Some of you may wonder how really long distance MW reception occurs,
such as the ! Kw Fresno CA station reported here in South Africa the
other day. This is a station over 10,000 miles / 16,000 km's away from
us.

Theoretically these signals take several bounces off the ionosphere to
get here, but the experts will tell you that theoretically such a low
power station over such a long distance will expend it's energy and it
is therefore not possible to receive such a long distance station even
on the most powerful receiving antenna.

However, it does happen and last year, 2007, various MW DXer's around
the world were getting very long distance DX the likes of which had
not been heard since the 80's. How is this possible then? Well, the
more scientifically minded hams that work 1.8 MHz have a theory that
these phenomenal long distance signals come in as a result of
"ducting". The theory is that the outgoing transmission goes up into
the ionosphere and gets trapped there, and then travels a considerable
distance before coming down to earth in some very far distant space.

These signals, when they arrive at the DXer's location, are usually
very faint though and may not last for more than a few seconds, or
maybe up to ten minutes if you are lucky, so you have to be very
vigilant and alert to catch something like this, but when you do =
BINGO! - extreme joy and euphoria = lovely!

Alas, this is not the sort of thing you are going to pick up in your
suburban back yard - all these catches were made by very experienced
DXer's at prime coastal DX sites using 1000ft/300m or longer
beverages. Don't worry about the radio though, anything from a Frog
(Yaesu FRG-7) will do. The important thing with IDing faint MW signals
is to have a radio that produces a good audio spectrum that catches
all the sibilants and harmonics, or otherwise you are not going to be
able to read the signal.

If you want to listen to an audio clip of my 1410 kHz CFUN Vancouver
Canada catch 10,000m/16,000km's away, go to my good DX pal Gary
Deacons website
http://www.capedx.blogspot.com/ and on the RHS you will find the audio
clip box, then search for CFUN Canada. you will see it is very faint,
but if recorded on a decent MP3 recorder you will be able to decipher
the call sign ID with a little practise and skill.

A serious DXer can always expect the unexpected

Have fun, good luck and good DX.

John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
Icom IC-7700, Icom IC-756 PRO III with MW mods
ERGO software
Drake SW8. Sangean 803A
Sony 7600D, GE SRIII, Redsun RP2100
Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270
Kiwa MW Loop.
http://www.dxing.info/about/dxers/plimmer.dx

wrote:

Some of you may wonder how really long distance MW reception occurs,
such as the ! Kw Fresno CA station reported here in South Africa the
other day. This is a station over 10,000 miles / 16,000 km's away from
us.

Theoretically these signals take several bounces off the ionosphere to
get here, but the experts will tell you that theoretically such a low
power station over such a long distance will expend it's energy and it
is therefore not possible to receive such a long distance station even
on the most powerful receiving antenna.

However, it does happen and last year, 2007, various MW DXer's around
the world were getting very long distance DX the likes of which had
not been heard since the 80's. How is this possible then? Well, the
more scientifically minded hams that work 1.8 MHz have a theory that
these phenomenal long distance signals come in as a result of
"ducting". The theory is that the outgoing transmission goes up into
the ionosphere and gets trapped there, and then travels a considerable
distance before coming down to earth in some very far distant space.

That theory was expounded upon by I think John Bryant and another fellow in one
of Fine Tunings Procedings issues (sorry, I no longer have them) back in the
late 80's or early 90's.

I've not believed in radio signals making 'hops' for a very long time as it
simply does not make sense.



These signals, when they arrive at the DXer's location, are usually
very faint though and may not last for more than a few seconds, or
maybe up to ten minutes if you are lucky, so you have to be very
vigilant and alert to catch something like this, but when you do =
BINGO! - extreme joy and euphoria = lovely!

Alas, this is not the sort of thing you are going to pick up in your
suburban back yard - all these catches were made by very experienced
DXer's at prime coastal DX sites using 1000ft/300m or longer
beverages. Don't worry about the radio though, anything from a Frog
(Yaesu FRG-7) will do. The important thing with IDing faint MW signals
is to have a radio that produces a good audio spectrum that catches
all the sibilants and harmonics, or otherwise you are not going to be
able to read the signal.

If you want to listen to an audio clip of my 1410 kHz CFUN Vancouver
Canada catch 10,000m/16,000km's away, go to my good DX pal Gary
Deacons website
http://www.capedx.blogspot.com/ and on the RHS you will find the audio
clip box, then search for CFUN Canada. you will see it is very faint,
but if recorded on a decent MP3 recorder you will be able to decipher
the call sign ID with a little practise and skill.

A serious DXer can always expect the unexpected

Have fun, good luck and good DX.

John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
Icom IC-7700, Icom IC-756 PRO III with MW mods
ERGO software
Drake SW8. Sangean 803A
Sony 7600D, GE SRIII, Redsun RP2100
Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270
Kiwa MW Loop.
http://www.dxing.info/about/dxers/plimmer.dx

On 23 Jul, 16:49, wrote:
Some of you may wonder how really long distance MW reception occurs,
such as the ! Kw Fresno CA station reported here in South Africa the
other day. This is a station over 10,000 miles / 16,000 km's away from
us.

Theoretically these signals take several bounces off the ionosphere to
get here, but the experts will tell you that theoretically such a low
power station over such a long distance will expend it's energy and it
is therefore not possible to receive such a long distance station even
on the most powerful receiving antenna.

However, it does happen and last year, 2007, various MW DXer's around
the world were getting very long distance DX the likes of which had
not been heard since the 80's. How is this possible then? Well, the
more scientifically minded hams that work 1.8 MHz have a theory that
these phenomenal long distance signals come in as a result of
"ducting". The theory is that the outgoing transmission goes up into
the ionosphere and gets trapped there, and then travels a considerable
distance before coming down to earth in some very far distant space.

These signals, when they arrive at the DXer's location, are usually
very faint though and may not last for more than a few seconds, or
maybe up to ten minutes if you are lucky, so you have to be very
vigilant and alert to catch something like this, but when you do =
BINGO! - extreme joy and euphoria = lovely!

Alas, this is not the sort of thing you are going to pick up in your
suburban back yard - all these catches were made by very experienced
DXer's at prime coastal DX sites using 1000ft/300m or longer
beverages. Don't worry about the radio though, anything from a Frog
(Yaesu FRG-7) will do. The important thing with IDing faint MW signals
is to have a radio that produces a good audio spectrum that catches
all the sibilants and harmonics, or otherwise you are not going to be
able to read the signal.

If you want to listen to an audio clip of my 1410 kHz CFUN Vancouver
Canada catch 10,000m/16,000km's away, go to my good DX pal Gary
Deacons websitehttp://www.capedx.blogspot.com/and on the RHS you will find the audio
clip box, then search for CFUN Canada. you will see it is very faint,
but if recorded on a decent MP3 recorder you will be able to decipher
the call sign ID with a little practise and skill.

A serious DXer can always expect the unexpected

Have fun, good luck and good DX.

John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
Icom IC-7700, Icom IC-756 PRO III with MW mods
ERGO software
Drake SW8. Sangean 803A
Sony 7600D, GE SRIII, Redsun RP2100
Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270
Kiwa MW Loop.http://www.dxing.info/about/dxers/plimmer.dx

"don't worry about the radio though"... I beg to disagree. Yes, the
FRG-7 would work well in an RF-free environment like that of SA, but
not in Europe or USA. I've had one. I do agree though, that there are
signals that will only be audible seconds or minutes and one will have
to wait years, or forever, to hear them again.
The interesting thing is that with the advent of SDR, many more
"impossible" stations have been heard. At least that is the experience
from the Nordic countries the past winter. There are many stations
visiting our antennas we never hear.
BM

On Jul 23, 10:46*pm, bm wrote:
"don't worry about the radio though"... I beg to disagree. Yes, the
FRG-7 would work well in an RF-free environment like that of SA, but
not in Europe or USA. I've had one. I do agree though, that there are
signals that will only be audible seconds or minutes and one will have
to wait years, or forever, to hear them again.
The interesting thing is that with the advent of SDR, many more
"impossible" stations have been heard. At least that is the experience
from the Nordic countries the past winter. There are many stations
visiting our antennas we never hear.
BM-

Well said Bjarne - you are right of course - the SDR radio's have
indeed lifted the hobby to another higher level. The statement I made
was rather not to discourage budding MW DXer's to give it a go, even
if they don't have the best equipment available.

However John Bryant did get his amazing catches on an E1 portable and
to see my pal Gary Deacon operate his FRG-7 is an eye opener,
although, admittedly, conditions in S.A. are more favourable as you
say.

I myself am a firm believer if DXing is your lifelong hobby and gives
you lots of enjoyment and satisfaction, then you should spend as much
on the best equipment that you can afford. I have not stinted on
getting the best radio's available for my enjoyment and fun.

Undoubtedly though, using an SDR that is recording a whopping 800 kHz
of bandwidth at the TOH must always achieve much better results than a
conventional radio that can only listen on one frequency at a time.

JP

On Jul 23, 4:52*pm, dxAce wrote:
That theory was expounded upon by I think John Bryant and another fellow in one
of Fine Tunings Procedings issues (sorry, I no longer have them) back in the
late 80's or early 90's.

I've not believed in radio signals making 'hops' for a very long time as it
simply does not make sense.

Yes indeed Prof. John Bryant does expound this view (ducting), but I
don't think he invented the theory.

It was expounded a long time ago by the 160m hams in ON4UN John
Devoldere's book "Low -Band DXing"

JP

John's fantastic catches on his Eton E1 were of course from Easter Island, a
place with a rather unoccupied MW radio dial! Not too much QRM or adjacent
channel splatter there, and the E1 was more than enough receiver for the
task.

BTW, John's co-author in his Proceedings articles about propagation was
David Clark of Ontario, Canada. Now *that's* someone I wish would get back
into the DXing hobby. I enjoyed his occasional visits and attendance at the
Grayland DXpeditions.

73,

Guy Atkins
Puyallup, WA USA
www.perseus-sdr.blogspot.com


wrote in message
...
On Jul 23, 10:46 pm, bm wrote:
"don't worry about the radio though"... I beg to disagree. Yes, the
FRG-7 would work well in an RF-free environment like that of SA, but
not in Europe or USA. I've had one. I do agree though, that there are
signals that will only be audible seconds or minutes and one will have
to wait years, or forever, to hear them again.
The interesting thing is that with the advent of SDR, many more
"impossible" stations have been heard. At least that is the experience
from the Nordic countries the past winter. There are many stations
visiting our antennas we never hear.
BM-

Well said Bjarne - you are right of course - the SDR radio's have
indeed lifted the hobby to another higher level. The statement I made
was rather not to discourage budding MW DXer's to give it a go, even
if they don't have the best equipment available.

However John Bryant did get his amazing catches on an E1 portable and
to see my pal Gary Deacon operate his FRG-7 is an eye opener,
although, admittedly, conditions in S.A. are more favourable as you
say.

I myself am a firm believer if DXing is your lifelong hobby and gives
you lots of enjoyment and satisfaction, then you should spend as much
on the best equipment that you can afford. I have not stinted on
getting the best radio's available for my enjoyment and fun.

Undoubtedly though, using an SDR that is recording a whopping 800 kHz
of bandwidth at the TOH must always achieve much better results than a
conventional radio that can only listen on one frequency at a time.

JP

wrote in news:53e735f2-a5d3-48c0-b824-f9588a57acf1
@z72g2000hsb.googlegroups.com:

Well, the
more scientifically minded hams that work 1.8 MHz have a theory that
these phenomenal long distance signals come in as a result of
"ducting". The theory is that the outgoing transmission goes up into
the ionosphere and gets trapped there, and then travels a considerable
distance before coming down to earth in some very far distant space.


I have had an extraordinary experience with ducting.

This was back in the early 1990s. I lived in SW VA then. Driving home one
midday, I saw an unmistakable squall line approching, which signaled the
advance of a cold front. It was winter, so there was no lightning.

For some reason, I raced into the house and fired up the MW DX rig.

Within minutes, my local stations were replaced by exotic skip stations
in the Far South. Georgia, Alabama, Missisippi, even Louisiana. This
lasted all of ten minutes. I logged as many of them as I could.

On another winter day a few years later, I was hearing stations from the
northeast in midday that I could only usually hear at night. All the NYC
stations booming in, WWKB, CHUM, etc. This lasted a bit longer, maybe an
hour.

In both cases, the effect was because of a weather front, and the effect
was less than 1000 miles.