Trans World Radio (TWR) is planning to modify the antenna of its 1000 kW transmitter at Roumoules in Southern France to provide a stronger signal in Morocco, Algeria and Tunisia. The current omnidirectional antenna on 1467 kHz will be converted to a directional antenna at a cost of US$200,000. TWR’s John Summerville says the change has the potential of reaching 15 million new people in Arabic and four different Berber dialects.
(Source: Mission Network News)
on Jun 10th, 2008 at 09:45
They usually broadcast to Europe in English at 23:15UK time(00:15CET) using that transmitter which is picked up well in the UK(I regularly listen on 1467kHz/205m MW at that time). Will this mean UK listeners will get a poorer MW night signal because it’s going onto a directional beam?
on Jun 10th, 2008 at 18:13
Yep.
on Jun 10th, 2008 at 22:18
Since when is the Roumoules mediumwave antenna non-directional? See http://pagesperso-orange.fr/monte-carlo-radiodiffusion/anglais/omanR.htm
I have no current technical schedule for TWR Europe at hand, but the ones from recent years showed the various directional patterns as well. Also listening observations clearly confirmed the beam switches (obvious by signal strength changes), indeed with a carrier break of no more than a few seconds.
It should be also noted that the Roumoules mediumwave facility has been built specially for TWR, but it is owned and operated by Monte Carlo Radiodiffusion, which nowadays belongs to the TDF group. MCR already leased airtime on this transmitter to a third party, in particular Radio Vatican which was on air via Roumoules from 2001 til 2006. These discontinued Radio Vatican relays are not to be confused with the daytime use of 1467 kHz from the Col de la Madone transmitter, since last November with the French Radio Maria.
on Jun 11th, 2008 at 06:17
TWR are changing the MW antenna from a 360deg omnidirectional one to a highly directional one to more serve Morocco,a
Algeria and Tunisia than Europe. This will spoil MW reception for UK and European listeners on the frequency of 1467kHz/205m MW in western,northern,eastern and southern europe as they will get a poorer signal and a poorer level of reception due to the directional nature of the new antenna.
on Jun 11th, 2008 at 09:02
Kai,
You may be right. I had always assumed the antenna was directional, but the story says “The solution: change the configuration and the reach of their radio signal from an omni-directional, semi-circular one, to a directional one.”
Maybe the report means that that the antenna pattern is omnidirectional *for these particular transmissions* and they are now adding a new beam.
on Jun 12th, 2008 at 20:15
I just checked out the hand-over from Czech to Kabyle at 1945 UT: After one stroke of TWR interval signal the carrier was cut and returned after four seconds, but noticeably weaker. By the way, another, remarkably strong signal is on 1467 kHz as well, about 10 Hz apart from Roumoules, so after the switch anything turned into an unintelligible mess of fast subaudible heterodyne. The four seconds in the clear were just not enough to identify the other signal, but perhaps it’s the unid. Saudi transmitter, listed in WRTH?
So the antenna configuration with switchable patterns is still the same. A possible explanation can be found when putting every word of the Mission Network News article on the gold-scales as German saying goes. It speaks about a “semi-circular” configuration, i.e. not fully circular, and this could be meant as a somewhat exaggerated paraphrase for the quite broad pattern, covering the area from Tunisia up to Spain, which is in use for Arabic and Berber languages.
So it appears that the plan calls for modifications that will create a narrower pattern with more gain, by changing the configuration of the phasor system accordingly. Concerning the broadcast in English (and the ones in Czech and Slovak as well): They would be affected only in case the modifications remove the other patterns.
on Jun 12th, 2008 at 21:19
Thanks for your research, Kai. We have to remember that Mission Network News is not aimed at people with technical knowledge, and I doubt the writer has that knowledge either. The only question I have is: surely the modification you suggest wouldn’t cost $200,000 ? Whatever they’re planning, it sounds expensive to me.
on Jun 17th, 2008 at 12:35
Apparently I got an email from TWR-UK regarding the transmitter conversion; they say that they are only putting up an extra antennae on the mast specifically targeting North Africa and it won’t affect listeners to the nightly English language programme in Europe as they will still be putting out a fully omnidirectional signal for Europe and the UK still using the omnidirectional antennae on 1467kHz/205m MW for the 23:15UK(00:15CET)/22:15UTC nightly transmissions
on Aug 14th, 2008 at 11:53
Dear All,
The MW transmitter in Roumoules - dpt 04 in France - using 1000 kW during evening hours, is already linked to a directional antennas system.
6 pylones allow to radiate power in 5 different directions : UK, Germany-Scandinavia, Eastern Europe, South-East Europe (Italy, Greece), South-West Europe & North Africa.
If you observe the transision period between the end of the Czech programm and the beginning of the Arabic program for example, the interval is very short, a few seconds, which corresponds to the change of the direction of the antenna; same story between Arabic and English programm later in the evening. Listeners in UK should observe a stronger signal when TWR is in English than in Arabic.
This means that the antenna is well DIRECTIONAL and not OMNIDIRECTIONAL;
the power remaining the same.
So….the antenna system is already a directional system - not a omnidirectional antenna system and maybe TWR would like still a better beam system with much gain ?
Please note that during daylight hours - 05.00-18.00 UTC - 1467 kHz is used from Col de la Madone - MONTE CARLO DIFFUSION MW site - 15 km north of Monaco,
with a power of 50 kW into an OMNIDIRECTIONAL ANTENNA - with the religious program of Radio Maria in French.
Best regards,
Dom
on Aug 14th, 2008 at 12:03
Hello again,
Sorry, this is more precise information than before:
In 1987 for the mediumwave frequency 1467 kHz, which was before transmitted from a transmitter at La Madonne, a switchable directional antenna consisting of 5 ground-fed guyed masts was built. This antenna allows a switchable directional radiation in the following directions:
Destination Azimuth
Scandinavia 25°
Eastern Europe 85°
Italy and Greece 150°
Spain, Portugal, Northern Africa 241°
UK 325°
The action for changing the direction lasts only 5 seconds. Remarkable is, that there are no helix buildings at the basements of the masts used for mediumwave transmission and that the devices for tuning the masts to the transmission line, which is as that of the longwave transmitter built as overhead line, are placed in the open air.
The mediumwave transmitter of Roumules transmitter has an output power of 1000 kW. It is also used for transmitting the religious program of Trans World Radio. In opposite to the longwave transmitter, which can be received at day- and nighttimes well in Southern France, Northern Italy, Switzerland and Southern Germany, this transmitter cannot be normally received well in areas more than 100 kilometres away from Roumoules. However at nighttime its waves may have because of its excellent skywave propagation at least the same range as those of the longwave transmitter.
Best regards,
Dom
on Jun 7th, 2009 at 11:09
This antenna upgrade at Roumoules completed April 9, 2009 according to this news item on TWR website:
http://www.twr.org/news/twr_announces_antenna_upgrade_north_africa
However, I presume power stated below should be 1,000 kW (not 100 kW)?
.
TWR Announces Antenna Upgrade
Trans World Radio (TWR) is pleased to announce the successful completion of
a major antenna upgrade to North Africa as of April 9, 2009. The upgrade
greatly improves both coverage and signal strength, increasing the number of
potential listeners in the region to 40 million people.
Prior to the antenna modification, TWR\’s signal to many North African people
groups, particularly those in the Northern Atlas mountains, was nearly
indistinguishable above the interference caused by electromagnetic radiation
from growing cities. Today, the reception is loud and clear. The
transmission is now beamed towards the Atlas Mountains in a concentrated
beam, as opposed to the earlier, wider-angle signal toward an area with not
much interest in reception. The transmitter power for 1467 kHz remains at
100,000 watts.
One North African listener says, \
on Jun 19th, 2009 at 08:31
It is correct, that this project completed at 09 April 2009. It is also correct, that the power is 1000 kW and not 100 kW.
Kind regards,
Bernhard