Sept 27 2004


  Hello, all,

  Here are my SSB parameters:

  First FFT bandwidth (Hz) [83]
  First FFT window (power of sin) [2]
  First forward FFT version [0]                [SM5BSZ:  Change to 5 ( much faster )]
  First FFT storage time (s) [1]               [SM5BSZ:  Change to 10 ( unless you have small memory, Allows 
  First FFT amplitude [1000]                                            longer averaging times )]
  Enable second FFT [1]                   
  First backward FFT version [0]               [SM5BSZ:  Change to 1  is much faster but with Linrad-01.26 there will be             
  Sellim maxlevel [6000]                                 advantages of using floating point Linrad-01-25 and earlier, best use 1 here]
  First backward FFT att. N [6]
  Second FFT bandwidth factor in powers of 2 [2]    [SM5BSZ: Change to 0 or 1. Typicaly no need for narrow filtering in waterfalls for SSB]
  Second FFT window (power of sin) [0]              [SM5BSZ: Change to 2. Provides better filters] 
  Second forward FFT version [0]                    [SM5BSZ: 2 is much faster, but with Linrad-01-26 there will be advantages of using 
  Second forward FFT att. N [7]                                                floating point]
  Second FFT storage time (s) [5]  
  Enable AFC/SPUR/DECODE [1]                        [SM5BSZ: Use 1 here only if you actually want to use spur removal. AFC should not be
  AFC lock range Hz [150]                                                     used for SSB so make the window small and make it inactive on screen]
  AFC max drift Hz/minute [100]
  Enable Morse decoding [0]
  Max no of spurs to cancel [100]
  Spur timeconstant (0.1sek) [5]
  First mixer bandwidth reduction in powers of 2 [4]
  First mixer no of channels [1]
  Baseband storage time (s) [200]          [SM5BSZ: !!! Use much smaller time here. At high bandwidth this would require very much 
                                           memory. Many arrays are allocated in the baseband for CW decoding. The are useless in SSB mode
                                           but I have not removed memory allocation in ssb mode yet.
                                           In cw with a bandwidth of 50Hz or less, the sampling speed is very low and this is no problem. ]
 
  Output delay margin (0.1sek) [5]         [SM5BSZ: Maybe you can make this smaller. Check the margin with 'T' ]
  Output sampling speed (Hz) [10000]  
  Default output mode [1]
  Audio expander exponent [3]
  A/D speed [96000]
  Check [1110107]

  
  -----end of SSB parameters
 


  Here are my wcw parameters:

  First FFT bandwidth (Hz) [100]
  First FFT window (power of sin) [3]
  First forward FFT version [2]
  First FFT storage time (s) [20]
  First FFT amplitude [1000]
  Enable second FFT [1]
  First backward FFT version [1]
  Sellim maxlevel [6000]
  First backward FFT att. N [6]
  Second FFT bandwidth factor in powers of 2 [4]
  Second FFT window (power of sin) [4]
  Second forward FFT version [2]
  Second forward FFT att. N [10]
  Second FFT storage time (s) [15]
  Enable AFC/SPUR/DECODE [1]
  AFC lock range Hz [150]
  AFC max drift Hz/minute [100]
  Enable Morse decoding [0]
  Max no of spurs to cancel [100]
  Spur timeconstant (0.1sek) [5]
  First mixer bandwidth reduction in powers of 2 [4]
  First mixer no of channels [1]
  Baseband storage time (s) [150]
  Output delay margin (0.1sek) [5]
  Output sampling speed (Hz) [6000]
  Default output mode [1]
  Audio expander exponent [3]
  A/D speed [96000]
  Check [1110107]

  Change only between brackets.
  
  If file has errors, Linrad will ignore file and prompt
  for a complete set of new parameters

  linrad-01.25

  With the SSB parameters I get a delay on the order of 0.5-0.7 seconds or  less.  I am not sure of 
  the delay with the CW parameters listed above, as  I didn't check it today, but generally I have 
  had delays of 2-5 seconds  [which are not a problem for my purposes].

  I post them with no representation as to their optimization.  Rather, they  are being posted to 
  provide an object for criticism, and to provide a  framework for the discussion of the tradeoffs 
  and consequences of specific  parameter choices.

  These are running on this system:

  CPU::  Pentium 3
  CPU Speed::  1 GHz
  RAM in MB::  770 MB
  SOUND CARD::  M-Audio Delta44
  SOUND DRIVER::  OSS/Linux OSS 3.99.1g
  ADDITIONAL CARD1::  SoundBlaster PCI
  VIDEO CARD::  ATI Radeon 7000
  VIDEO DRIVER::  Rage 128
  LINUX DISTRIBUTION::  Red Hat
  LINUX VERSION::  8.0
  KERNEL VERSION::  2.4.20-28.8
  GCC VERSION::  3.2 20020903
  SVGALIB VERSION::  1.9.19
  LINRAD VERSION::  01.25

  Hope that is of some interest, and

  73, Roger Rehr, W3SZ
  
  http://www.qsl.net/w3sz



                         -------------*********-----------------

   Oct 14 2004


  Hello, All!

  This is just a brief report on my experience with Linrad in the EME  contest this past weekend.  
  I have used Linrad each year beginning in 2000  for the annual ARRL EME contest.  For the last 
  several years it was my  primary receiver.  But this weekend, the first leg of the 2004 ARRL 
  EME  Contest, was the first time that I used it for EME with the  Antennspecialisten Linrad 
  hardware.  Like last year, I did not even have a  conventional receiver online.  Linrad was it 
  and nothing else was needed.

  I was very pleased and impressed.  I worked only CW for the contest, but I  did take some time 
  out to go up above 144.100 and listen to some EME JT65b  using Linrad and the Antennspecialisten 
  hardware as the front end for  WSJT.  What were the advantages of using Linrad in this manner? 

  [1] I could immediately see any JT65b station that came on the air over a 96 KHz  frequency span. 
  [2] I could take advantage of Linrad's noise reduction. 
  [3] The Linrad waterfall was  superior to Spectran's in my hands for seeing  the stations.
  [4] Using Linrad's click and point frequency control, I was  able to set, immediately and with no 
     trouble, the receive frequency so  that there was zero frequency offset for WSJT to deal with.
  [5] The receiver seemed very sensitive and I had no dynamic range problems.

  On cw, I found [as before] that quite a number of stations that I heard  very clearly with Linrad 
  replied with 'QRZ' for a long time [sometimes  forever] to my calls.  That tells me that Linrad 
  with the  Antennspecialisten hardware hears very well.  I also found that when I  called CQ, 
  I was able to work the station calling me every time.  So I  believe I heard everyone who called me, 
  but not everyone whom I heard  clearly was able to copy me.  I was running 1500 watts, and 
  my 2 x 2  2mxp32 array has a theorerical gain of 21.8 dBd, so I had a reasonable  ERP.  I could see 
  and hear my own echoes with no problem.  Using Linrad, I  was clearly 'transmitter limited' in 
  terms of making contacts.  This is  where I want to be.

  I kept the 'smart' and 'dumb' noise blankers on [manual] nearly the whole  time, and I was not 
  bothered by noise.  When I turned them off I was  reminded that when my rotors are rotating they 
  generate a lot of noise,  totally obliterating the EME signals.  Their noise had been totally  
  eliminated by the noise blankersa and as I was never looking at the  wideband spectrum while 
  operating the rotors, I had been oblivious to the  noise.

  My cw parameters gave me a 5.3 second receive delay, which was not a  problem for me.  I learned 
  to watch the wideband spectrum as 'the end of  the minute' approached, and to start transmitting 
  when the spectral peak  of the station I was working disappeared.  

  These parameters were:

   First FFT bandwidth (Hz) [100]
   First FFT window (power of sin) [3]
   First forward FFT version [5]
   First FFT storage time (s) [20]
   First FFT amplitude [1000]
   Enable second FFT [1]
   First backward FFT version [1]
   Sellim maxlevel [6000]
   First backward FFT att. N [6]
   Second FFT bandwidth factor in powers of 2 [5]
   Second FFT window (power of sin) [2]
   Second forward FFT version [2]
   Second forward FFT att. N [10]
   Second FFT storage time (s) [20]
   Enable AFC/SPUR/DECODE [1]
   AFC lock range Hz [150]
   AFC max drift Hz/minute [100]
   Enable Morse decoding [0]
   Max no of spurs to cancel [0]
   Spur timeconstant (0.1sek) [5]
   First mixer bandwidth reduction in powers of 2 [4]
   First mixer no of channels [1]
   Baseband storage time (s) [100]
   Output delay margin (0.1sek) [5]
   Output sampling speed (Hz) [6000]
   Default output mode [1]
   Audio expander exponent [3]
   A/D speed [96000]
   Check [1110107]



  My parameters for JT65b [ssb mode] were:

   First FFT bandwidth (Hz) [83]
   First FFT window (power of sin) [2]
   First forward FFT version [5]
   First FFT storage time (s) [10]
   First FFT amplitude [1000]
   Enable second FFT [1]
   First backward FFT version [1]
   Sellim maxlevel [6000]
   First backward FFT att. N [6]
   Second FFT bandwidth factor in powers of 2 [2]
   Second FFT window (power of sin) [2]
   Second forward FFT version [2]
   Second forward FFT att. N [7]
   Second FFT storage time (s) [10]
   Enable AFC/SPUR/DECODE [1]
   AFC lock range Hz [150]
   AFC max drift Hz/minute [100]
   Enable Morse decoding [0]
   Max no of spurs to cancel [100]
   Spur timeconstant (0.1sek) [5]
   First mixer bandwidth reduction in powers of 2 [4]
   First mixer no of channels [1]
   Baseband storage time (s) [10]
   Output delay margin (0.1sek) [5]
   Output sampling speed (Hz) [10000]
   Default output mode [1]
   Audio expander exponent [3]
   A/D speed [96000]
   Check [1110107]

  The delay using these parameters was less than one second.

  I played around with the CW parameters to get good performance with  reasonable delay times, but 
  I did not play around with the SSB parameters  as I didn't need to do so.

  For the second leg of the contest I am going to actually hook up a  conventional receiver, so that 
  I can again directly compare the Linrad  software and hardware to the conventional receiver, much 
  as I did in 2000  and 2001 when using my own front end.  I am doing this out of curiosity,  not 
  because I need anything besides Linrad.  I will be using an SSB  Electronics LT2S-Mk V along with 
  either my Elecraft K2 or my FT1000MP.  If  I get the narrow roofing filter for the MP in time, 
  it will be the one I  use.

  I can't wait for the second leg of the contest.  The combination of the  Linrad hardware and 
  software made this EME contest the most enjoyable one  I've had since my first getting on EME in 
  1998, and I can't wait to spend  another EME contest weekend with the combination.

  The Lin-2-1000MP add-on to make a Linrad transceiver out of my FT1000MP  and Linrad worked fine 
  except for those occasions when I forgot to type  'q' to bring the MP on-frequency before 
  transmitting.

  73,

  Roger Rehr,  W3SZ