PDS_VERSION_ID        = PDS3                                                  
RECORD_TYPE           = STREAM                                                
OBJECT                = TEXT                                                  
  INTERCHANGE_FORMAT    = ASCII                                               
  PUBLICATION_DATE      = 1997-07-24                                          
  NOTE                  = "Internal memo describing system temperature        
                           measurements which included cases in which         
                           the Moon either filled or partially filled         
                           the beam at DSS 43.  Since DSS 43 data are         
                           not included in this archive, the results          
                           are not directly applicable."                      
END_OBJECT            = TEXT                                                  
END                                                                           
                                                                              
                                                                              
                                                                              
                         CENTER OF MOON CALIBRATION                           
                                                                              
During 41000004 the DSN antenna was accidently moved to the center of the     
Moon for about 2 minutes.  This turns out to be fortuitous because it gives   
us a different calibration in the middle of the run.                          
                                                                              
From 30-second average spectra, we computed the noise power in region of the  
spectrum where there was no signal.  This was done using 41000004 data that   
had been passed through first-order steering.  So the carrier was reasonably  
stable, but the filter roll-off and echo signal were still wandering.         
                                                                              
We found three regions that were "clean" during the 16 minutes of data.       
These were bins 1-50, bins 400-500, and bins 900-1024.  The power in these    
windows was averaged over frequency and over time (the first 26 30-sec spectra
plus the last for target tracking, and spectra 28-30 for center of the Moon;  
spectra 27 and 31 were during transitions to/from the center of the Moon).    
                                                                              
The average powers did not vary much among the frequency windows -- suggesting
that our equalization process is working reasonably well.  There was also not 
a lot of variation over time -- the first spectra gave noise powers that were 
perhaps 3% higher than spectra just before and just after the switch to center
of Moon (in both polarizations.                                               
                                                                              
One surprising result was that the ratio of on-center to on-pole powers was   
different for the two polarizations.  The ratio was about 2.36 for RCP and    
2.56 for LCP.                                                                 
                                                                              
                                                                              
Channel   Frequency      Average Noise Power    Average Noise Power   Ratio   
             Bins         Pointing at  Pole     Pointing at  Center           
-------   ---------      -------------------    -------------------   -----   
 1-RCP       1-  50            367.5034               866.2796        2.357   
 1-RCP     400- 500            366.2967               863.5711        2.358   
 1-RCP     900-1024            367.8012               866.5692        2.356   
                                                                              
 3-LCP       1-  50            382.7652               984.2006        2.571   
 3-LCP     400- 500            384.9250               982.5955        2.553   
 3-LCP     900-1024            384.7310               987.4199        2.567   
                                                                              
                                                                              
                                                                 RAS/970724