[SOC] In True SOC Style
Reicher, James
JReicher at hrblock.com
Tue Mar 6 15:16:44 EST 2007
Isn't tropospheric ducting is what happens when you use that grey
sticky-tape in the Caribbean?
73 de N8AU, Jim in Raymore, MO
Light travels faster than sound... This is why some people appear
bright until you hear them speak.
-----Original Message-----
From: soc-bounces at mailman.qth.net [mailto:soc-bounces at mailman.qth.net]
On Behalf Of Fred Jensen
Sent: Tuesday, March 06, 2007 1:48 PM
To: Second Class Operators' Club
Subject: Re: [SOC] In True SOC Style
daz at ft-817.co.uk wrote:
>
> I've heard hams talking about the grey line before.
> I thought it was the mark you get on your neck when you haven't washed
> properly.
That too, however it usually means the mark on your collar. By the time
the gray line appears there, your neck should be clean.
> You mean it has something to do with radio????
Yes. The ionosphere is divided into layers which are very creatively
name with letters. I don't know if there are A, B, and C layers, but
there are D, E, and F layers. So far, news of a G layer has not made it
out here to the American frontier that I know of. The earlier in the
alphabet, the lower the layer. The F-layer bends signals back down to
the Earth and accounts for all the distant babble we hear on 20m [and 15
and 10 if there were any spots on the sun]. It is on top and we like
it. Unfortunately, it only appears when the sun is shining on it and so
it disappears at night, accompanied by all the signals on 20.
The E-layer is similar to intelligence on TV, it comes and goes and only
appears in small places at any time, and not terribly often. When it
has come, it accounts for longer distance signals on 6m and sometimes
2m, and those ops like it a lot. The D-layer is similar to a sponge,
and it absorbs signals. The lower the frequency, the higher the
absorption. It too comes with the dawn and disappears with sunset. So,
during the day, a 160m signal gets eaten up in the D-layer, and at
night, it gets through but there is little left of the F-layer to bend
it back down. This is one reason why 160 and 80 sound fairly dead in
the daytime [the other is because I left the dummy load connected to the
radio].
At your dawn, the F-layer starts to build, and so does the D-layer, but
more slowly. I don't know why however my theory is that it is because D
is earlier in the alphabet than F and the sun starts at Z just to keep
us on our toes. Now, if it is dawn for you, it is sunset on the other
side of the planet [on most days]. There, the D-layer starts to
disappear, but for some unknown reason [OK, unknown to me] the F-layer
hangs around for a few minutes. During this time [maybe 15 - 30 min],
low frequency signals can get to the F-layer and bend down and extreme
DX is possible. Extreme antennas and extreme power help too.
I have heard this effect only once in 53 years of ham radio although I
have listened for it at least 3 or 4 times, but I am assured that it
occurs often. If you're interested, I'll be glad to make up an
explanation for tropospheric ducting too. I know it has something to do
with sticky tape.
73,
Fred K6DGW
- Northern California Contest Club
- CU in the 2007 CQP Oct 6-7
- www.cqp.org
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