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Size That Matters


smI think we all agree that fairness should be uphold in any attempts to reveal historical facts. It goes the same with Radio Malabar that was said by cdvandt.org as “Worlds most powerful arc transmitter ever”. I kinda turn that someway for the tag of this site: “digital archeology of the biggest transmitter ever”. Now, the question is: was it really that powerful ? that big ? I have read two books on the history of Wireless Communication (I am going to mention the titles on the next entry of this site) and there’s no mention whatsoever about Radio Malabar. I browse through and search using Malabar, Dutch Indies, Netherland, Indonesia, de Groot, etc: all come with no result. Has Radio Malabar been ignored in the history of wireless communication ?

Perhaps it’s gonna take more than just two books to answer the question. However it is imperative for me now to reveal anything matters with its size. I could have been straight with the data, but since the source is in Dutch, my chance is only by using Google Translate which more than often resulting nothing but gibberish. So, what I do is to present the original text I got from this site. OK, I could just make a guess from the English translation, but for the sake of accuracy I would just leave it original. I wish someone with fluency in Dutch could translate it … :(

Het idee van een rechtstreekse verbinding tussen het voormalig Nederlandsch Oost-Indië en het Moe- derland is in 1916 ontstaan in de vorm van een dissertatie van Ingenieur de Groot. De eerste luister- proeven vonden plaats met geleende Telefunken-ontvangers. Na bevredigende resultaten bij de ont- vangst van verschillende Europese en Amerikaanse zenders werden besprekingen gevoerd over geschikte frequenties en zendvermogens. Teneinde meer gegevens te verzamelen begon men met proefuitzendingen met een 100 kW Poulsen-Vonkenzender van de Federal Telegraph Company enmet een provisorische antenne aan een ballon bevestigd. Het bleek dat de resultaten echter niet bevre- digend waren, zodat dr. De Groot – die met de onderzoekingen belast was – een reusachtige kloof in het bergmassief uitkoos van de Goenoeng Malabar met 2 berguitlopers als natuurlijke ophangpunten voor zijn antenne. Als stroombron diende de enige reserve-dynamo van de Bataviasche Tramweg My (beschikbaar gesteld door OM v.d. Horst, redactie PK-jaarboek ’82); aangedreven door een 125 pK sterke vliegtuigmotor van de Militaire Aeronautische Dienst.
Dr. De Groot had inmiddels een gigantische vonkzender van 2400 kW vermogen geconstrueerd. Al- leen al het gewicht van de magneten bedroeg meer dan 180 ton, het spoelenmateriaal ongeveer 20 ton. Een groot koelwaterbekken voor het hoofdgebouw in de kloof diende voor afvoer van de warmte. De voor de zender benodigde waterstof werd in elektrolytische waterstofgeneratoren gemaakt. De zendfrequentie was 15.600 meter; het golfbereik lag tussen 7800 en 18.000 meter. Dit zen- dertype werd in dubbele uitvoering geïnstalleerd en verder met ,,kleinere” zenders aangevuld. Zo werden er nog twee lichtkogelzenders van ieder 200 kW vermogen geplaatst, evenals een Telefunken- machinezender van 400 kW vermogen.
De nieuw geconstrueerde antennes hadden eveneens geweldige afmetingen. De grote langegolf-an- tenne werd door 5 over de kloof gespannen duimse stalen kabels van wel zo’n 2000 meter gedragen. De ophangpunten op de beide uitlopers van de Goenoeng Malabar bevonden zich ongeveer 900 meter boven het station. Vijf door motoren aangedreven lieren aan de zuidzijde, en overeenkomstige toe- standen met tegengewichten aan de noordelijke, dienden tot het constant houden van de trekspanning van 10.000 kg. De eigenlijke antennedraden bestonden uit met koperdraad omwikkeld non-ferro dra- germateriaal van 7/8 duimsterkte. Door het hiermede bereikte grote oppervlak kreeg men te maken met corona-effecten. De bevestiging aan de dragerkabel vond plaats op 700 meter hoogte middels 2 meter lange isolatoren.
Op 5 mei 1923 werd het bedrijf officieel geopend. Desondanks werden niet alle verwachtingen ver- vuld, hoewel naar vele landen kontakten konden worden gelegd.

Should there be anyone out there capable of translating the above text in good English, please do that in the comment section (click “leave a comment” of this entry). Thanks!

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  1. Gamal Soegiono
    06/09/2012 at 5:23 pm

    For your convenience, here a close translation of the dutch text:

    The idea of a direct (radio-) link in between former Netherlands India
    and its motherland evolved in 1916 as a disertation of (dutch
    Telecommunication-) Engineer de Groot.

    First receiving test took place using rented Telefunken receivers.
    After gaining satisfactory results, by receiption of several european and
    american transmitters, further test were conducted regarding optimum
    frequencies and required transmitting power.

    In order to gain more facts, first transmission tests were conducted
    using transmitting power of 100kW.

    An arc transmitter of the Poulsen-System was connected to an provisory
    antenna, suspended from a ballon carrier.

    The results gained, were unsatisfactory, so Dr. de Groot, who was
    involved in those transmission tests, choosed a gorge in the Malabar
    mountain complex, using two offshoots of the mountain as suspension
    points for his antenna.
    [Note: According to Klaas Dijkstra, a technician and employee at
    Radio Malabar, it was in fact planned to put up a ballon antenna but
    never realized. Actual transmission test took place with an antenna
    suspended from mountains.]

    The only spare dynamo of the tramway company of Batavia (provided
    by OM v.d. Horst, author PK-yearbook 1982), driven by an aircraft
    motor of 125HP, lent from the (dutch) airforce.

    Meanwhile, Dr. de Groot outlined an giant arc transmitter of 2400kW
    power capacity
    [Note: This is input power from the power source, not RF output power to the antenna, which may be assumed to be approximately 50% of the input power.]

    Just the mass of the magnet (structure) summed up to 180 tons, the
    coils approximately 20 tons.

    A large cooling water basin at the front of the main building in the
    gorge was to radiate the superfluous heat energy.

    The hydrogen gas needed, was produced by electrolytic hydrogen
    reactors.

    The transmitting frequency [wavelength in fact] was 15.600 meter; the
    working range spread from 7800 and 18.000 meter.

    Two versions of this transmitter were installed and supplemented by
    transmitters of lower power capacity. Two arc transmitters of 200kW
    capacity were erected as well as an alternator type transmitter of the
    Telefunken System with 400kW power capacity
    [Note: This is output power into antenna – in contrast to the arc transmitter type who is nomenclated with input power.].

    The newly constructed antennas had giant dimensions. The large LF
    Antenna was suspended from 5 stranded steel cables of around 2000
    meter length.

    The suspension points atop the offshoots of the Malabar mountain were
    about 900 meters above [the level of] the station.

    Five motor winches on the southern side and corresponding off-stands
    with compensation weights on the northern side where to held the
    [suspension cable] strain constant at 10 tons.

    The antenna conductors consisted of non-ferrous core material of 7/8
    thumb diameter, surounded by copper wire. This [construction] gained
    a relatively large conductor surface to prevent corona effects.

    The attachment with the suspension cables took place at a level of 700
    meters, using insulators of 2m length.

    On May 5/1923 the [public] service opened officially.
    Nevertheless, not all expectations could be satisfied, however
    contacts could be established with many countries.

    [translation 2012 by g_soegiono@yahoo.co.id]

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