On Thu, 14 Dec 2006 23:52:22 -0500, "C. J. Clegg"
wrote:

On Fri, 15 Dec 2006 02:25:42 +0000, Owen Duffy wrote:

Do you know what f0F2 was at the path midpoint, or are you depending
on interpolation?


You missed my point, it isn't so much as the exact location of the
virtual midpoint, but is there an ionosound measureing that point, or
is the map constructed by interpolating measurements from just a small
number of ionsondes, and is the interpolation sound?

Well, the path midpoint was pretty much straight up, or maybe up to 20
degrees off of vertical. foF2 all along the path was just a bit under 3
MHz. Frequency of operation was well above 4 MHz.

In this neck of the woods, there is abundant sporadic E,

I should have added "at this time". But sporadic E is most likely
around the solstices, so you should be seeing a bit in the northern
hemisphere.


I don't really know much about sporadic E, have a vague idea what it is
and that's about all, but doesn't it assume that there is an E layer to
begin with? This was about 7:30 PM, sunset was around 4:45 PM, and the E
layer would have been pretty much gone along with the sun, wouldn't it?

Sporadic E does not depend on sunlight, it is one of the mysteries of
Es.

Owen
--

On Fri, 15 Dec 2006 08:09:45 +0000, Owen Duffy wrote:

You missed my point, it isn't so much as the exact location of the
virtual midpoint, but is there an ionosound measureing that point, or
is the map constructed by interpolating measurements from just a small
number of ionsondes, and is the interpolation sound?

Oh, OK, I get it.

I have no idea. I use the map at http://solar.spacew.com/www/fof2.html
and I don't know how they get the information they use to build that map.

Sporadic E does not depend on sunlight, it is one of the mysteries of
Es.

Doesn't sporadic E normally affect the higher frequencies, 15 meters and
above, rather than the lower frequencies around 75 meters?

On Fri, 15 Dec 2006 09:08:09 -0500, "C. J. Clegg"
wrote:

On Fri, 15 Dec 2006 08:09:45 +0000, Owen Duffy wrote:

You missed my point, it isn't so much as the exact location of the
virtual midpoint, but is there an ionosound measureing that point, or
is the map constructed by interpolating measurements from just a small
number of ionsondes, and is the interpolation sound?

Oh, OK, I get it.

I have no idea. I use the map at http://solar.spacew.com/www/fof2.html
and I don't know how they get the information they use to build that map.

Sporadic E does not depend on sunlight, it is one of the mysteries of
Es.

Doesn't sporadic E normally affect the higher frequencies, 15 meters and
above, rather than the lower frequencies around 75 meters?

Here is an ionogram from the station in Canberra this morning about
1.5 hours before sunrise.

http://www.vk1od.net/lost/ionogram.gif

Note the E layer at 100km height, very well established. It is so
intense, that there are multiple E - earth - E - earth "reflections".
You can see the F layer above it, and f0F2 looks between 2 and 3MHz.

(I believe that the existence of such a strong E layer before sunrise,
and the height in the 90km to 100km range characterise sporadic E.)

Sometimes the E layer reflection is so intense, that there isn't a
hint of the F layer. I don't know how they assess f0F2 under those
conditions, but they still produce the statistics.

I think you may be reading more accuracy into the maps than is safe.

As for "normally affecting higher frequencies", here you can see the
ionsonde discovering the Es layer at up to about 10MHz. When you take
into account oblique paths of a couple of thousand km or more, the Es
here with critical frequency up to about 10MHz should reflect 50MHz
ok. Now exploitation of that depends on such a patch of Es in the
right place, angled the right way, between two stations attempting
communication. There have been some big openings on 6m here in the
last week or so, not huge, just the seasonal openings typical around
the solstices.

Owen
--

Owen is correct- and anyone operateing 10& 6
meters will tell you the same thing! Have
been on 6 for around 45 years now, an can attest
that "E" openings can occur ANYTIME, day, or nite!
And, the "E" layer is ionized , to a degree, 24
hours per day (There are more than a few running
"Scatter", with power levels of 100-1KW makeing
contacts, when the band(s) are literally closed ).
Es is the "bread and butter" of the VHF operator,
rangeing from 35-400 miles for super intense
openings, out to 1200, or so miles, when the band
is barely open. Figure stations (on scatter), from
Montana, New Mexico, Colorado, and Wyoming being
copied with NO major opening, into Reno, Nevada!
And, keep in mind, you also get Double hop, 2
adjacent (or more) layers , giveing you cross
country capabilities. One further thing: IF
you shea short E skip on a band (say 10 meters),
odds are great that 6 is open; Same for 6 meter
short skip, often means that 2 meters, or at least
F.M.Broadcasts (88-108 MHz) will be open!. F2
is associated with sunspots-Es seems to get worse
as sunspot activity increases!Might you find this
interesting? Jim NN7K

Owen Duffy wrote:

I don't really know much about sporadic E, have a vague idea what it is
and that's about all, but doesn't it assume that there is an E layer to
begin with? This was about 7:30 PM, sunset was around 4:45 PM, and the E
layer would have been pretty much gone along with the sun, wouldn't it?

Sporadic E does not depend on sunlight, it is one of the mysteries of
Es.

Owen
--

Jim - NN7K wrote:
Couple errors (I ain't a professional typeist)!


rangeing from 35-400 miles for super intense

Make that 350-400 miles!

One further thing: IF
you shea short E skip on a band (say 10 meters),
odds are great that 6 is open; Make that


"HEAR", not "shea"! Jim

On Sat, 16 Dec 2006 01:22:44 +0000, Jim - NN7K wrote:

Owen is correct- and anyone operateing 10& 6
meters will tell you the same thing!

Good morning, Jim.

What I'm trying to figure out is the effect of sporadic E on the lower
bands, e.g. 75 meters.

I was on a military net on a frequency somewhat above 4 MHz and was able
to work a station 70 miles away, well after dark when the critical
frequency was below 3 MHz. According to everything I know about critical
frequencies and MUF (which isn't very much), my NVIS signal from my
17-foot-high dipole should have gone right off into space, and the
70-mile-away station shouldn't have heard a peep out of me (and vice versa).

I'm trying to figure out if the solar storms of the last few days might
have something to do with why I was able to contact that station when
every indication was I shouldn't have been able to. Sporadic E? I dunno,
maybe, but it seems like quite a stretch...

People are staring to take the computer predictions, simulations and
forecasting too seriously. Atmosphere and ionosphere are very complicated
and are run by Sun and not some wiz programs.
Before the computer models, we used to OBSERVE and LEARN about propagation
from our activities on the bands. Changes with sunspot cycles, time of year,
day etc.
So forget the computer prescriptions and observe and make notes what is
happening when Sub is doing what. One general observation I have found that
with low sunspots in a cycle atmosphere shrinks, angles get lower and
antennas with low angle lobes work better. At High sunspot, atmosphere gets
higher and angles get higher and higher frequencies come to live.
The best, unpredictable and unbehaved band is 160 m, you never know what
happens, just need to be around when IT happens.
Check out http://members.aol.com/ve3bmv/bmvpropagation.htm
on my observations and notes on ducting and refraction.

73 Yuri, K3BU
"C. J. Clegg" wrote in message
news
On Sat, 16 Dec 2006 01:22:44 +0000, Jim - NN7K wrote:

Owen is correct- and anyone operateing 10& 6
meters will tell you the same thing!

Good morning, Jim.

What I'm trying to figure out is the effect of sporadic E on the lower
bands, e.g. 75 meters.

I was on a military net on a frequency somewhat above 4 MHz and was able
to work a station 70 miles away, well after dark when the critical
frequency was below 3 MHz. According to everything I know about critical
frequencies and MUF (which isn't very much), my NVIS signal from my
17-foot-high dipole should have gone right off into space, and the
70-mile-away station shouldn't have heard a peep out of me (and vice
versa).

I'm trying to figure out if the solar storms of the last few days might
have something to do with why I was able to contact that station when
every indication was I shouldn't have been able to. Sporadic E? I dunno,
maybe, but it seems like quite a stretch...

That supposed to be ...starting.... and Sun.... not Sub :-)

Even spellchecker can fail :-)

73 Yuri

Yuri Blanarovich wrote:
Even spellchecker can fail :-)

My spellchecker says that "spellchecker" is
misspelled. :-)
--
73, Cecil http://www.w5dxp.com

C.J. as to the E layer, its effect is probably
next to nil that low in frequency, but, if memory
serves, think that there is a "D" layer, below the
"E" layer, that might have the properties you
speak of? I might have missed some, as I only
download 35 messages at a time, because of all the
junk debates (code-no code, ect). But you raise a
interesting subject as I use on 80, a G5RV, pushed
to its limits (about 15-10 feet off the ground)!
Yet I hear stations that people with higher
antennas cant hear, and it is heard better than
folks with much better antennas than this!
Frankly, this should compare to a wet noodle,
yet consistantly seems to work out to several
hundred miles at night,and on 40 during the day.
The reason it like this is NO TREES in Nevada,
and this property is on bedrock! Not saying this
is an effecient setup , just that it seems to
work! Oh well, sorry for the trouble- thought you
talking about VHF! Jim NN7K



C. J. Clegg wrote:
On Sat, 16 Dec 2006 01:22:44 +0000, Jim - NN7K wrote:

Owen is correct- and anyone operateing 10& 6
meters will tell you the same thing!

Good morning, Jim.

What I'm trying to figure out is the effect of sporadic E on the lower
bands, e.g. 75 meters.

I was on a military net on a frequency somewhat above 4 MHz and was able
to work a station 70 miles away, well after dark when the critical
frequency was below 3 MHz. According to everything I know about critical
frequencies and MUF (which isn't very much), my NVIS signal from my
17-foot-high dipole should have gone right off into space, and the
70-mile-away station shouldn't have heard a peep out of me (and vice versa).

I'm trying to figure out if the solar storms of the last few days might
have something to do with why I was able to contact that station when
every indication was I shouldn't have been able to. Sporadic E? I dunno,
maybe, but it seems like quite a stretch...