How to listen to FDM
V. 1.0 - 22.09.2003
Copyright (C) 09/2003 by Howard Fuhs
One little example on how to listen to exotic modulations without the proper and expensive equipment shall be given here. I want to note that this is a quite old example which was already mentioned in several magazines for scanner hobbyists. Furthermore it is valid for an analog modulation type which is today more and more substituted by digital modulation types.
This example shall give you an idea on how the guys in the underground are working and thinking.
FDM stands for Frequency Division Multiplex.
Single signals will be put into groups of 3kHz wide SSB signals (USB and LSB). Space between two signals is 4 kHz.
Connect the Baseband Video-Output of an analog satellite receiver to the antenna input of a good shortwave receiver. Analog satellite receivers are available for a nickel or a dime on flea markets and ham fests.
Search with the sat-receiver for a FDM transponder. A transponder using FDM can easily be recognized through the "pattern picture" it gives on a tv screen compared to the normal grey/white snow diplayed if no signal at all is available.
Once a FDM transponder is found tune your shortwave receiver between 10 kHz and 5 MHz in USB and LSB.
ARABSAT (C-Band) offers the fastest success.
I invite your suggestions for revising this document. I plan to review and revise this document as the need arises.
Copyright (C) 09/2003 by Howard Fuhs
All Rights Reserved!