[600MRG] Quartile Method of Characterizing 630m Propagation Paths: Last Night's Results. End of Part 3.

[James Hollander]

 Part 3B end of post. Thanks for your time.  73,  Jim H  W5EST
 
Too few decodes made the XIQ/XGP path statistics V and T insignificant. Assume reciprocal.    
Direction               Time     Nr   SNRij 3/4   SNRij 1/2    SNRij1/4   V      T   
XIQ  to  XGP 0154-0306    4     -9            -19           -22           10        7  (insignif)    
XIQ frm XGP 0236-1224   6     -18          -19           -19             1        1  (insignif)   
   
 The XJM/XKA path looks rather different each way last night. XKA had less than half the number of decodes that XJM obtained. But XKA decodes of XJM ceased about 7 hours before those of XJM did.  The quartile method yielded quite different V and T each way, but perhaps the quite-different time ranges mattered. So I ran the calculation by restricting the decodes at XJM to those up to 0544Z. The 3rd line of the table shows the result which wasn't too different!  But path reciprocity is usually expected, and the number of decodes is only two or three dozen, so let's suspend judgment.     
    Direction               Time     Nr   SNRij 3/4   SNRij 1/2    SNRij1/4   V      T   
XKA  to   XJM 2256-1304  61     -8            -12            -14           6       2    
XKA frm XJM 2312-0544  33   +11            +8               -4         15     -9    
XKA  to   XJM 2256-0530  24     -4            -8.5            -12          8       1    
    
Now, let's compare two paths from XIQ to XCR and from XXM to XCR on Feb. 9.  This is a path statistics comparison and not a reciprocity test. Why? because these are distinct paths in the same direction.  The path Variability values V are similar, but the dB Tilt values T are quite different, possibly due to low numbers of XIQ decodes at XCR and higher inherent uncertainty in the Tilt.   
   
Direction               Time     Nr   SNRij 3/4   SNRij 1/2    SNRij1/4   V      T   
XIQ  to  XCR 0828-1206   14     -16.5      -23.5          -28           11.5   2.5    
XXM to XCR 0822-1310   65     -16         -19             -27           11.0   -5 .   
    
CONCLUSION:  The quartile method seems to work as expected.  It's easy to use and gives plausible results.  Enjoy! 
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