The recent propagation conditions: a few notes

We see these unusual conditions from time to time, but this was the first
time that I've had the opportunity to study the results of one event at
several radically different locations.



On Tuesday at 2.30pm I parked the motorhome on the road from Braithwell to
Ravenfield, at a point where the road is about 450 ft above sea level and
there are clear views all round. Belmont is line-of-sight, but reception was
very poor. Analogue co-channel interference was severe, as was the grainy
effect of DTT to analogue co-channel interference. With the aerial pointing
south the analogue pictures almost disappeared under the DTT, which I guess
was from Crystal Palace. Emley Moor is also line-of-sight, and the direction
is north- west, but reception was good only with the aerial exactly on-beam.
If the aerial was pointed south east the Emley pictures disappeared and were
replaced with Dutch ones. Bilsdale reception was obliterated by continental
signals. Various continental signals were visible on about ten other
channels. VHF-FM reception included most of the usual UK stations, plus
about five Dutch ones. BBC Cleveland, which is usually received loud and
clear, was replaced by a strange droning noise.



At 3.25pm I parked at the highest point on the road from Sheffield to
Castleton, about 1,600 feet above sea level. The view to the south-east
would have been spectacular from this location had it not been a bit misty.
UHF TV reception from Holland was much the same as at Braithwell. The
elevated site clearly made no difference, except that there were many more
UK signals. On FM however, there was less Dutch reception than at
Braithwell. Virtually every channel was full of noise, with large numbers of
stations competing and few of them being audible.



At 4.10pm I parked in the Hope Valley, between Hope and Castleton. The
location is surrounded by low hills, with the horizon about 7 deg above the
horizontal (I'm guessing; don't none of you mathematical types spend an
evening on this and then tell me I'm wrong). On UHF TV there was no Dutch TV
reception. The nearby UK local relays were there, and nothing else. But on
VHF FM we might as well have been in Holland. Almost all the UK signals were
absent, and a number of Dutch signals came in loud, clear, and consistent.
These included:

95.7 Radio 1

90.4 Klara

104.1 dunno, but it wiped out R Sheffield

103.0

98.6 Radio 2

102.1 Stu Bru

91.7

89.5 Klara

94.8

92.2

91.8

91.7 Radio 1

Reception from these stations was absolutely consistent, and lasted until
midnight when I turned off. On some Dutch stations the RDS kept swapping
from one frequency to another. The signals from the UK local relay were
present but noisy and prone to interference. Holme Moss signals were
obliterated. High Peak Radio (from a relay nearby) was patchy.



On Wednesday morning there was no Dutch reception except for vague sounds on
some of the frequencies listed above. Radio Sheffield reappeared on 104.1.
Classic FM (which had been totally absent the night before) reappeared from
Holme Moss and Sutton Coldfield. Various weak signals, such as Radio Derby
and Radio Lincolnshire appeared.



Perhaps what we learn from all this is that the Dutch signals arrive from
well above the horizon.



Changing the subject, I was surprised to see that Calendar from the local
relays was the Emley Moor version, full of news of murder and mayhem in
Leeds. How inappropriate, in an area well south of Sheffield and on the
fringes of Sutton Coldfield Land.



And changing the subject again, you might have read about the discovery of
the UK's largest cave, here in the valley. Well according to the locals that
I've been drinking with all night, the location of the cave entrance has
been well known locally 'for ever'. Their derision for the media was
extreme. So much for journos.



And finally, in Buxton at dusk I saw a satellite dish with a bright red LED
on the LNB. How silly.



Bill

Thanks for that Bill, very interesting. We've been having fun on the 2m
amateur band, getting stations from France, Germany, Belgium,
Netherlands, etc from monday morning till tuesday night, and I was
talking to someone who worked a german station on 70cm too. Were you
able to determine whether DTT stood up to co-channel interference better
than analogue?

On Thu, 9 Nov 2006 17:33:19 -0000, "Bill Wright"
wrote:

...
And changing the subject again, you might have read about the discovery of
the UK's largest cave, here in the valley. Well according to the locals that
I've been drinking with all night, the location of the cave entrance has
been well known locally 'for ever'. Their derision for the media was
extreme. So much for journos.

My understanding was that the cave entrance, on the surface, may have
been there 'for ever' but the entrance to the 'big' cave, underground,
was blocked by a rock fall which had only recently been breeched.

--
Alan White
Twenty-eight miles NW of Glasgow, overlooking Lochs Long and Goil in Argyll, Scotland.
Webcam and weather:- http://windycroft.gt-britain.co.uk/weather
Some walks and treks:- http://windycroft.gt-britain.co.uk/walks

A red LNB in Buxton?.....well he probably painted it to match the brakes on
his Soobaroo...

On Thu, 9 Nov 2006 17:33:19 -0000, "Bill Wright"
wrote:


And finally, in Buxton at dusk I saw a satellite dish with a bright red LED
on the LNB. How silly.

Indeed. Red ones are so eighties. Everyone knows that the only colour
for LEDs is blue these days.

Cheers,

Colin.

On Thu, 9 Nov 2006 17:33:19 -0000, "Bill Wright"
wrote:




And finally, in Buxton at dusk I saw a satellite dish with a bright red LED
on the LNB. How silly.

No sillier than those bright blue LEDs they put on car washer nozzles.
ISTR in the heyday of CB radio that you would often see a neon or LED
at the end of those huge whip aerials they used to have on their cars.
Those LEDs were powered by the transmitter!.

We used to check radar by sticking a neon in front of the dish.

JPG




Bill

On Thu, 9 Nov 2006 21:18:39 -0000, "Gendy"
wrote:

A red LNB in Buxton?.....well he probably painted it to match the brakes on
his Soobaroo...


You've misthreaded. I didn't mention that.

--
Alan White
Twenty-eight miles NW of Glasgow, overlooking Lochs Long and Goil in Argyll, Scotland.
Webcam and weather:- http://windycroft.gt-britain.co.uk/weather
Some walks and treks:- http://windycroft.gt-britain.co.uk/walks

Bill Wright wrote:
We see these unusual conditions from time to time, but this was the first
time that I've had the opportunity to study the results of one event at
several radically different locations.



On Tuesday at 2.30pm I parked the motorhome on the road from Braithwell to
Ravenfield, at a point where the road is about 450 ft above sea level and
there are clear views all round. Belmont is line-of-sight, but reception was
very poor. Analogue co-channel interference was severe, as was the grainy
effect of DTT to analogue co-channel interference. With the aerial pointing
south the analogue pictures almost disappeared under the DTT, which I guess
was from Crystal Palace. Emley Moor is also line-of-sight, and the direction
is north- west, but reception was good only with the aerial exactly on-beam.
If the aerial was pointed south east the Emley pictures disappeared and were
replaced with Dutch ones. Bilsdale reception was obliterated by continental
signals. Various continental signals were visible on about ten other
channels. VHF-FM reception included most of the usual UK stations, plus
about five Dutch ones. BBC Cleveland, which is usually received loud and
clear, was replaced by a strange droning noise.



At 3.25pm I parked at the highest point on the road from Sheffield to
Castleton, about 1,600 feet above sea level. The view to the south-east
would have been spectacular from this location had it not been a bit misty.
UHF TV reception from Holland was much the same as at Braithwell. The
elevated site clearly made no difference, except that there were many more
UK signals. On FM however, there was less Dutch reception than at
Braithwell. Virtually every channel was full of noise, with large numbers of
stations competing and few of them being audible.



At 4.10pm I parked in the Hope Valley, between Hope and Castleton. The
location is surrounded by low hills, with the horizon about 7 deg above the
horizontal (I'm guessing; don't none of you mathematical types spend an
evening on this and then tell me I'm wrong). On UHF TV there was no Dutch TV
reception. The nearby UK local relays were there, and nothing else. But on
VHF FM we might as well have been in Holland. Almost all the UK signals were
absent, and a number of Dutch signals came in loud, clear, and consistent.
These included:

95.7 Radio 1

90.4 Klara

104.1 dunno, but it wiped out R Sheffield

103.0

98.6 Radio 2

102.1 Stu Bru

91.7

89.5 Klara

94.8

92.2

91.8

91.7 Radio 1

Reception from these stations was absolutely consistent, and lasted until
midnight when I turned off. On some Dutch stations the RDS kept swapping
from one frequency to another. The signals from the UK local relay were
present but noisy and prone to interference. Holme Moss signals were
obliterated. High Peak Radio (from a relay nearby) was patchy.



On Wednesday morning there was no Dutch reception except for vague sounds on
some of the frequencies listed above. Radio Sheffield reappeared on 104.1.
Classic FM (which had been totally absent the night before) reappeared from
Holme Moss and Sutton Coldfield. Various weak signals, such as Radio Derby
and Radio Lincolnshire appeared.



Perhaps what we learn from all this is that the Dutch signals arrive from
well above the horizon.



Changing the subject, I was surprised to see that Calendar from the local
relays was the Emley Moor version, full of news of murder and mayhem in
Leeds. How inappropriate, in an area well south of Sheffield and on the
fringes of Sutton Coldfield Land.



And changing the subject again, you might have read about the discovery of
the UK's largest cave, here in the valley. Well according to the locals that
I've been drinking with all night, the location of the cave entrance has
been well known locally 'for ever'. Their derision for the media was
extreme. So much for journos.



And finally, in Buxton at dusk I saw a satellite dish with a bright red LED
on the LNB. How silly.



Bill








Bill,

You need to get out more.

Oh, wait!

No sillier than those bright blue LEDs they put on car washer nozzles.
ISTR in the heyday of CB radio that you would often see a neon or LED
at the end of those huge whip aerials they used to have on their cars.
Those LEDs were powered by the transmitter!.

We used to check radar by sticking a neon in front of the dish.

A neon I'll buy but I'd be surprised if this affect works for LEDs.
Presumably its the same affect as works for flourescent tubes under mains
pylons - again a gaseous medium.

Paul DS

Bill Wright wrote:

Perhaps what we learn from all this is that the Dutch signals arrive from
well above the horizon.

There's discussion in other forums whether the original polarisation is
maintained through a lift ?
Did you experiment with H and V planes ? AIUI all Dutch FM stations
employ vertical polz.