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Date: Wed, 04 Aug 1999 12:32:34
To: rsgb_lf_group@blacksheep.org
From: "Rik Strobbe" <rik.strobbe@fys.kuleuven.ac.be>
Subject: Re: LF: eclipse
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At 19:50 3/08/99 +0100, G8AFN wrote:
>Is anyone planning any propagation experiments on136kHz or thereabouts
>during the eclipse next week.
>
>I have not yet decided whether to study it, visually or by radio techniques.
>Also if I stay at home (98.5% of totallity) or go receiving portable in the
>far southwest.
>
>I know that the RSGB is involved in measurements on many bands but am not
>sure what exactly is proposed for 136kHz.
>
>Do we know what is likely to happen on our band,  are the changes expected
>to be measurable, what is worth measuring and over what period of time.
>
>I look forward to your comments and advice


I received following information from Jean-Jacques Delcourt, ON5PG: 

    I am working professionaly on the D layer and prepare a doctorate on this
    subject at the Belgian Royal Meteorological Institute.
    I monitor only  time keeping carriers in amplitude,phase and polarization
    below 100 KHz. The best results are from GBR on formelly 16 KHz, but in
    fact around 15,750 KHz which is unfortunately frequency modulated. During
    dusk and dawn, you can see beautiful effects linked with the sun rise,
    the rising of XRays flux and modification of the chemistry of the 
    mesosphere.
    Correlations are made with the XR flux monitoring by GOES satellites. The 
    XR are generated in the sun corona and one of the interests of the aug.11
    eclipse is that during approximatively 2 min, the most part of the corona 
    will be obliterated.
    Phase monitoring is very difficult and requires very stable reference
    oscillators in the range of 10exp-10 on a day. At the lab, I am using a
GPS
    reference with phase locked loop.
    I think that the best way during the eclipse day is testing a circuit
    where the totality path is the middle of the circuit.
    An other way is monitoring 24h on 24h during 3 days [the eclipse day is
the
    second] a carrier with a constant amplitude , the greatest possible.....
    The 5 receivers I use are [all home made] of direct amplification type
with
    crystal filters and bandwidth of 1 Hz ; but I have the greatest interest
    for VLF commercial RX . Data sheets and dealers addresses with prices are
    welcome.
    The antennas are of the loop type [20 spires with the appropriate tuning
    capacitor] mounted inside a water pipe loop to make it inflexible and easy
    to direct.


The frequency range of interest is below 200kHz, preferable even below
100kHz as effects seems to be more explicit on lower frequencies. A
software team from the Belgien amateur radio society UBA has developed a
programme that can be
used to register the fieldstrength measurements. All you need is a PC with
Win95/98 and a soundcard. The audio output of the receiver is fed to the
input of the soundcard. 
More information of about this programme and about the eclipse-experiment
in general can be found at the UBA website http://www.uba.be/ The software
can be requested by sending an e-mail to jacques.debouche@euronet.be with
as subject:
ECLIPSE PROGRAM REQUEST. The required information and calibration-procedure
is included. 
All data can be sent to : 
    John Devoldere, ON4UN 
    Poelstraat 215 
    B-9820 Merelbeke 
    Belgium 
    or via e-mail to john.devoldere@village.uunet.be 

A special award will be issued to everybody who cooperates with the
experiment and sends in his/her set of data. 

73, Rik ON7YD 


Rik Strobbe  ON7YD
rik.strobbe@fys.kuleuven.ac.be
Villadreef 14  B-3128 Baal  BELGIUM   (JO20IX)