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Date: Thu, 7 Dec 2017 12:48:07 -0500
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Subject: RE: VLF: TA east to west?
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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
--