On 7/23/18 5:56 PM, Tim Shoppa wrote:
I thought the thinned array curse was specifically referring to
transmitting coherent arrays?

In terms of synthetic aperture receiving arrays, I'm not sure the absolute
timestamping accuracy you can extract from say, the on-off encoded minute
marker on the 60kHz reference signal will be good for much of any synthetic
array used at HF or above. I'm guessing their transmit antenna has a Q of
100 or so, meaning that the on-off encoding will have a rise or fall time
in the millisecond ballpark.

Wikpedia tells me NPL used to have a "fast code" 100 bit per second signal
which would imply that their antenna Q is not more than 1000.


Why not use GPS to get your sync?
Using some sort of VLF, LF or HF signal seems subject to propagation uncertainty which would be greater than the few ns you could get with disciplining a decent oscillator with GPS.

In practice, what you probably want to do is have a pilot tone you can distribute across your array.





Tim N3QE

On Mon, Jul 23, 2018 at 3:41 PM, Andre <an...@lanoe.net> wrote:

Hi, has anyone ever combined an SDR and Anthorn atomic clock receiver
module so that they can be synchronized?
the idea here is as a variant of a thinned array similar to WebSDR but
using lots of smaller units to get around the thinned aray curse (tm)
and combining signals with suitable offset delays so that signal increases
at the expense of noise.

-Andre


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