[time-nuts] Sub mm measurements with gps timing antennas?

Attila Kinali attila at kinali.ch
Wed Apr 25 19:22:51 UTC 2012


On Wed, 25 Apr 2012 15:02:45 -0400 (EDT)
SAIDJACK at aol.com wrote:

> Just brainstorming here, but how about this un-conventional approach:
>  
> Use a CSAC as a precise frequency reference for the LEA-6T. CSAC should  
> operate at <0.12W, I know, that's a lot, but maybe just worth a  try.

Oh.. the CSAC is that low power? I thought they are in the 1W region.
Good to know...
But.. is the CSAC not on the ITAR list? I would expect it to be,
as even some precision OCXO and a lot of MCXO are.

> To make the CSAC work, multiply the 10MHz up to the 26MHz the LEA uses.  
> Then place a small antenna loop around the LEA part to injection-lock the  
> internal 26MHz TCXO to the external antenna. That may work, or not.

I doubt injection locking would work. The LEA modules are quite densly
packaged with lots of ground planes. Very little place where you can
inject anything.

> Or unsolder the LEA-6T metal shield, and remove the TCXO, and replace it  
> with the externally generated stable 26MHz, then re-solder the shield. That's 
>  cheaper than buying 2000pcs reels from uBlox.

I'm not quite sure about this. It would work if we had only to deal with
one or two of devices, but with the numbers we need now, the work would
probably cost more than a reel (i actually don't know what a reel costs,
u-blox has not replied to my request for quotation i placed 3 weeks ago).


			Attila Kinali

-- 
Why does it take years to find the answers to
the questions one should have asked long ago?



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