RE: VLF: TA east to west?

[<hvanesce@comcast.net>]

Repeating (with apologies) and adding to (see last paragraph: wondering about 
Forest/Arlington raw data correlation) a recent message on this perhaps more 
appropriate thread:

Based on Marcus' request for all-day carrier at 17470.1000 Hz and Paul's report 
of -38.55 dB in 1Hz in Forest, Virginia, I'll keep a SpecLab window open at 
17470.1000. 

I installed a receiver with GPSDO at a new lower-noise* permanent location in 
Arlington, VA two days ago but it did not occur to me that the new lower noise 
level might accommodate detection of Stefan's 17470.1000 Hz signal.  
     * (15 dB lower noise so far, additional reduction likely this week)

-38.55 dB in 1Hz would seem to suggest 6 dB in 8 hours using EbNaut, but I 
haven't tried EbNaut and wonder (if the new lower-noise Arlington location has 
noise and path loss similar to that of Forest, VA) how much lower than 6 dB the 
SNR would be with an all-day carrier (instead of with EbNaut).

Does it seem worthwhile to perform 8-hour integrations for (and save raw data 
for) Stefan's 17470.1000 Hz carrier signals in the new Arlington, VA location? 

Any other suggestions for near-term detection of Stefan's 17470.1000 Hz carrier 
signals in Arlington, VA? If EbNaut is strongly suggested, is Windows OS 
incompatible? Long learning curve for an EbNaut newcomer?

Also can't help wondering about some means of correlating Forest and Arlington 
raw data given that most of the noise is likely to be substantially less 
correlated (Forest vs. Arlington) than signal. Daytime DK7FC signal phase 
decorrelation (Forest vs. Arlington) should be less than 100ns rms in 1 second. 
Cultural and sferic noise decorrelation (Forest vs. Arlington) would be much 
greater.  Forest/Arlington separation [not too much, not too little; roughly 
optimum for the tradeoff between (a) differential spheric and cultural noise 
mitigation, and (b) TA phase decorrelation) and geometry (no water or mountains 
between Forest and Arlington; and similar path to Atlantic) of Forest and 
Arlington seem well-suited for differential reception of a DK7FC signal.   
    

73,

Jim AA5BW

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org 
[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Paul Nicholson
Sent: Thursday, December 7, 2017 12:12 PM
To: rsgb_lf_group@blacksheep.org
Subject: Re: VLF: TA east to west?



Ah, ignore the last message.  I just noticed a mistake I made with the sample 
rate!!!

Forest, Virginia gives Eb/N0 = -4.8 dB on the 3 char message, which is -37.30 
dB in 1Hz.

Only something like 1 in 300 chance of that Eb/N0 with random noise.
Combining the two results, this is quite likely your signal.

So, this is looking interesting.

--
Paul Nicholson
--