Re: FDM and Inmarsat reception.

from: owner-knowledge@drdish.com
Date: Fri, 01 May 1998 16:43:22 +0200
References: <199805011351.PAA32251@europa.glo.be>


> Dear Sir,
>
> I wonder if you could help me with 2 little problems.
>
> 1// I am using an Uniden MST9004P and a Grundig STR400P receiver for
> analoque Ku/C sat-reception.
> Both receivers have no seperate baseband output, wich is essential for
> FDM
> reception.
> Is there any possibility to use one of those two receivers for FDM
> reception ?
> I already tried to connect the video output from the decoder-scart
> connector, with all different modes; clamped, unclamped, ... to my
> short-wave receiver without any result.
> If they are not useable, what cheap low-treshold receiver without
> positioner or polarizer outlets would you advise ?
>
> 2// Is their within the Inmarsat-transmit-spectrum any kind of
> ''order'' ?
> I have been told that marine uses 1530 - 1544, mobile ground terminals
> 1544
> - 1545 and aircraft 1545 - 1548.
> Is this true or false ? If false, do you know where to find what ?
>
> Thank you very much in advance for the reply.
>
> Ivo Van Wolvelaer

Dr.Dish:
FDM-signals are normally found in the c-band. Try INTELSAT 603 on 24.5
degr. west. Here are the traffic between the US and Europe/Africa and
inner-african telecom. You should use a large antenna (> 180cm in your
region) and receiver with lt-function. Strong and Manhattan offer some
cheap solutions or just try to find second hand a SR50 from Echostar.
Connect the baseband ou from the sat-receiver to the antenna-in of a
good shortwave-receiver. Very helpful is is antenna-match between the
two receiver. Sometimes you will need to attentuate the signal by 15 or
20 db. Tune the shortwave-receiver carefully between 0 and around 3 MHz
in ssb. Signalspacing is 4 kHz. Also try ARABSAT!

The INMARSAT layout:
1530-1544: fixed to mobile (exception 1534.350, here you hear mobile to
fixed)
1544-1545: DISTRESS
1545-1548: Aereo (data, digital-tv)

For more information consult the regulary articles in TSI or read the
INMARSAT-story in my book "Satelliten-Signale anzapfen und auswerten"
(ISBN 3-7723-4903-X)

Christian Mass (Dr.Dish)
Senior-Editor of TELE-satellite International
http://www.TELE-satellite.com
Producer of drdish@tv
http://www.drdish.com
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