[Laser] Lunar Eclipse

[F1AVYopto at aol.com]

Jim,
I tested your entire sound file with my  best Spectran settings and I find 
with no doubt a very thin line at 300  Hz.
The 100 Hz line is not viewable but seems "suspected" at some  moments.
It is normal the 300 Hz is well stronger because with a perfect  equilibrated 
three phased network the 100 Hz is cancelled.
This 300 Hz line  is only 2 to 5 dB above the background noise in a 0.084 Hz 
bandwidth !
It is  about the same level we found with Marius F8DO on the 120 / 360 Hz 
lines from  France during our April lunar eclipse.
Your 60 Hz line seems very strong that  means probably a spurious coupling 
injection.
To avoid this problem we use an  audio transformer to isolate the coupling 
loops between the optical RX and the  PC.
The optical RX frame and the 0V RX PSU (via separate 12V battery) is  
grounded by a 30 cm iron picket only at the RX side.
To detect so small  levels each details able to reduce spurious extra noise 
are very important.
I  have tested all the possible lines that could be generated by my local 50 
Hz in  the the PC sound card during your file to FFTSDP waterfall convertion.
I  found no lines on 50 150 200 250 350 Hz that is encouraging for the result 
 validity ?
We look forward to your reports with our Spectran parameters and  with your 
PCs on this same file.  
The graph picture I got with your  sound file can be found at :   
http://pageperso.aol.fr/F1AVYopto/Europe+lights.jpg
73 Yves F1AVY