Northern Star
International Broadcasters AS
COMPANY STATEMENT. FIELD STRENGTH ON 216 kHz AM.
General
It
is traditionally widely recognized that especially in AM high-power
broadcasting, the coverage is tremendous, and that it is possible to reach many
millions of listeners in densely-populated areas.
With
digital modern technology, such as via DRM or HD, the commercial signal will be of high
quality.
Summary
Northern Star International
Broadcasters AS maintains that its projected radio station on AM 216 will have
a huge daytime signal over Northern Europe(The North Atlantic, Southern
Scandinavia, the Northern part of Continental Europe, the Benelux countries and
the British Isles), but like any other AM station in Europe it will encounter
nighttime interference.
Historical sketch
The coverage of the Norwegian station(LKO,
200 kW) using the channel until early 1995 became very restricted because of
the presence of Radio Monte Carlo since 1965, even if signal processing was
implemented. Rightly, it made some impact in the UK after dark, but the signal
was largely not a commercial one. The channel had been earmarked to serve the
Norwegian national broadcaster NRK in a domestic/Northern Europe network,
together with 153, 630, 675, 702 and 1314 kHz, and the initial siting of 216
was meant to be the Oslofjord area, on the island of Bast¿y. As it turned out,
however, only LKS, 1314 kHz(with high power) on the SW coast was built in 1982,
with LKF, 153 kHz(with only medium power) following in 2001 in the Arctic. From
the 80s, the French station in question also seems to have had over double its
allowed power(1.400 mW) in the Geneva Plan at its disposal. On the other hand,
the same plan implemented that the Southern France station must REDUCE power.
ie be directional WNE only 300 kW emrp in a sector starting eastwards at 309o
degrees(360o compass)
The new transmitter on 216 should have
been present since 1978, but never took the air. But alert people in the
Norwegian frequency administration felt the situation was a shame, and
therefore immediately responded in a very positive way to the long and
continuing interest in AM frequencies by what was to become Northern Star.
Also, other Norwegian authorities saw a possibility for new broadcast use of
216 with our project, and agreed with us it was a good idea to try to move the
site to the South West. Here it was possible to utilize excellent conductivity
and salt-water propagation. Not only the UK would benefit from an excellent
signal, but the station would also reach vast areas in Northern Europe to the
South and East.
Therefore, Northern Star is first and
foremost a North European project, not only a UK one. As Scandinavia is a very interesting market, we
have also researched sites in Eastern Norway, even if such a choice would have
greatly reduced the coverage of the UK, as you may see from the coverage maps
at http://www.northernstar.no/coverage.htm
However, we do not think there are sites
available.
Going back to history, certain Defence
circles showed a most unfriendly attitude, and completely destroyed the two
excellent, and quite complete utility radio sites(priced at only $8000 each by an
estate company) we could have put into good use and from which we might well
have been on the air on a smaller scale coupled to internet streaming long ago,
since we have long had a complete studio on our hands, stemming from the local
radio roots of the project. But at
last we indeed had success in lobbying for the un-used frequency towards the
Department of Culture, The Parliament, and the Mass Media Authority. In 2000,
then, it was advertised for interested parties, and in autumn 2001 a
preliminary license for our company came into in effect, while a permanent one
is to follow once the site has been finally decided and a financial guarantee
from one or more interested investors is placed on the table. With an all-lease
model proposed by the planned transmission supplier, it is reckoned in our
current BP that the capital needed for an omnidirectional station will be $10M.
The Northern Star company and Radio Norway
International project is our pride and joy. At least 8 active years of hard
work have gone by and a considerable sum of money has been spent. We are
entirely honest, and have the best expert on field strength and propagation in
our team in the form of our Norwegian consultant, Mr. Knut N.Stokke.
Knut N.StokkeÕs view
Mr. Knut N.Stokke has recently retired after many years
with the Norwegian Telecoms Administration in Oslo.(Post&Tele http://www.npt.no ). He is very highly qualified, being one of the few AM broadcasting
experts in Norway, and was the one that actually negotiated for Norway in
Geneva 1974/75, getting us the super-power channels of 153, 216, 630 and 1314
kHz, all with the option to broadcast with 1.200 megawatts. He has been very
kind and helpful towards our project since 1994. He is a big fan of the Allouis
antenna design(invented by Steph‡ne Lacharnay, and named after another French
station broadcasting on 162 kHz with 2000 kW[1] ) and has provided us with extensive material on this
device.
Mr.Stokke emphasizes: ÒThe distance from
the proposed transmitter site in Norway to London is about 870 km and mostly
sea with good conductivity, as the distance from Monte Carlo to London is
longer, about 1000 km, and mostly land with lower conductivity, and the
difference in radiated power is less than 1dB. (comment from company: 1200 and
1400 kW respectively used, even if Monte Carlo must restrict its power
considerably to the North) We should therefore expect higher ground-wave field
strength values from Norway in London than from Monte Carlo.Ó
About the calculation methods used,
Mr.Stokke says: ÒThe calculation resultsÉare based on the methods proposed and
recommended by the ITU. For the ground-wave calculations the curves and the
method(Millington) given in the ITU Atlas of Ground Conductivities(or in R-Rec.368)
are used, and for the ionospheric calculation the Cairo curves in R-Rec 435 are
used. The sea gain curve is also given in that recommendation.Ó
About conductivity: In the Atlas the
conductivity for England is given. France has not done new conductivity
measurements, and therefore we have to use the old values. (comment from
company: This very probably gives Monte Carlo values that are too good.) For
most of the countries new measurements have shown lower conductivities than the
old measurements.Ó
Calculation tables. Non-directional antenna
and 1400 kW used for Monte Carlo. Same and 1200 kW used for NOR.
|
Point |
GW field from Norway |
GW field from Monte Carlo |
Skywave from Norway |
Skywave from Monte Carlo |
|
Brighton |
1.6 mV/m |
0.56 mV/m |
4.5 mV/m |
4.5 mV/m |
|
Cardigan Bay |
2.0 mV/m |
0.22 mV/m |
4.5 mV/m |
2.8 mV/m |
|
Larne |
2.5 mV/m |
0.11 mV/m |
5.0 mV/m |
2.5 mV/m |
|
John O'Groats |
8.9 mV/m |
0.09 mV/m |
7.1 mV/m |
1.8 mV/m |
|
London |
2.0 mV/m |
0.45 mV/m |
5.6 mV/m |
4.0 mV/m |
|
Birmingham |
2.2 mV/m |
0.30 mV/m |
5.0 mV/m |
3.6 mV/m |
|
Dublin |
1.8 mV/m |
0.22 mV/m |
3.5 mV/m |
2.5 mV/m |
|
Selkirk |
6.3 mV/m |
0.10 mV/m |
6.3 mV/m |
2.5 mV/m |
As shown in the results, the ground-wave
reception(day-time reception) from Norway should dominate over the signal from
Monte Carlo in England. It is ionospheric reception(night-time reception) that
will cause problems. However, we have to remember that all the LF and MF
stations in Europe have large ionospheric interference problems. Even if the
ITU LF/MF conference in 1975 did clear up most of the serious ground-wave
reception problems, the ionospheric reception problems are still there.Ó
Generally, his response indicates very
good results for the daytime signal for the Northern Star station over the UK,
and the ratio between the Norwegian and French signal seem very satisfactory
from our point of view.
Regarding his study for the nighttime
signal, we do find what was expected- that RMC Info, also using 216 kHz will
yield competition, but that Norway will still have the edge in most parts that
we target. This is exactly the same picture for nighttime broadcasting as most
European LW/MW broadcasters experience, as Mr.Stokke explains.
Field strength
To read Mr.StokkeÕs findings in comparison
to the Norkring AS color coverage maps at http://www.northernstar.no/coverage.htm
please consult the following table: (We
cordially invite you to access and investigate our website.)
|
Comparable values regarding projected field
strength on Northern Star project coverage maps. Each
step of 10 dB microvolt/m relates to a factor of 3,16. |
||
|
50
dBmV/m |
0,32 mV/m |
Green/Purple contour |
|
60
dBmV/m |
1 mV/m |
Blue contour |
|
66 dBmV/m |
2 mV/m |
|
|
70 dBmV/m |
3 mV/m |
Red contour |
|
72 dBmV/m |
4 mV/m |
|
|
80 dBmV/m |
10 mV/m |
|
Norkring has produced maps that give
NOR even better results than Mr.StokkeÕs calculations. Not only does RMCÕs 50 dBmV/m, 0,32
mV/m
contour stop way down in France, but NORÕs 70 dBmV/m, 3
mV/m
contour covers much of the UK. This is logical when one studies each stationÕs
signal path. Much of the signal from NOR goes over salt water, while RMC has to
cross only ground with lower conductivity.
On a map made by Mr.Stokke, http://www.northernstar.no/coverage.htm
the field strength is 60 dBmV/m, 1,0 mV/m, equal to the blue contour on the Norkring color
maps.
We think that normally both 0,5, 0,7 and 1
mV/m are more than sufficient for a commercial signal on AM. However, we notice
that the BBC is using the 2 mV/m, 66 dBmV/m
level on long waves to provide a strong
enough signal in urban areas.
On 216, we think we will be able to give investors and
advertisers better values then these in many parts of Northern Europe![2].
If you calculate with a 20:1 ratio
Some consultantsÕ experience shows that a
reliable signal requires to be about 20 times stronger than the interfering
signal to overcome the interference most of time. To explain, 20:1 equals 26dB
in electrical field strength(10:1 would equal 20dB) to 1dB(for the interferer).
But this is almost exactly the same value used for the realistic signal value
used by the Norwegian delegation at the Geneva Conference 1974/1975, this was
even better at 27dB[3]. (ÓFullÓ quality would be about 32 dB, in fact the
basic values used in 1978 for the Norwegian planning for
the 1974/1975 Geneva frequency conference were 30dB
for MW and 33dB for LW signal-to interference. With no interference, the
signal-to-noise ratio will be the same.)
Concerning the minimum usable field strength (MUF), we may have
good reception at field strengths much lower than 0.5 mV/m when the
signal-to-interference ratio is better than 20 dB.
A value better than 27dB is a realistic
target, but difficult to reach on an average basis, as especially during dawn
and dusk, and the dark hours, reception vary. It is the same picture from day
to day, and during different periods of the year. In the case of 216, the NOR
and Roumoules signal will meet each other at a given point(in our consultantÕs
table estimated to be the Channel), but this point will vary within a
fluctuating zone , sometimes giving NOR, other times Roumoules the edge. On the Norkring Utsira map, http://www.northernstar.no/coverage.htm
assumed to be quite identical to what now
seems to be the likely site, the point is estimated to be pushed down into
France.
Field strength over interfering station. People will listen to a signal with a signal to
interference value down to 10 dB if the program is interesting enough.
|
|
|
<27dB |
Good reception of both speech and music |
|
20-27 dB |
Relatively good reception, interference may be
noticeable |
|
10-20 dB |
Speech transmission may be acceptable |
|
5 dB |
Speech transmission may be possible, interference
will be tiresome |
If we now look at Mr.StokkeÕs daytime projections for
Northern Star, we find that RMC Info will have about 0,56 mV/m at point A
(Brighton) while NOR will have 1,6 mV/m. In London(point E) it is 0.45 to 2,0.
This gives NOR the edge at the British Channel with 64 to 55 dB, while in
London, of course an even more urban area, the comparison is 66 to 53 dB. In
the rest of the British Isles the figures are much better, with ie 19 db better
for NOR at Cardigan Bay(point G), 27dB in Larne(point C) and 36dB in the
Borders area(point H). Therefore the following
figures are quite modest, we refer to comments above re.the Norkring coverape
maps.
|
Daytime
field strength in dBmV/m |
Nighttime
field strength in dBmV/m |
||||
|
|
NOR |
RMC |
|
NOR |
RMC |
|
A
Brighton |
64 |
55 |
A
Brighton |
73 |
73 |
|
B
Cardigan Bay |
66 |
47 |
B
Cardigan Bay |
73 |
69 |
|
C
Larne |
68 |
41 |
C
Larne |
74 |
68 |
|
D
John O'Groats |
79 |
38 |
D
John O'Groats |
77 |
65 |
|
E
London |
66 |
53 |
E
London |
75 |
72 |
|
F
Birmingham |
67 |
49 |
F
Birmingham |
74 |
71 |
|
G
Dublin |
65 |
47 |
G
Dublin |
71 |
68 |
|
H
Selkirk |
76 |
40 |
H
Selkirk |
76 |
68 |
But then this calculation was done
for a RMC Info with 1.400 mW nondirectional antenna. As mentioned, in the
Geneva Plan the station is required to be directional and only 300 kW to the
North. More about this matter below. It should also be noted that the site
proposed when the calculation was made, was Farsund-Lista/Marka.[4] An old conductivity map had to be used for
France, giving RMC better values than what is realistic. We also think that
when we are able to broadcast Digital AM, this will get rid of any
interference.
The nighttime signals of both stations over the
British Isles are considerable, with neither of them having any edge in
Brighton, gradually improving in NORÕs favour the further north we go. The
nighttime signal of Northern Star over the UK seems certainly to be more
limited during nighttime. On the other hand our plans for 216 are not only for
the UK, we target all of Northern Europe.
Also here, the calculations were
done for a RMC Info with a 1.400 mW nondirectional, but their allocation is
much more restricted. Even more here, broadcasts in Digital AM will get rid of
any interference.
We emphasize that we see the problem of nighttime
interference. Anyone who wants to run an AM station in Europe will encounter
it, as has Atlantic 252 from Ireland, as well as Virgin and Talksport in the
UK. And these are domestic UK transmitters. But interference is a problem found
in all Europe that has its roots in the Geneva Plan. It is also due to a great
number of transmitters in a relatively small region.
-The RMC Info question
We have never hidden the challenge
represented by the French Plateau de Valensole (near the Riviera) co-channel
station. Ever since this station hit the airwaves in March 1965, it has presented
a considerable problem for Norwegian authorities: ÒMonaco
built a big station(then 1.200 mW) on the frequency of Oslo-Kl¿fta without any
prior contact.Ó[5]
We see the RMC question as a strategic challenge.
However, Norwegian authorities, such as the Mass Media Authority, Post&Tele
and Telenor ASA/Norkring AS, our site and transmission partner assure us that
they fully back the Norwegian allocation on 216, 1200 kW. RMC Info is required by the Geneva Plan to be directional
and only 300 kW to the North. From 309o westwards, it is allowed
1400 kW.
Possibilities for improvement of signal
We should briefly mention that other
factors too will improve our signal:
- Optimod-AM processing
- Higher modulation
- Broader Bandwidth
- Directional antennas
á
Digital AM. Here
you will get FM-type quality over long distances, with maybe as much as 15 kHz
bandwidth. See
http://www.drm.org
- Using an additional
site/and/or waveband in another country
The important matter
If one wants to engage in AM broadcasting
in the future in Europe it is essential to get hold of AM frequencies now. We
already have succeeded in this field as we presently have a provisional license
for even a very high-power one at 216 on the dial. We shall stick to it with
vision and enthusiasm, not forgetting the business aspects, and will by no
means abandon the project. In the coming years this broadcast channel will be
immensely valuable when broadcasters and investors realize the potential of
Digital AM. Regarding the strategic challenges on the table before us there are
ways round most problems. If the authorities should decide to revoke the
current license, we will also continue our project, as there are many
possibilities for AM-broadcasting in the years to come.
We think that there are always possibilities in a
promising process and hope a serious and strong investor also will see it that
way. We feel our opportunity should be very interesting.
Svenn Martinsen
Chairman
1000@northernstar.no