Elad Fdm77 Hf Receiver Operating Manual

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                  Mode A CW demodulation using BFO for 800 Hz audible tone.  
 
 
                Mode A CW demodulation using BFO for 1.100 Hz audible tone.  
    
						

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Mode B CW demodulation with fixed BFO and Zero beat. To hear the 800 Hz   
A udible tone a different VFO tuning will be required.  
   
3.5.5 AGC Operation & Control  
  
The  operator  is  allowed  to  work  with  Automatic  AGC  (  Slow  or  Fas t)  or  with  Manual  AGC.  
When working with Manual AGC the gain is varied through the slide bar control.  
  
3.5.6 Using the Notch function.  
  
The  filter  control  section  includes  the  possibility  to  use  two  notch  each  one  with  the  a  variable 
BW.  Each  notch  is  selectable  by  clicking  on  the  relevant  button.  Notch  1  is  placed  on  the  pass 
band  by  left  clicking  with  the  mouse  on  the  spectrum  scope  and  notch  2  by  ri ght  clicking.  Fine 
tuning of the notches position is allowed through the up and down little ar rows at the right side of 
the notch buttons.  
   
						

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                      Desired signal at 1.125 HZ with two interfering tones (750 Hz and 1.500 Hz).  
 
 
                      Thanks to filter notch 1 the interfering signal at 750 Hz has been eliminated.  
      
						

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Using the notch filters. 
 
 
                  Thanks to filter notch 2  the interfering signal at 1.500 Hz has been eliminated.  
 
 
                  Both interfering signals have been eliminated using notch 1 and 2  
      
						

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3.5.7 Audio spectrum and audio oscilloscope. 
 In addition to the 12KHz input signal also the demodulated audio signal can be displayed on a  
level/frequency diagram in the lower left side of the advanced window and in a level/t ime diagram 
i n the lower right side.  
  
3.6 Main SETUP  
In  the  window  TUNING  of  the  cockpit  the  button  SETUP  allow  to  enter  the  MAIN  SETUP 
function. Just click the SETUP button and a new window “MAIN SETUP” w ill popup to allow the 
setting of :  
 
 
  
Stand Alone  operation  of FDM -77. (This is the normal operating condition)  
TCP  Client/Server .  This  mode  allow  the  remote  control  of  FDM -77.  The  PC  where  ELAD 
software is installed  can be configured as server (with the FDM 77 connected) or client (as remote 
station).  
DEMO  mode   operation  of  FDM -77.  It’s  a  demonstration  mode  to  show  the  main  features  of  the 
ELAD  software  radio  even  if  the  Hardware  RF  front -end  is  not  available).  When  using  the  demo 
mode some test signals can be selected through the “Choose File” windows.   
USB  mode .  (This  is  the  normal  operating  condition  with  the  Hardware  RF  front -end  connected  to 
the PC through the USB port).  
Demodulation 12 KHz.  Check this option only  if you want to use the software with down -
converters to 12 KHz  ( as the ELAD 45512 or 10712 models).     
						

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Choose Dev In/Out. If you have two sound cards installed in your PC the selection of the car d you 
want to use as input (Recording mixer) and output ( Speaker Mixer) device is allowe d. 
Choose file.  The selection of a test signal to be used in demo mode is allowed.  
Flip  input  spectrum.  To  be  used  with  down -converters  only  and  when  a  spectrum  inversion  is 
observed on the Spectrum & Scope Viewer. Not checked is the  Default .  
Calibration.  This is a facility provided to help the operator in setting the corre ct input level of the 
sound card. Please refer to section 5 of this manual to understand the use of this fac ility. 
Enable  ELAD  Virtual  Cable .    If  you  want  to  use  third  party  application  to  decode  special  modes 
that  use  a  sound  card  as  decoder  you  should  enable  this  function.  In  the  nor mal  operation  with 
FDM77  the  PC  sound  card  is  used  to  filter  and  demodulate  the  received   signals  and  can’t  be  used 
also  to  decode  RTTY,  HamDRM  or  CW  with  dedicated  applications  as   CWget,  MMTTY,  Jfax  . 
Thanks  to  the  ELAD  virtual  cable  driver  (supplied  with  ELAD  Softw are  radio)  the  signal 
demodulated through the PC sound card is then fed to the ELAD virtual cable ( WINDOWS se e this 
driver as a sound card) to be decoded with the above mentionad external appl ications. Of course the 
external  application  should  be  configured  with  the  ELAD  virtual  cabl e  as  recording  device  in  the 
Mixer setting.  
Enable  output.   To  disable  the  output  from  the  sound  card  to  the  speakers.  The  default  of  this  is 
enabled.  If  you  foresee  to  use  third  party  application  to  decode  special   mode    (  for  example 
Hamdream or Windrm) you should disable this function in order not to have the  electrical sound of 
the demodulated signal reproduced by the speakers.  
  
Colour . ( to choose the colour of the cockpit).   
  
Important Note: With WIN2K operating system and when decoding the DRM signals with an  
external application you must close the external application before changing the re ception mode. 
This is due to the limitation of WIN2K in handling two applications running on the same sound 
card. If you use the DRM internal application closing it to change the reception mode is not 
necessary.   
   
      
						

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3.7 AF Control. 
  
In  the  lower  right  side  of  the  cockpit  the  AF  CONTROL  window  all ow  to  set  up  the  sound 
reproduction that best conforms the operator preferences. The AF f requency spectrum is divided in 
6  octaves  with  high/low  tone  slide  bar  controls.  Moreover  volume  control  i s  added    with  mute 
control (toggle button). This volume controls the out level to the sound boar d. The operator should 
set  the speaker volume through the WINDOWS mixer control of the sound card.  
 
 
  
The  Pag     and  Pag  keys  on  the  PC  keyboard  can  be  used  as  a  shortcut  to  control  the  out  level  to 
the sound card.    
						

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4. Remote control of FDM -77.  
This function is not released so far. It consists of an option (not included in the FDM77, but  
available as separate option) to allow the remote control of a receiving stati on equipped with 
FDM77 (Server station) through internet (TCP/IP) simply using a PC with the ELAD S oftware 
radio installed (Client station).  
The client station can control the remote receiver and have the audio stream  reproduced simply 
using WINAMP.  
More details will be available later on our site 
www.eladit.net   
      
   
						

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5. PC sound card mixer setting. 
In order to get the  best performances a proper setting of the sound card Mixer must be done.  
  
Open the mixer and disable the mike and line as inputs for the speakers.   
 
 
  
Wave and Volume only should be enabled for sound reproduction.  
 
 
  
Open the mixer and enable as recording input the line input.   
    
						

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The recording level must be adjusted carefully in order to have a good decoding of  DRM and a ll 
the analogical mode CW, SSB, AM and FM.