|
Some excellent long haul beacons on 10GHz again this morning , with band still well open across to EU from here in IO80 till 09.30 UTC . I was walking along the prom at Bournemouth looking at the 6 large cruise ships anchored in the bay , including the Arora , the largest in the World , when I noticed a distinct brown smear across almost a full 90 degree arc .This slowly lifted and went at 12.30 ish . It makes me consider if the prospects for more Tropo this late Sept/October are good , with the large reduction in high level man made clag . Probably just the fading memories of an old G8 + 3 callsign , when 144/432MHz DX was a regular Autumnal event....
73 John G0API/G8MCP
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Dave
Hello John, Thanks for your comments. I was pretty pessimistic at working anything today as I was outside the main ducting area. Anyway I went out for 10 pm last night and immmediatly started hearing interesting beacons. I went to the higher car park at 400m asl at Haytor as I was aware how difficult the path is for me to get to the east coast. The problem seems to be the Black Down Hills. There I was hearing GB3PKT, GB3SEE and GB3LEX all night. I heard lots of PI beacons ,ON ,two F several DB and three of the OZ beacons throughout the night,which fluctuated in strength . I did manage a QSO with OZ1 FF at 0645Z but I wasn’t able to contact people to work in the middle of the night ,predictably. Like you I could see a high level inversion later, which persisted until beyond mid afternoon. What an amazing night and morning. Exciting stuff for 10ghz. Best wishes,
On 21 Sep 2020, at 20:54, John Fell <john.g0api@...> wrote:
Some excellent long haul beacons on 10GHz again this morning , with band still well open across to EU from here in IO80 till 09.30 UTC . I was walking along the prom at Bournemouth looking at the 6 large cruise ships anchored in the bay , including the Arora , the largest in the World , when I noticed a distinct brown smear across almost a full 90 degree arc .This slowly lifted and went at 12.30 ish . It makes me consider if the prospects for more Tropo this late Sept/October are good , with the large reduction in high level man made clag . Probably just the fading memories of an old G8 + 3 callsign , when 144/432MHz DX was a regular Autumnal event....
73 John G0API/G8MCP
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|
|
Hi Dave , I was very impressed to see your recent Beacon Spots and did actually visualise Hay Tor ! Been a long time since we (G4RFR/P) activated Oakment Hill on the North side , but Iguess that would have had some strong signals to the East . Typically it all seems very flat so far this evening and RS is the probable mechanism for the next few days .
73 John G0API
Hello John, Thanks for your comments. I was pretty pessimistic at working anything today as I was outside the main ducting area. Anyway I went out for 10 pm last night and immmediatly started hearing interesting beacons. I went to the higher car park at 400m asl at Haytor as I was aware how difficult the path is for me to get to the east coast. The problem seems to be the Black Down Hills. There I was hearing GB3PKT, GB3SEE and GB3LEX all night. I heard lots of PI beacons ,ON ,two F several DB and three of the OZ beacons throughout the night,which fluctuated in strength . I did manage a QSO with OZ1 FF at 0645Z but I wasn’t able to contact people to work in the middle of the night ,predictably. Like you I could see a high level inversion later, which persisted until beyond mid afternoon. What an amazing night and morning. Exciting stuff for 10ghz. Best wishes, David G4GLT. Some excellent long haul beacons on 10GHz again this morning , with band still well open across to EU from here in IO80 till 09.30 UTC . I was walking along the prom at Bournemouth looking at the 6 large cruise ships anchored in the bay , including the Arora , the largest in the World , when I noticed a distinct brown smear across almost a full 90 degree arc .This slowly lifted and went at 12.30 ish . It makes me consider if the prospects for more Tropo this late Sept/October are good , with the large reduction in high level man made clag . Probably just the fading memories of an old G8 + 3 callsign , when 144/432MHz DX was a regular Autumnal event....
73 John G0API/G8MCP
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|
For the first time in weeks, I can't hear even a faint sniff from
GB3OSW, and KBQ is absent as well. I can decode GB3PKT on
averaging at -19dB, but other than CAM and obviously FNY, things
are very flat. Last night I was hearing OZ5SHF and DB0GHZ very
well, but nothing much inland in PA. PA0O/b was a nice signal for
200mW in JO33, and F5ZTR was romping in for several hours along
with F1BQ through some of my trees. No actual humans about at
that time of night. DB0GHZ is still there at S2 or so now. It is
behind a 600ft hill, so not exactly an optimal path from here.
Neil G4DBN
On 21/09/2020 22:38, John Fell wrote:
Hi Dave ,
I was very impressed to see your recent Beacon Spots and
did actually visualise Hay Tor !
Been a long time since we (G4RFR/P) activated Oakment Hill
on the North side , but Iguess that would have had some strong
signals to the East .
Typically it all seems very flat so far this evening and RS
is the probable mechanism for the next few days .
73
John
G0API
Hello John,
Thanks for your comments. I was pretty pessimistic at
working anything today as I was outside the main ducting
area. Anyway I went out for 10 pm last night and
immmediatly started hearing interesting beacons. I went to
the higher car park at 400m asl at Haytor as I was aware
how difficult the path is for me to get to the east coast.
The problem seems to be the Black Down Hills. There I was
hearing GB3PKT, GB3SEE and GB3LEX all night. I heard lots
of PI beacons ,ON ,two F several DB and three of the OZ
beacons throughout the night,which fluctuated in strength
. I did manage a QSO with OZ1 FF at 0645Z but I wasn’t
able to contact people to work in the middle of the night
,predictably. Like you I could see a high level inversion
later, which persisted until beyond mid afternoon. What an
amazing night and morning. Exciting stuff for 10ghz.
Best wishes,
David G4GLT.
Some excellent long haul beacons on
10GHz again this morning , with band still well open
across to EU from here in IO80 till 09.30 UTC .
I was walking along the prom at Bournemouth
looking at the 6 large cruise ships anchored in
the bay , including the Arora , the largest in the
World , when I noticed a distinct brown smear
across almost a full 90 degree arc .This slowly
lifted and went at 12.30 ish .
It makes me consider if the prospects for more
Tropo this late Sept/October are good , with the
large reduction in high level man made clag .
Probably just the fading memories of an old
G8 + 3 callsign , when 144/432MHz DX was a regular
Autumnal event....
73
John
G0API/G8MCP
--
Neil
http://g4dbn.uk
|
|
|
Super tropo as seen here near the East coast. Lots of beacons and
some nice DX contacts. The SK1SHH (JO97CJ) beacon was heard on
10GHz during the morning up to 529, distance 1234km, and signals
exchanged with SM1HOW (JO97GL) but QSB prevented a QSO. Signals to
the Stockholm area increased during the evening, an initial test
at 17:40 with SK0EN (JO99JX) resulted in a good 23cm QSO but nil
on 6cm. We tried again around 20:00z and exchanged 579 on 5760MHz,
and then QSYd to 3cm, where signals were 529 each way after
aligning antennas, and came up to S5 by the end when we exchanged
a few words on SSB. Distance from here to SK0EN is 1395km, my best
DX on these two bands to date. I also worked SM7GEP (JO77IP) on
3cm at 1058km.
73
John G3XDY
On 21/09/2020 22:05, Neil Smith G4DBN
wrote:
For the first time in weeks, I can't hear even a faint sniff
from GB3OSW, and KBQ is absent as well. I can decode GB3PKT on
averaging at -19dB, but other than CAM and obviously FNY, things
are very flat. Last night I was hearing OZ5SHF and DB0GHZ very
well, but nothing much inland in PA. PA0O/b was a nice signal
for 200mW in JO33, and F5ZTR was romping in for several hours
along with F1BQ through some of my trees. No actual humans
about at that time of night. DB0GHZ is still there at S2 or so
now. It is behind a 600ft hill, so not exactly an optimal path
from here.
Neil G4DBN
On 21/09/2020 22:38, John Fell wrote:
Hi Dave ,
I was very impressed to see your recent Beacon Spots and
did actually visualise Hay Tor !
Been a long time since we (G4RFR/P) activated Oakment
Hill on the North side , but Iguess that would have had some
strong signals to the East .
Typically it all seems very flat so far this evening and
RS is the probable mechanism for the next few days .
73
John
G0API
Hello John,
Thanks for your comments. I was pretty pessimistic at
working anything today as I was outside the main ducting
area. Anyway I went out for 10 pm last night and
immmediatly started hearing interesting beacons. I went
to the higher car park at 400m asl at Haytor as I was
aware how difficult the path is for me to get to the
east coast. The problem seems to be the Black Down
Hills. There I was hearing GB3PKT, GB3SEE and GB3LEX all
night. I heard lots of PI beacons ,ON ,two F several DB
and three of the OZ beacons throughout the night,which
fluctuated in strength . I did manage a QSO with OZ1 FF
at 0645Z but I wasn’t able to contact people to work in
the middle of the night ,predictably. Like you I could
see a high level inversion later, which persisted until
beyond mid afternoon. What an amazing night and morning.
Exciting stuff for 10ghz.
Best wishes,
David G4GLT.
Some excellent long haul beacons on
10GHz again this morning , with band still well
open across to EU from here in IO80 till 09.30 UTC
.
I was walking along the prom at Bournemouth
looking at the 6 large cruise ships anchored in
the bay , including the Arora , the largest in
the World , when I noticed a distinct brown
smear across almost a full 90 degree arc .This
slowly lifted and went at 12.30 ish .
It makes me consider if the prospects for
more Tropo this late Sept/October are good ,
with the large reduction in high level man made
clag .
Probably just the fading memories of an old
G8 + 3 callsign , when 144/432MHz DX was a
regular Autumnal event....
73
John
G0API/G8MCP
--
Neil
http://g4dbn.uk
|
|
|
That tropo was good fun – as well as being a bit frustrating at times ! In addition to the Scandinavian tropo already noted, I was very pleased to work up to IO86, IO87 and IO97 from JO01. One thing I need help in understanding; On Sunday evening, there were some very skew paths across the North Sea, For example, the strongest signal from SM6VTZ on 23cms was when I beamed at about 80 degrees. The direct path is at 40 degrees. When we QSY’d to 3cms, only the direct path was viable. How does that work ? John G4ZTR
From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of John Quarmby via groups.io
Sent: 22 September 2020 00:37
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo Super tropo as seen here near the East coast. Lots of beacons and some nice DX contacts. The SK1SHH (JO97CJ) beacon was heard on 10GHz during the morning up to 529, distance 1234km, and signals exchanged with SM1HOW (JO97GL) but QSB prevented a QSO. Signals to the Stockholm area increased during the evening, an initial test at 17:40 with SK0EN (JO99JX) resulted in a good 23cm QSO but nil on 6cm. We tried again around 20:00z and exchanged 579 on 5760MHz, and then QSYd to 3cm, where signals were 529 each way after aligning antennas, and came up to S5 by the end when we exchanged a few words on SSB. Distance from here to SK0EN is 1395km, my best DX on these two bands to date. I also worked SM7GEP (JO77IP) on 3cm at 1058km. 73 John G3XDY On 21/09/2020 22:05, Neil Smith G4DBN wrote: For the first time in weeks, I can't hear even a faint sniff from GB3OSW, and KBQ is absent as well. I can decode GB3PKT on averaging at -19dB, but other than CAM and obviously FNY, things are very flat. Last night I was hearing OZ5SHF and DB0GHZ very well, but nothing much inland in PA. PA0O/b was a nice signal for 200mW in JO33, and F5ZTR was romping in for several hours along with F1BQ through some of my trees. No actual humans about at that time of night. DB0GHZ is still there at S2 or so now. It is behind a 600ft hill, so not exactly an optimal path from here. Neil G4DBN On 21/09/2020 22:38, John Fell wrote: Hi Dave , I was very impressed to see your recent Beacon Spots and did actually visualise Hay Tor ! Been a long time since we (G4RFR/P) activated Oakment Hill on the North side , but Iguess that would have had some strong signals to the East . Typically it all seems very flat so far this evening and RS is the probable mechanism for the next few days . Hello John, Thanks for your comments. I was pretty pessimistic at working anything today as I was outside the main ducting area. Anyway I went out for 10 pm last night and immmediatly started hearing interesting beacons. I went to the higher car park at 400m asl at Haytor as I was aware how difficult the path is for me to get to the east coast. The problem seems to be the Black Down Hills. There I was hearing GB3PKT, GB3SEE and GB3LEX all night. I heard lots of PI beacons ,ON ,two F several DB and three of the OZ beacons throughout the night,which fluctuated in strength . I did manage a QSO with OZ1 FF at 0645Z but I wasn’t able to contact people to work in the middle of the night ,predictably. Like you I could see a high level inversion later, which persisted until beyond mid afternoon. What an amazing night and morning. Exciting stuff for 10ghz. David G4GLT. Some excellent long haul beacons on 10GHz again this morning , with band still well open across to EU from here in IO80 till 09.30 UTC . I was walking along the prom at Bournemouth looking at the 6 large cruise ships anchored in the bay , including the Arora , the largest in the World , when I noticed a distinct brown smear across almost a full 90 degree arc .This slowly lifted and went at 12.30 ish . It makes me consider if the prospects for more Tropo this late Sept/October are good , with the large reduction in high level man made clag . Probably just the fading memories of an old G8 + 3 callsign , when 144/432MHz DX was a regular Autumnal event....
-- Neil http://g4dbn.uk
|
|
|
Whilst at least one well-known propagation pundit reckons it is due to vertical incidence refraction out over the North Sea, I think it is far more likely reflections from structures on the opposite coastline. There is certainly a strong body of evidence for vertical incidence, such as outflow from the Rhine etc, radar reflections are also a well known and used propagation mode. Until we have beacons with suitable modulation modes/time to measure time of flight, I guess we will continue to guess at the propagation mode. Wider bandwidths, using SDR receivers, should make this feasible.
73 de Sam, G4DDK
toggle quoted messageShow quoted text
------ Original Message ------
From: "John Lemay" <john@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 08:14
Subject: Re: [UKMicrowaves] Tropo
That tropo was good fun – as well as being a bit frustrating at times ! In addition to the Scandinavian tropo already noted, I was very pleased to work up to IO86, IO87 and IO97 from JO01. One thing I need help in understanding; On Sunday evening, there were some very skew paths across the North Sea, For example, the strongest signal from SM6VTZ on 23cms was when I beamed at about 80 degrees. The direct path is at 40 degrees. When we QSY’d to 3cms, only the direct path was viable. How does that work ? John G4ZTR Fromded: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of John Quarmby via groups.io
Sent: 22 September 2020 00:37
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo Super tropo as seen here near the East coast. Lots of beacons and some nice DX contacts. The SK1SHH (JO97CJ) beacon was heard on 10GHz during the morning up to 529, distance 1234km, and signals exchanged with SM1HOW (JO97GL) but QSB prevented a QSO. Signals to the Stockholm area increased during the evening, an initial test at 17:40 with SK0EN (JO99JX) resulted in a good 23cm QSO but nil on 6cm. We tried again around 20:00z and exchanged 579 on 5760MHz, and then QSYd to 3cm, where signals were 529 each way after aligning antennas, and came up to S5 by the end when we exchanged a few words on SSB. Distance from here to SK0EN is 1395km, my best DX on these two bands to date. I also worked SM7GEP (JO77IP) on 3cm at 1058km. 73 John G3XDY On 21/09/2020 22:05, Neil Smith G4DBN wrote: For the first time in weeks, I can't hear even a faint sniff from GB3OSW, and KBQ is absent as well. I can decode GB3PKT on averaging at -19dB, but other than CAM and obviously FNY, things are very flat. Last night I was hearing OZ5SHF and DB0GHZ very well, but nothing much inland in PA. PA0O/b was a nice signal for 200mW in JO33, and F5ZTR was romping in for several hours along with F1BQ through some of my trees. No actual humans about at that time of night. DB0GHZ is still there at S2 or so now. It is behind a 600ft hill, so not exactly an optimal path from here. Neil G4DBN On 21/09/2020 22:38, John Fell wrote: Hi Dave , I was very impressed to see your recent Beacon Spots and did actually visualise Hay Tor ! Been a long time since we (G4RFR/P) activated Oakment Hill on the North side , but Iguess that would have had some strong signals to the East . Typically it all seems very flat so far this evening and RS is the probable mechanism for the next few days . Hello John, Thanks for your comments. I was pretty pessimistic at working anything today as I was outside the main ducting area. Anyway I went out for 10 pm last night and immmediatly started hearing interesting beacons. I went to the higher car park at 400m asl at Haytor as I was aware how difficult the path is for me to get to the east coast. The problem seems to be the Black Down Hills. There I was hearing GB3PKT, GB3SEE and GB3LEX all night. I heard lots of PI beacons ,ON ,two F several DB and three of the OZ beacons throughout the night,which fluctuated in strength . I did manage a QSO with OZ1 FF at 0645Z but I wasn’t able to contact people to work in the middle of the night ,predictably. Like you I could see a high level inversion later, which persisted until beyond mid afternoon. What an amazing night and morning. Exciting stuff for 10ghz. David G4GLT. Some excellent long haul beacons on 10GHz again this morning , with band still well open across to EU from here in IO80 till 09.30 UTC . I was walking along the prom at Bournemouth looking at the 6 large cruise ships anchored in the bay , including the Arora , the largest in the World , when I noticed a distinct brown smear across almost a full 90 degree arc .This slowly lifted and went at 12.30 ish . It makes me consider if the prospects for more Tropo this late Sept/October are good , with the large reduction in high level man made clag . Probably just the fading memories of an old G8 + 3 callsign , when 144/432MHz DX was a regular Autumnal event....
-- Neil http://g4dbn.uk
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Similarly heard MCB on 23cm from 100 degrees as well as direct NE. Surprised because 100 degrees from my qth on the Lizard is straight out across the sea, a lot further before you meet anything compared to the direct path. I surmised either
a reflection from something in South Devon or a ship in the Channel. The path disappeared after a few days so I feel it may have been an anchored ship.
Paul
Sent from my Samsung Galaxy smartphone.
toggle quoted messageShow quoted text
-------- Original message --------
From: "SAM JEWELL via groups.io" <jewell@...>
Date: 22/09/2020 08:42 (GMT+00:00)
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo
Whilst at least one well-known propagation pundit reckons it is due to vertical incidence refraction out over the North Sea, I think it is far more likely reflections from structures on the opposite coastline. There is certainly a strong body of evidence for
vertical incidence, such as outflow from the Rhine etc, radar reflections are also a well known and used propagation mode.
Until we have beacons with suitable modulation modes/time to measure time of flight, I guess we will continue to guess at the propagation mode.
Wider bandwidths, using SDR receivers, should make this feasible.
73 de Sam, G4DDK
------ Original Message ------
From: "John Lemay" <john@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 08:14
Subject: Re: [UKMicrowaves] Tropo
That tropo was good fun – as well as being a bit frustrating at times !
In addition to the Scandinavian tropo already noted, I was very pleased to work up to IO86, IO87 and IO97 from JO01.
One thing I need help in understanding; On Sunday evening, there were some very skew paths across the North Sea, For example, the strongest signal from
SM6VTZ on 23cms was when I beamed at about 80 degrees. The direct path is at 40 degrees. When we QSY’d to 3cms, only the direct path was viable. How does that work ?
John G4ZTR
Fromded:
UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io]
On Behalf Of John Quarmby via groups.io
Sent: 22 September 2020 00:37
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo
Super tropo as seen here near the East coast. Lots of beacons and some nice DX contacts. The SK1SHH (JO97CJ) beacon was heard on 10GHz during the morning up to 529, distance 1234km, and signals exchanged with SM1HOW (JO97GL) but QSB prevented a QSO. Signals
to the Stockholm area increased during the evening, an initial test at 17:40 with SK0EN (JO99JX) resulted in a good 23cm QSO but nil on 6cm. We tried again around 20:00z and exchanged 579 on 5760MHz, and then QSYd to 3cm, where signals were 529 each way after
aligning antennas, and came up to S5 by the end when we exchanged a few words on SSB. Distance from here to SK0EN is 1395km, my best DX on these two bands to date. I also worked SM7GEP (JO77IP) on 3cm at 1058km.
73
John G3XDY
On 21/09/2020 22:05, Neil Smith G4DBN wrote:
For the first time in weeks, I can't hear even a faint sniff from GB3OSW, and KBQ is absent as well. I can decode GB3PKT on averaging at -19dB, but other than CAM and obviously FNY, things are very flat. Last night I was hearing OZ5SHF and DB0GHZ very well,
but nothing much inland in PA. PA0O/b was a nice signal for 200mW in JO33, and F5ZTR was romping in for several hours along with F1BQ through some of my trees. No actual humans about at that time of night. DB0GHZ is still there at S2 or so now. It is behind
a 600ft hill, so not exactly an optimal path from here.
Neil G4DBN
On 21/09/2020 22:38, John Fell wrote:
Hi Dave ,
I was very impressed to see your recent Beacon Spots and did actually visualise Hay Tor !
Been a long time since we (G4RFR/P) activated Oakment Hill on the North side , but Iguess that would have had some strong signals to the East .
Typically it all seems very flat so far this evening and RS is the probable mechanism for the next few days .
Hello John,
Thanks for your comments. I was pretty pessimistic at working anything today as I was outside the main ducting area. Anyway I went out for 10 pm last night and immmediatly started hearing interesting beacons. I went to the higher car park
at 400m asl at Haytor as I was aware how difficult the path is for me to get to the east coast. The problem seems to be the Black Down Hills. There I was hearing GB3PKT, GB3SEE and GB3LEX all night. I heard lots of PI beacons ,ON ,two F several DB and three
of the OZ beacons throughout the night,which fluctuated in strength . I did manage a QSO with OZ1 FF at 0645Z but I wasn’t able to contact people to work in the middle of the night ,predictably. Like you I could see a high level inversion later, which persisted
until beyond mid afternoon. What an amazing night and morning. Exciting stuff for 10ghz.
David G4GLT.
Some excellent long haul beacons on 10GHz again this morning , with band still well open across to EU from here in IO80 till 09.30 UTC .
I was walking along the prom at Bournemouth looking at the 6 large cruise ships anchored in the bay , including the Arora , the largest in the World , when I noticed a distinct brown smear across almost a full 90 degree arc .This slowly
lifted and went at 12.30 ish .
It makes me consider if the prospects for more Tropo this late Sept/October are good , with the large reduction in high level man made clag .
Probably just the fading memories of an old G8 + 3 callsign , when 144/432MHz DX was a regular Autumnal event....
--
Neil
http://g4dbn.uk
|
|
|
“Ship-scatter” …. got to be careful how you say that !. That could work. Beaming east from here Harwich/Felixstowe is about 30km and a fully laden container ship is a sizeable reflecting lump. But these skew paths only happen from time to time, coincident with tropo (as far as I can tell). John G4ZTR
From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Paul Randall G3NJV
Sent: 22 September 2020 09:00
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo Similarly heard MCB on 23cm from 100 degrees as well as direct NE. Surprised because 100 degrees from my qth on the Lizard is straight out across the sea, a lot further before you meet anything compared to the direct path. I surmised either a reflection from something in South Devon or a ship in the Channel. The path disappeared after a few days so I feel it may have been an anchored ship. Sent from my Samsung Galaxy smartphone. -------- Original message -------- From: "SAM JEWELL via groups.io" <jewell@...> Date: 22/09/2020 08:42 (GMT+00:00) To: UKMicrowaves@groups.io Subject: Re: [UKMicrowaves] Tropo
Whilst at least one well-known propagation pundit reckons it is due to vertical incidence refraction out over the North Sea, I think it is far more likely reflections from structures on the opposite coastline. There is certainly a strong body of evidence for vertical incidence, such as outflow from the Rhine etc, radar reflections are also a well known and used propagation mode.
Until we have beacons with suitable modulation modes/time to measure time of flight, I guess we will continue to guess at the propagation mode. Wider bandwidths, using SDR receivers, should make this feasible.
------ Original Message ------
From: "John Lemay" <john@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 08:14
Subject: Re: [UKMicrowaves] Tropo
That tropo was good fun – as well as being a bit frustrating at times ! In addition to the Scandinavian tropo already noted, I was very pleased to work up to IO86, IO87 and IO97 from JO01. One thing I need help in understanding; On Sunday evening, there were some very skew paths across the North Sea, For example, the strongest signal from SM6VTZ on 23cms was when I beamed at about 80 degrees. The direct path is at 40 degrees. When we QSY’d to 3cms, only the direct path was viable. How does that work ? John G4ZTR Fromded: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of John Quarmby via groups.io
Sent: 22 September 2020 00:37
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo Super tropo as seen here near the East coast. Lots of beacons and some nice DX contacts. The SK1SHH (JO97CJ) beacon was heard on 10GHz during the morning up to 529, distance 1234km, and signals exchanged with SM1HOW (JO97GL) but QSB prevented a QSO. Signals to the Stockholm area increased during the evening, an initial test at 17:40 with SK0EN (JO99JX) resulted in a good 23cm QSO but nil on 6cm. We tried again around 20:00z and exchanged 579 on 5760MHz, and then QSYd to 3cm, where signals were 529 each way after aligning antennas, and came up to S5 by the end when we exchanged a few words on SSB. Distance from here to SK0EN is 1395km, my best DX on these two bands to date. I also worked SM7GEP (JO77IP) on 3cm at 1058km. 73 John G3XDY On 21/09/2020 22:05, Neil Smith G4DBN wrote: For the first time in weeks, I can't hear even a faint sniff from GB3OSW, and KBQ is absent as well. I can decode GB3PKT on averaging at -19dB, but other than CAM and obviously FNY, things are very flat. Last night I was hearing OZ5SHF and DB0GHZ very well, but nothing much inland in PA. PA0O/b was a nice signal for 200mW in JO33, and F5ZTR was romping in for several hours along with F1BQ through some of my trees. No actual humans about at that time of night. DB0GHZ is still there at S2 or so now. It is behind a 600ft hill, so not exactly an optimal path from here. Neil G4DBN On 21/09/2020 22:38, John Fell wrote: Hi Dave , I was very impressed to see your recent Beacon Spots and did actually visualise Hay Tor ! Been a long time since we (G4RFR/P) activated Oakment Hill on the North side , but Iguess that would have had some strong signals to the East . Typically it all seems very flat so far this evening and RS is the probable mechanism for the next few days . Hello John, Thanks for your comments. I was pretty pessimistic at working anything today as I was outside the main ducting area. Anyway I went out for 10 pm last night and immmediatly started hearing interesting beacons. I went to the higher car park at 400m asl at Haytor as I was aware how difficult the path is for me to get to the east coast. The problem seems to be the Black Down Hills. There I was hearing GB3PKT, GB3SEE and GB3LEX all night. I heard lots of PI beacons ,ON ,two F several DB and three of the OZ beacons throughout the night,which fluctuated in strength . I did manage a QSO with OZ1 FF at 0645Z but I wasn’t able to contact people to work in the middle of the night ,predictably. Like you I could see a high level inversion later, which persisted until beyond mid afternoon. What an amazing night and morning. Exciting stuff for 10ghz. David G4GLT. Some excellent long haul beacons on 10GHz again this morning , with band still well open across to EU from here in IO80 till 09.30 UTC . I was walking along the prom at Bournemouth looking at the 6 large cruise ships anchored in the bay , including the Arora , the largest in the World , when I noticed a distinct brown smear across almost a full 90 degree arc .This slowly lifted and went at 12.30 ish . It makes me consider if the prospects for more Tropo this late Sept/October are good , with the large reduction in high level man made clag . Probably just the fading memories of an old G8 + 3 callsign , when 144/432MHz DX was a regular Autumnal event....
-- Neil http://g4dbn.uk
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|
|
I often get skew and duplicate paths from DB0GHZ, with two peaks
around 5-10 degrees apart, and sometimes there is no direct signal
and the skew can be 30 degrees or more. There isn't anything much
to reflect off other than perhaps Denmark, but then I'd expect to
see OZ beacons as well.
Perhaps we should be looking to fund chirped beacons with very
tight GPS time-sync for time-of-flight analysis? On a straight
path with around 2 milliseconds of delay, what sort of chirp or
sequence timing would be needed to get enough resolution? Would
the necessary bandwidth be licenceable? If not, perhaps an
alternative would be a network of strategically-placed
reverse-beacon receivers with GPS sync, used to receive attended
transmissions from home stations in a similar approach to the
ADS-B receive network?
Neil
toggle quoted messageShow quoted text
On 22/09/2020 10:22, John Lemay wrote:
“Ship-scatter”
…. got to be careful how you say that !.
That
could work. Beaming east from here Harwich/Felixstowe is
about 30km and a fully laden container ship is a sizeable
reflecting lump. But these skew paths only happen from time
to time, coincident with tropo (as far as I can tell).
John
G4ZTR
Similarly heard MCB on 23cm from 100
degrees as well as direct NE. Surprised because 100 degrees
from my qth on the Lizard is straight out across the sea, a
lot further before you meet anything compared to the direct
path. I surmised either a reflection from something in South
Devon or a ship in the Channel. The path disappeared after a
few days so I feel it may have been an anchored ship.
Sent from my
Samsung Galaxy smartphone.
-------- Original message --------
Date: 22/09/2020 08:42 (GMT+00:00)
Subject: Re: [UKMicrowaves] Tropo
Whilst at least one well-known propagation pundit reckons
it is due to vertical incidence refraction out over the
North Sea, I think it is far more likely reflections from
structures on the opposite coastline. There is certainly a
strong body of evidence for vertical incidence, such as
outflow from the Rhine etc, radar reflections are also a
well known and used propagation mode.
Until we have beacons with suitable
modulation modes/time to measure time of flight, I guess
we will continue to guess at the propagation mode.
Wider bandwidths, using SDR
receivers, should make this feasible.
------ Original Message ------
From: "John Lemay"
<john@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 08:14
Subject: Re: [UKMicrowaves] Tropo
That
tropo was good fun – as well as being a bit
frustrating at times !
In
addition to the Scandinavian tropo already noted, I
was very pleased to work up to IO86, IO87 and IO97
from JO01.
One
thing I need help in understanding; On Sunday
evening, there were some very skew paths across the
North Sea, For example, the strongest signal from
SM6VTZ on 23cms was when I beamed at about 80
degrees. The direct path is at 40 degrees. When we
QSY’d to 3cms, only the direct path was viable. How
does that work ?
John
G4ZTR
Super tropo as seen here near the East coast. Lots of
beacons and some nice DX contacts. The SK1SHH (JO97CJ)
beacon was heard on 10GHz during the morning up to
529, distance 1234km, and signals exchanged with
SM1HOW (JO97GL) but QSB prevented a QSO. Signals to
the Stockholm area increased during the evening, an
initial test at 17:40 with SK0EN (JO99JX) resulted in
a good 23cm QSO but nil on 6cm. We tried again around
20:00z and exchanged 579 on 5760MHz, and then QSYd to
3cm, where signals were 529 each way after aligning
antennas, and came up to S5 by the end when we
exchanged a few words on SSB. Distance from here to
SK0EN is 1395km, my best DX on these two bands to
date. I also worked SM7GEP (JO77IP) on 3cm at 1058km.
73
John G3XDY
On
21/09/2020 22:05, Neil Smith G4DBN wrote:
For the first time in weeks, I can't hear even a
faint sniff from GB3OSW, and KBQ is absent as well.
I can decode GB3PKT on averaging at -19dB, but other
than CAM and obviously FNY, things are very flat.
Last night I was hearing OZ5SHF and DB0GHZ very
well, but nothing much inland in PA. PA0O/b was a
nice signal for 200mW in JO33, and F5ZTR was romping
in for several hours along with F1BQ through some of
my trees. No actual humans about at that time of
night. DB0GHZ is still there at S2 or so now. It is
behind a 600ft hill, so not exactly an optimal path
from here.
Neil G4DBN
On
21/09/2020 22:38, John Fell wrote:
Hi
Dave ,
I
was very impressed to see your recent Beacon
Spots and did actually visualise Hay Tor !
Been
a long time since we (G4RFR/P) activated
Oakment Hill on the North side , but Iguess
that would have had some strong signals to the
East .
Typically
it all seems very flat so far this evening and
RS is the probable mechanism for the next few
days .
Hello
John,
Thanks
for your comments. I was pretty
pessimistic at working anything today as I
was outside the main ducting area. Anyway
I went out for 10 pm last night and
immmediatly started hearing interesting
beacons. I went to the higher car park at
400m asl at Haytor as I was aware how
difficult the path is for me to get to the
east coast. The problem seems to be the
Black Down Hills. There I was hearing
GB3PKT, GB3SEE and GB3LEX all night. I
heard lots of PI beacons ,ON ,two F
several DB and three of the OZ beacons
throughout the night,which fluctuated in
strength . I did manage a QSO with OZ1 FF
at 0645Z but I wasn’t able to contact
people to work in the middle of the night
,predictably. Like you I could see a high
level inversion later, which persisted
until beyond mid afternoon. What an
amazing night and morning. Exciting stuff
for 10ghz.
David
G4GLT.
Some
excellent long haul beacons on 10GHz
again this morning , with band still
well open across to EU from here in
IO80 till 09.30 UTC .
I
was walking along the prom at
Bournemouth looking at the 6 large
cruise ships anchored in the bay ,
including the Arora , the largest
in the World , when I noticed a
distinct brown smear across almost
a full 90 degree arc .This slowly
lifted and went at 12.30 ish .
It
makes me consider if the prospects
for more Tropo this late
Sept/October are good , with the
large reduction in high level man
made clag .
Probably
just the fading memories of an old
G8 + 3 callsign , when 144/432MHz
DX was a regular Autumnal
event....
--
Neil
http://g4dbn.uk
|
|
|
Over the North Irish Sea we occasionally observe a similar effect on 23cms. Very strong signals from coastal stations in GI, GM, G and GW arrive over wide arcs, often peaking on a non-direct beam heading.
It happened at the start of the 23cms UKAC this month. GD1MIP was 30dB stronger than normal when we were both beaming towards G. The signal was also about 30dB stronger then observed or calculated from the reflection off a man made object.
I suspect it is some form of internal reflection off the edge of a partial dome of moist air surrounded by warmer drier air. Effectively a whispering gallery with signals trapped in 3 dimensions not 2. Interestingly at the time I was working GD1MIP I appeared to be cut off from all stations well inland, rather like being in a silvered bubble. This model requires a sudden change in RF refractive index in the vertical plain, which appears plausible with dry warm air pushing out over the sea. This also fits with the weather pattern of the last few days with dry easterly winds pushing unevenly out across the North Sea.
For an analogy imagine sea fog banks reflected light, you would see displaced images of distant objects.
73s
Richard
GD8EXI
toggle quoted messageShow quoted text
On 22/09/2020, 10:22, "John Lemay" < john@...> wrote:
“Ship-scatter” …. got to be careful how you say that !.
That could work. Beaming east from here Harwich/Felixstowe is about 30km and a fully laden container ship is a sizeable reflecting lump. But these skew paths only happen from time to time, coincident with tropo (as far as I can tell).
John G4ZTR
From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Paul Randall G3NJV
Sent: 22 September 2020 09:00
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo
Similarly heard MCB on 23cm from 100 degrees as well as direct NE. Surprised because 100 degrees from my qth on the Lizard is straight out across the sea, a lot further before you meet anything compared to the direct path. I surmised either a reflection from something in South Devon or a ship in the Channel. The path disappeared after a few days so I feel it may have been an anchored ship.
Paul
Sent from my Samsung Galaxy smartphone.
-------- Original message --------
From: "SAM JEWELL via groups.io" <jewell@...>
Date: 22/09/2020 08:42 (GMT+00:00)
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo
Whilst at least one well-known propagation pundit reckons it is due to vertical incidence refraction out over the North Sea, I think it is far more likely reflections from structures on the opposite coastline. There is certainly a strong body of evidence for vertical incidence, such as outflow from the Rhine etc, radar reflections are also a well known and used propagation mode.
Until we have beacons with suitable modulation modes/time to measure time of flight, I guess we will continue to guess at the propagation mode.
Wider bandwidths, using SDR receivers, should make this feasible.
73 de Sam, G4DDK
------ Original Message ------
From: "John Lemay" <john@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 08:14
Subject: Re: [UKMicrowaves] Tropo
That tropo was good fun – as well as being a bit frustrating at times !
In addition to the Scandinavian tropo already noted, I was very pleased to work up to IO86, IO87 and IO97 from JO01.
One thing I need help in understanding; On Sunday evening, there were some very skew paths across the North Sea, For example, the strongest signal from SM6VTZ on 23cms was when I beamed at about 80 degrees. The direct path is at 40 degrees. When we QSY’d to 3cms, only the direct path was viable. How does that work ?
John G4ZTR
Fromded: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of John Quarmby via groups.io
Sent: 22 September 2020 00:37
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo
Super tropo as seen here near the East coast. Lots of beacons and some nice DX contacts. The SK1SHH (JO97CJ) beacon was heard on 10GHz during the morning up to 529, distance 1234km, and signals exchanged with SM1HOW (JO97GL) but QSB prevented a QSO. Signals to the Stockholm area increased during the evening, an initial test at 17:40 with SK0EN (JO99JX) resulted in a good 23cm QSO but nil on 6cm. We tried again around 20:00z and exchanged 579 on 5760MHz, and then QSYd to 3cm, where signals were 529 each way after aligning antennas, and came up to S5 by the end when we exchanged a few words on SSB. Distance from here to SK0EN is 1395km, my best DX on these two bands to date. I also worked SM7GEP (JO77IP) on 3cm at 1058km.
73
John G3XDY
On 21/09/2020 22:05, Neil Smith G4DBN wrote:
For the first time in weeks, I can't hear even a faint sniff from GB3OSW, and KBQ is absent as well. I can decode GB3PKT on averaging at -19dB, but other than CAM and obviously FNY, things are very flat. Last night I was hearing OZ5SHF and DB0GHZ very well, but nothing much inland in PA. PA0O/b was a nice signal for 200mW in JO33, and F5ZTR was romping in for several hours along with F1BQ through some of my trees. No actual humans about at that time of night. DB0GHZ is still there at S2 or so now. It is behind a 600ft hill, so not exactly an optimal path from here.
Neil G4DBN
On 21/09/2020 22:38, John Fell wrote:
Hi Dave ,
I was very impressed to see your recent Beacon Spots and did actually visualise Hay Tor !
Been a long time since we (G4RFR/P) activated Oakment Hill on the North side , but Iguess that would have had some strong signals to the East .
Typically it all seems very flat so far this evening and RS is the probable mechanism for the next few days .
73
John
G0API
On Mon, 21 Sep 2020 at 21:41, Dave via groups.io <http://groups.io> <davidnewman55@... <mailto:icloud.com@groups.io> > wrote:
Hello John,
Thanks for your comments. I was pretty pessimistic at working anything today as I was outside the main ducting area. Anyway I went out for 10 pm last night and immmediatly started hearing interesting beacons. I went to the higher car park at 400m asl at Haytor as I was aware how difficult the path is for me to get to the east coast. The problem seems to be the Black Down Hills. There I was hearing GB3PKT, GB3SEE and GB3LEX all night. I heard lots of PI beacons ,ON ,two F several DB and three of the OZ beacons throughout the night,which fluctuated in strength . I did manage a QSO with OZ1 FF at 0645Z but I wasn’t able to contact people to work in the middle of the night ,predictably. Like you I could see a high level inversion later, which persisted until beyond mid afternoon. What an amazing night and morning. Exciting stuff for 10ghz.
Best wishes,
David G4GLT.
On 21 Sep 2020, at 20:54, John Fell <john.g0api@... <mailto:john.g0api@...> > wrote:
Some excellent long haul beacons on 10GHz again this morning , with band still well open across to EU from here in IO80 till 09.30 UTC .
I was walking along the prom at Bournemouth looking at the 6 large cruise ships anchored in the bay , including the Arora , the largest in the World , when I noticed a distinct brown smear across almost a full 90 degree arc .This slowly lifted and went at 12.30 ish .
It makes me consider if the prospects for more Tropo this late Sept/October are good , with the large reduction in high level man made clag .
Probably just the fading memories of an old G8 + 3 callsign , when 144/432MHz DX was a regular Autumnal event....
73
John
G0API/G8MCP
|
|
|
Andy G4JNT
You can get good time resolution in a chirp just 3kHz wide - so nothing special is needed licence-wise. Many years ago, G3PLX made a whole range of measurements at HF using the many GPS timed chirpsounders around the world. These chirp at 100kHz/s, sweeping the whole spectrum, but he listened in only specific 3kHz slots, waiting for the blip to pass through. The resulting blip is 30ms long. I took part in these tests, and his monitoring software was impressive, being able to measure the chirps to precision of a couple of hundred microseconds, or perhaps 60km. That limitation was as much about the soundcard sampling rate limitation than anything else. He provided a calibration procedure to take out SSB receiver delays that made use of teh PPS signal generating a wideband pulse that was fed into the input of the receiver to measure its delay.
It was all written up in RadCom but I've forgotten when and it would take some searching, so copying this email to Peter - perhaps you could let me know when it was.
I wrote PIC code that could generate a GPS timed 30ms, 100kHz/s blip at audio for a PIC, using an R-2R ladder back in the days of early PICs without PWM generators, fed it into an upconverter and sure enough, the chirpsounder software would identify it and tell me what delay I'd programmed into the PIC.
You presumably want a bit better better than that several tens of km resolution, so how about a few repeated chirps in a 3kHz or 5kHz bandwidth. Easily done with a DDS source, GPS timing and a PIC (other processors are available)
On Tue, 22 Sep 2020 at 10:52, Neil Smith G4DBN < neil@...> wrote:
I often get skew and duplicate paths from DB0GHZ, with two peaks
around 5-10 degrees apart, and sometimes there is no direct signal
and the skew can be 30 degrees or more. There isn't anything much
to reflect off other than perhaps Denmark, but then I'd expect to
see OZ beacons as well.
Perhaps we should be looking to fund chirped beacons with very
tight GPS time-sync for time-of-flight analysis? On a straight
path with around 2 milliseconds of delay, what sort of chirp or
sequence timing would be needed to get enough resolution? Would
the necessary bandwidth be licenceable? If not, perhaps an
alternative would be a network of strategically-placed
reverse-beacon receivers with GPS sync, used to receive attended
transmissions from home stations in a similar approach to the
ADS-B receive network?
Neil
On 22/09/2020 10:22, John Lemay wrote:
“Ship-scatter”
…. got to be careful how you say that !.
That
could work. Beaming east from here Harwich/Felixstowe is
about 30km and a fully laden container ship is a sizeable
reflecting lump. But these skew paths only happen from time
to time, coincident with tropo (as far as I can tell).
John
G4ZTR
Similarly heard MCB on 23cm from 100
degrees as well as direct NE. Surprised because 100 degrees
from my qth on the Lizard is straight out across the sea, a
lot further before you meet anything compared to the direct
path. I surmised either a reflection from something in South
Devon or a ship in the Channel. The path disappeared after a
few days so I feel it may have been an anchored ship.
Sent from my
Samsung Galaxy smartphone.
-------- Original message --------
Date: 22/09/2020 08:42 (GMT+00:00)
Subject: Re: [UKMicrowaves] Tropo
Whilst at least one well-known propagation pundit reckons
it is due to vertical incidence refraction out over the
North Sea, I think it is far more likely reflections from
structures on the opposite coastline. There is certainly a
strong body of evidence for vertical incidence, such as
outflow from the Rhine etc, radar reflections are also a
well known and used propagation mode.
Until we have beacons with suitable
modulation modes/time to measure time of flight, I guess
we will continue to guess at the propagation mode.
Wider bandwidths, using SDR
receivers, should make this feasible.
------ Original Message ------
From: "John Lemay"
<john@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 08:14
Subject: Re: [UKMicrowaves] Tropo
That
tropo was good fun – as well as being a bit
frustrating at times !
In
addition to the Scandinavian tropo already noted, I
was very pleased to work up to IO86, IO87 and IO97
from JO01.
One
thing I need help in understanding; On Sunday
evening, there were some very skew paths across the
North Sea, For example, the strongest signal from
SM6VTZ on 23cms was when I beamed at about 80
degrees. The direct path is at 40 degrees. When we
QSY’d to 3cms, only the direct path was viable. How
does that work ?
John
G4ZTR
Super tropo as seen here near the East coast. Lots of
beacons and some nice DX contacts. The SK1SHH (JO97CJ)
beacon was heard on 10GHz during the morning up to
529, distance 1234km, and signals exchanged with
SM1HOW (JO97GL) but QSB prevented a QSO. Signals to
the Stockholm area increased during the evening, an
initial test at 17:40 with SK0EN (JO99JX) resulted in
a good 23cm QSO but nil on 6cm. We tried again around
20:00z and exchanged 579 on 5760MHz, and then QSYd to
3cm, where signals were 529 each way after aligning
antennas, and came up to S5 by the end when we
exchanged a few words on SSB. Distance from here to
SK0EN is 1395km, my best DX on these two bands to
date. I also worked SM7GEP (JO77IP) on 3cm at 1058km.
73
John G3XDY
On
21/09/2020 22:05, Neil Smith G4DBN wrote:
For the first time in weeks, I can't hear even a
faint sniff from GB3OSW, and KBQ is absent as well.
I can decode GB3PKT on averaging at -19dB, but other
than CAM and obviously FNY, things are very flat.
Last night I was hearing OZ5SHF and DB0GHZ very
well, but nothing much inland in PA. PA0O/b was a
nice signal for 200mW in JO33, and F5ZTR was romping
in for several hours along with F1BQ through some of
my trees. No actual humans about at that time of
night. DB0GHZ is still there at S2 or so now. It is
behind a 600ft hill, so not exactly an optimal path
from here.
Neil G4DBN
On
21/09/2020 22:38, John Fell wrote:
Hi
Dave ,
I
was very impressed to see your recent Beacon
Spots and did actually visualise Hay Tor !
Been
a long time since we (G4RFR/P) activated
Oakment Hill on the North side , but Iguess
that would have had some strong signals to the
East .
Typically
it all seems very flat so far this evening and
RS is the probable mechanism for the next few
days .
Hello
John,
Thanks
for your comments. I was pretty
pessimistic at working anything today as I
was outside the main ducting area. Anyway
I went out for 10 pm last night and
immmediatly started hearing interesting
beacons. I went to the higher car park at
400m asl at Haytor as I was aware how
difficult the path is for me to get to the
east coast. The problem seems to be the
Black Down Hills. There I was hearing
GB3PKT, GB3SEE and GB3LEX all night. I
heard lots of PI beacons ,ON ,two F
several DB and three of the OZ beacons
throughout the night,which fluctuated in
strength . I did manage a QSO with OZ1 FF
at 0645Z but I wasn’t able to contact
people to work in the middle of the night
,predictably. Like you I could see a high
level inversion later, which persisted
until beyond mid afternoon. What an
amazing night and morning. Exciting stuff
for 10ghz.
David
G4GLT.
Some
excellent long haul beacons on 10GHz
again this morning , with band still
well open across to EU from here in
IO80 till 09.30 UTC .
I
was walking along the prom at
Bournemouth looking at the 6 large
cruise ships anchored in the bay ,
including the Arora , the largest
in the World , when I noticed a
distinct brown smear across almost
a full 90 degree arc .This slowly
lifted and went at 12.30 ish .
It
makes me consider if the prospects
for more Tropo this late
Sept/October are good , with the
large reduction in high level man
made clag .
Probably
just the fading memories of an old
G8 + 3 callsign , when 144/432MHz
DX was a regular Autumnal
event....
--
Neil
http://g4dbn.uk
|
|
|
Do you get elevation variations as well on the different headings? Dave ZL3FJ
From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, September 22, 2020 21:52
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo I often get skew and duplicate paths from DB0GHZ, with two peaks around 5-10 degrees apart, and sometimes there is no direct signal and the skew can be 30 degrees or more. There isn't anything much to reflect off other than perhaps Denmark, but then I'd expect to see OZ beacons as well. Perhaps we should be looking to fund chirped beacons with very tight GPS time-sync for time-of-flight analysis? On a straight path with around 2 milliseconds of delay, what sort of chirp or sequence timing would be needed to get enough resolution? Would the necessary bandwidth be licenceable? If not, perhaps an alternative would be a network of strategically-placed reverse-beacon receivers with GPS sync, used to receive attended transmissions from home stations in a similar approach to the ADS-B receive network? Neil On 22/09/2020 10:22, John Lemay wrote: “Ship-scatter” …. got to be careful how you say that !. That could work. Beaming east from here Harwich/Felixstowe is about 30km and a fully laden container ship is a sizeable reflecting lump. But these skew paths only happen from time to time, coincident with tropo (as far as I can tell). John G4ZTR Similarly heard MCB on 23cm from 100 degrees as well as direct NE. Surprised because 100 degrees from my qth on the Lizard is straight out across the sea, a lot further before you meet anything compared to the direct path. I surmised either a reflection from something in South Devon or a ship in the Channel. The path disappeared after a few days so I feel it may have been an anchored ship. Sent from my Samsung Galaxy smartphone. -------- Original message -------- Date: 22/09/2020 08:42 (GMT+00:00) Subject: Re: [UKMicrowaves] Tropo
Whilst at least one well-known propagation pundit reckons it is due to vertical incidence refraction out over the North Sea, I think it is far more likely reflections from structures on the opposite coastline. There is certainly a strong body of evidence for vertical incidence, such as outflow from the Rhine etc, radar reflections are also a well known and used propagation mode.
Until we have beacons with suitable modulation modes/time to measure time of flight, I guess we will continue to guess at the propagation mode. Wider bandwidths, using SDR receivers, should make this feasible.
------ Original Message ------
From: "John Lemay" <john@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 08:14
Subject: Re: [UKMicrowaves] Tropo
That tropo was good fun – as well as being a bit frustrating at times ! In addition to the Scandinavian tropo already noted, I was very pleased to work up to IO86, IO87 and IO97 from JO01. One thing I need help in understanding; On Sunday evening, there were some very skew paths across the North Sea, For example, the strongest signal from SM6VTZ on 23cms was when I beamed at about 80 degrees. The direct path is at 40 degrees. When we QSY’d to 3cms, only the direct path was viable. How does that work ? John G4ZTR Super tropo as seen here near the East coast. Lots of beacons and some nice DX contacts. The SK1SHH (JO97CJ) beacon was heard on 10GHz during the morning up to 529, distance 1234km, and signals exchanged with SM1HOW (JO97GL) but QSB prevented a QSO. Signals to the Stockholm area increased during the evening, an initial test at 17:40 with SK0EN (JO99JX) resulted in a good 23cm QSO but nil on 6cm. We tried again around 20:00z and exchanged 579 on 5760MHz, and then QSYd to 3cm, where signals were 529 each way after aligning antennas, and came up to S5 by the end when we exchanged a few words on SSB. Distance from here to SK0EN is 1395km, my best DX on these two bands to date. I also worked SM7GEP (JO77IP) on 3cm at 1058km. 73 John G3XDY On 21/09/2020 22:05, Neil Smith G4DBN wrote: For the first time in weeks, I can't hear even a faint sniff from GB3OSW, and KBQ is absent as well. I can decode GB3PKT on averaging at -19dB, but other than CAM and obviously FNY, things are very flat. Last night I was hearing OZ5SHF and DB0GHZ very well, but nothing much inland in PA. PA0O/b was a nice signal for 200mW in JO33, and F5ZTR was romping in for several hours along with F1BQ through some of my trees. No actual humans about at that time of night. DB0GHZ is still there at S2 or so now. It is behind a 600ft hill, so not exactly an optimal path from here. Neil G4DBN On 21/09/2020 22:38, John Fell wrote: Hi Dave , I was very impressed to see your recent Beacon Spots and did actually visualise Hay Tor ! Been a long time since we (G4RFR/P) activated Oakment Hill on the North side , but Iguess that would have had some strong signals to the East . Typically it all seems very flat so far this evening and RS is the probable mechanism for the next few days . Hello John, Thanks for your comments. I was pretty pessimistic at working anything today as I was outside the main ducting area. Anyway I went out for 10 pm last night and immmediatly started hearing interesting beacons. I went to the higher car park at 400m asl at Haytor as I was aware how difficult the path is for me to get to the east coast. The problem seems to be the Black Down Hills. There I was hearing GB3PKT, GB3SEE and GB3LEX all night. I heard lots of PI beacons ,ON ,two F several DB and three of the OZ beacons throughout the night,which fluctuated in strength . I did manage a QSO with OZ1 FF at 0645Z but I wasn’t able to contact people to work in the middle of the night ,predictably. Like you I could see a high level inversion later, which persisted until beyond mid afternoon. What an amazing night and morning. Exciting stuff for 10ghz. David G4GLT. Some excellent long haul beacons on 10GHz again this morning , with band still well open across to EU from here in IO80 till 09.30 UTC . I was walking along the prom at Bournemouth looking at the 6 large cruise ships anchored in the bay , including the Arora , the largest in the World , when I noticed a distinct brown smear across almost a full 90 degree arc .This slowly lifted and went at 12.30 ish . It makes me consider if the prospects for more Tropo this late Sept/October are good , with the large reduction in high level man made clag . Probably just the fading memories of an old G8 + 3 callsign , when 144/432MHz DX was a regular Autumnal event....
-- Neil http://g4dbn.uk
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I find the sometimes I have to elevate up to 1.5 degrees to get
the best signal level from DB0GHZ and OZ, but the whole thing is
complicated by there being a 170 m ridge between me and the coast,
57 km away, so getting into any duct low over the sea is a
challenge. Perhaps elevated duct entries might be easier because
of that ridge?
Path profile in the direction of DB0GHZ looks like this for the
first 63 km. The rest of the path is over the sea, another 520km
away. I am at almost 5m asl. The "horizon" in that direction is
already at +0.4 degrees because of the ridge line. Image from the
excellent path profile software from Mike Willis.
I must say that fitting elevation to my terrestrial microwave
antennas has been a revelation
Neil G4DBN
toggle quoted messageShow quoted text
On 22/09/2020 11:39, Dave Brown wrote:
Do
you get elevation variations as well on the different
headings?
Dave
ZL3FJ
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Remember that there is frequently a boundary step in temperature and humidity at around the 600hPa level (700 – 1000m asl). This is enough the give
a local angle of arrival change of about 1.2 degrees
I have found it extremely useful to exploit for short obstructed paths.
The recent tropo event has also seen elevation differences between “local” and dx (800km+) of a measured 0.4 degrees
Nick – g4ogi
toggle quoted messageShow quoted text
From: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
On Behalf Of Neil Smith G4DBN via groups.io
Sent: 22 September 2020 12:14
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo
I find the sometimes I have to elevate up to 1.5 degrees to get the best signal level from DB0GHZ and OZ, but the whole thing is complicated by there being a 170 m ridge between me and the coast, 57 km away, so getting into any duct low over the sea is a
challenge. Perhaps elevated duct entries might be easier because of that ridge?
Path profile in the direction of DB0GHZ looks like this for the first 63 km. The rest of the path is over the sea, another 520km away. I am at almost 5m asl. The "horizon" in that direction is already at +0.4 degrees because of the ridge line. Image from
the excellent path profile software from Mike Willis.
I must say that fitting elevation to my terrestrial microwave antennas has been a revelation
Neil G4DBN
On 22/09/2020 11:39, Dave Brown wrote:
Do you get elevation variations as well on the different headings?
Dave ZL3FJ
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Not sure my rotator was ever that accurate and I certainly couldn't vary my elevation but have seen the skewed path syndrome several times over the decades on 23cm.
Unfortunately no aerial on mast at the moment for 23cms so can't comment on the last few days but being so far inland I can't imagine for a moment that I would have been able to reflect off of a ship or something on the Dutch coast! When I have seen the effect it was always with GM stations. Not sure of exact bearings but I would be beaming toward SM as would the GM station and signals would be stronger than on a direct path.
I've stayed on 2m and 70cms over the last few days and I did not see any signs of a skewed path, all signals appeared to peak direct though they were easily audible over a much wider bearing than would be normal due to the strengths involved at times.
Regards
Tony G4NBS
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I don't think there will be any tropospheric propagation via 'vertical incidence'. However, we are interested in the vertical refractive index profile because that provides an indication of whether or not ducting is likely. Is there a mix-up in terminology in an earlier posting?
Looking at radiosonde data for Schleswig (Northern Germany for Sunday 20 September at 1200 UTC and Monday 21 September at 0000 UTC, there is evidence of a very strong elevated duct - sufficiently strong to support VHF and UHF. Was there tropo activity on 2 m and 70 cm this weekend? I don't know because I'm HF QRP and currently without an antenna.
The elevated duct and inland stations might be an indication that the off-great-circle paths are not caused by reflections from ships. Hills/mountains?
With HF propagation, there can be horizontal gradients in the electron density in the ionosphere, which results in bearings that are not great-circle. Could a similar effect be happening within the troposphere? In other words, there is refraction in the horizontal plane (or at least not vertical), as well as in the vertical plane.
Perhaps anomalous bearings could be collected from multiple stations to see if there is a common characteristic or focal point on a map? What about weather conditions in this region, if one is identified?
73 Marcus G0IJZ
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Although we are probably agreed it was predominantly an elevated duct for the real DX, the number and strength of Dutch stations on 2 and 70 (maybe a few on 23cm but activity is lower) seems to indicate a low level surface duct was also present. Reflections from single ships and builds are not likely to result in much of a reflection, but we are talking about hundreds, if not thousands of significant buildings/ structures along the coast and within the common volume beamwidth of the antennas. On 2m there was some evidence of multipath on some of the stronger FT8 signals in the UK, who were, presumably, beaming east towards the continent. I have, over the years, worked a number of northern England and Scotland stations by beaming eastish from here in Suffolk. This mainly on 23cm, back when there was more activity. Skew paths on 10GHz are quite common and again it may be reflection or refraction. The Galloper and Great Gabbard wind farms are the biggest contributors here. I might add that the Belgian radar on 23cm was really strong the last few days. The noise blanker really was unable to take it out on any setting. Not just every eight seconds of rotation, but continuous, as it rotated and reflected from every object it illuminated!
73 de Sam, G4DDK
toggle quoted messageShow quoted text
------ Original Message ------
From: "Marcus Walden" <marcus.g0ijz@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 14:57
Subject: Re: [UKMicrowaves] Tropo
I don't think there will be any tropospheric propagation via 'vertical incidence'. However, we are interested in the vertical refractive index profile because that provides an indication of whether or not ducting is likely. Is there a mix-up in terminology in an earlier posting?
Looking at radiosonde data for Schleswig (Northern Germany for Sunday 20 September at 1200 UTC and Monday 21 September at 0000 UTC, there is evidence of a very strong elevated duct - sufficiently strong to support VHF and UHF. Was there tropo activity on 2 m and 70 cm this weekend? I don't know because I'm HF QRP and currently without an antenna.
The elevated duct and inland stations might be an indication that the off-great-circle paths are not caused by reflections from ships. Hills/mountains?
With HF propagation, there can be horizontal gradients in the electron density in the ionosphere, which results in bearings that are not great-circle. Could a similar effect be happening within the troposphere? In other words, there is refraction in the horizontal plane (or at least not vertical), as well as in the vertical plane.
Perhaps anomalous bearings could be collected from multiple stations to see if there is a common characteristic or focal point on a map? What about weather conditions in this region, if one is identified?
73 Marcus G0IJZ
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I might add that the Belgian radar on 23cm was really strong the last few days. The noise blanker really was unable to take it out on any setting. Not just every eight seconds of rotation, but continuous, as it rotated and reflected from every object it illuminated!
73 de Sam, G4DDK
Ah, that's what it was then. I was getting this constant blip every few seconds. Pleased, didn't realize I could get that far!! hi
Ben
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There are multiple contributing factors that have made for some interesting propagation conditions this autumn.
The main highlights from an amateur radio perspective is that a relatively stable High pressure region formed consistently of multiple High pressure systems. Their dissipation allowing elevated temperature
inversions to occur and also existed opportunity underneath for an almost contiguous surface duct to form.
If you look at the appropriate data (Skew-T Charts) across a number of cities across Europe you will quickly see that these temperature inversions were at 950 (~500m asl) and 750hPa (~2500m asl).
The low level inversion has been present from Manchester to Warsaw and from Stockholm to Stuttgart and provided microwavers with decent opportunities for contacts. The higher level one has been a little patchier and from the data I have collected seems more
confined more to northern areas of Europe (Copenhagen and northern Germany) and thus probably confused many VHFers
I have said on this reflector before that skewed propagation are the result of refraction through an air mass body. This mass will be subject to changes in temperature, humidity, local pressure and
wind which will contribute to a swirling (slow moving) mixing blob with variable refraction properties. The speed of mixing takes place over hours and can produce strong localised refraction in any plane (it is a 3D body). At microwave frequencies it is not
unusual to see angles of arrival varying a number of degrees in azimuth over a short time.
Local signals here tended to remain anchored to the horizon (0 deg) elevation) but significant (3dB or so) improvement to some long haul signals were measured (SK1SHH at 1306km, OZ1UHF at 915km)
with the dish elevated by between 0.2 – 0.4 degrees.
Nick – g4ogi
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From: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
On Behalf Of SAM JEWELL via groups.io
Sent: 22 September 2020 16:10
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Tropo
Although we are probably agreed it was predominantly an elevated duct for the real DX, the number and strength of Dutch stations on 2 and 70 (maybe a few on 23cm but activity is lower) seems to indicate a low level surface duct was also
present.
Reflections from single ships and builds are not likely to result in much of a reflection, but we are talking about hundreds, if not thousands of significant buildings/ structures along the coast and within the common volume beamwidth of
the antennas.
On 2m there was some evidence of multipath on some of the stronger FT8 signals in the UK, who were, presumably, beaming east towards the continent.
I have, over the years, worked a number of northern England and Scotland stations by beaming eastish from here in Suffolk. This mainly on 23cm, back when there was more activity. Skew paths on 10GHz are quite common and again it may be
reflection or refraction. The Galloper and Great Gabbard wind farms are the biggest contributors here.
I might add that the Belgian radar on 23cm was really strong the last few days. The noise blanker really was unable to take it out on any setting. Not just every eight seconds of rotation, but continuous, as it rotated and reflected from
every object it illuminated!
------ Original Message ------
From: "Marcus Walden" <marcus.g0ijz@...>
To: UKMicrowaves@groups.io
Sent: Tuesday, 22 Sep, 20 At 14:57
Subject: Re: [UKMicrowaves] Tropo
I don't think there will be any tropospheric propagation via 'vertical incidence'. However, we are interested in the vertical refractive index profile because that provides an indication of whether or not ducting is likely. Is there a mix-up
in terminology in an earlier posting?
Looking at radiosonde data for Schleswig (Northern Germany for Sunday 20 September at 1200 UTC and Monday 21 September at 0000 UTC, there is evidence of a very strong elevated duct - sufficiently strong to support VHF and UHF. Was there tropo activity on 2
m and 70 cm this weekend? I don't know because I'm HF QRP and currently without an antenna.
The elevated duct and inland stations might be an indication that the off-great-circle paths are not caused by reflections from ships. Hills/mountains?
With HF propagation, there can be horizontal gradients in the electron density in the ionosphere, which results in bearings that are not great-circle. Could a similar effect be happening within the troposphere? In other words, there is refraction in the horizontal
plane (or at least not vertical), as well as in the vertical plane.
Perhaps anomalous bearings could be collected from multiple stations to see if there is a common characteristic or focal point on a map? What about weather conditions in this region, if one is identified?
73 Marcus G0IJZ
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