[time-nuts] Low power GPSDO

SAIDJACK at aol.com SAIDJACK at aol.com
Mon Jul 28 17:04:03 EDT 2008

Hello Murray,
no problem :) just wanted to make sure folks know that there are  options 
below 5W out there.
I am impressed with your 50mW TCXO unit. We've been thinking about offering  
DIP14 TCXO's as well on the FireFly. That would allow for true battery  
We are also testing extremely low power (~120mW) OCXO's, with the  heating 
elements integrated into the Crystal Blank itself, but I am not happy  with the 
stability of these just yet.
We also have a Fury GPSDO wired up to the Agilent E1938A - while it's  the 
best Fury I have it's a real power hog. In fact I am having a hard time  finding 
a power supply capable of delivering sufficient warmup current to that  box..
In a message dated 7/28/2008 11:33:44 Pacific Daylight Time,  
Murray.Greenman at rakon.com writes:


I didn't claim that the Trimble NTGS50AA was the "lowest  power GPSDO".
Those are your words. I simply said it was "at the other  extreme",
meaning (although not said) at the other extreme of my  limited
experience of about 10 different models. I own only five  commercial
GPSDOs (HP Z3801A; Symmetricom Z3815A with MTI 260 OCXO; CIC  GPSR-A and
Samsung GCRU-D with Rakon CFPO-2 OCXO; and the Trimble  NTGS50AA), plus a
working relationship with the Datum and Symmetricom units  at work and a
previously owned HP Z3815A with E1938A OCXO.

I've also  built a few, but not in the class of the commercial units. My
lowest power  one is battery operated (uses a V-TCXO) and has a power
consumption of 50mW  (with display backlight off!), but is more affected
by sun load than is  desirable. Another uses the HP 10811A OCXO, and can
hardly be classed as  low power.

I have a professional interest in achieving low power in the  GPSDO, as
the company I work for are part of the Femtocell working group. I  am
certainly impressed that the Firefly is down at 1.35W.  

Murray  Greenman

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