its better to EU than W6/7, but I drool listening to the
saltwater stations run loud and early just like you do listening to W1 in
general. There are time when it matters BIG and times when it doesn't
matter as much.
K3LR's more northern path to EU vs W3LPL was "just enough" with disturbed
conditions that I witnessed much further north than them to change the game
on K3LR.
Broad brushing conclusions is not a wise idea.
73
Ed N1UR
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