[time-nuts] GPSDO Alternatives

EWKehren at aol.com EWKehren at aol.com
Wed Dec 5 11:28:44 UTC 2012


Chris
There is a low cost solution and I have the input circuit perfect for GPS  
on a $1 gate array I have boards and am presently using Shera original 
version.  Would like to buy his version 402NE but have not been able to get a  
response from him. Have repeatedly asked for help on this list for some one to 
 step forward to write the uproc. program. No one. The total material cost 
would  be less than $ 25 PCB included  GPS receiver OCXO or RB would be 
extra. If  the FE 5680A with RS232 would be used cost is less than $ 15. There 
are now  PIC's out there that can also do the timing function reducing cost 
even more but  that will take more smarts.
Bert Kehren
 
 
In a message dated 12/4/2012 9:06:26 P.M. Eastern Standard Time,  
albertson.chris at gmail.com writes:

With the  price of T-Bolts now higher, does it make sense to build your  own
GPSDO?

What is the simplest phase detecter that could  work?  I think only that,
and then a duouble oven crystal from eBay, a  GPS and and Arduido.

Yes the Aruino is expensive compared to a bare uP  chip but using one, I
thin you could build a GPSDO without a PCB and the  Arduino's USB connection
could be usful for power and  logging/control.

If ther phase detector where simple enough it could be  build on a prototype
board the fits on top of the Arduino.

There are  some other designs but because programming a uP and making a PCB
seem to be  rare skills that job tends to fall on one person.  Anyone can
program  an Arduino and with out need of a PCB the entire design could be
puted on a  web page and the replicated with common parts.


On Tue, Dec 4, 2012  at 4:01 PM, Bob Camp <lists at rtty.us> wrote:

>  Hi
>
> I would guess that HP/Agilent/Symmetricom and Trimble made  100X more
> GPSDO's than the next five people in the business combined  over the 1995 
to
> 2005 period.
>
> Bob
>
> On  Dec 4, 2012, at 10:26 AM, paul swed <paulswedb at gmail.com>  wrote:
>
> > Al
> > I like the truetime products. In  general easy to understand and last a
> long
> > time.
>  > But there never seemed to be that many. Sure they were used in
>  broadcasting
> > and maybe power. But the others like the 3801 and  tbolt were used in
> telco
> > and mobile apps so there were  10,000s turned out and thats why we get
> them
> > for cheap. I  simply never see the truetime dc60 or gps units around.
> Though
>  > I have my stock of dc468 sat clocks. :-) Working. I hacked a goes  sat
> > replacement 3-4 years ago.
> > That said some of the  older gps technology is a bit slippery on exactly
> how
> >  good they are.
> > So for perhaps amateur purposes they are totally  fine but when you 
start
> > comparing to a Tbolt or 3801 various  behaviors apear.
> > Odetics GPStars as an example slip cycles on  purpose. Its a mode you 
can
> > set and by default is how they are  set.
> > For what they were intended for they are perfect. But at  least 1 X10
> poorer
> > then other devices. Its not at all  broken. It was a general time piece
> for
> > radio networks.  Give or take 500 ms.
> > Regards
> > Paul
> >  WB8TSL
> >
> >
> > On Tue, Dec 4, 2012 at 9:58 AM,  Al Wolfe <alw.k9si at gmail.com> wrote:
> >
>  >>   Most of the choices I've seen here mention the Tbolts,  3801, 3805,
> etc,
> >> but I have never seen anyone mention  the TrueTime XL-AK. It advertises
> 40
> >> nsec 1 pps.  Frequency as 1 x 10-12 per day. I have one and it seems to
>  work
> >> well but have no way to test it against anything else  yet. It has four
> each
> >> 10 MHz sine output that I have  been using for house sync for HP3586,
> >> HP8924c, PTS160,  etc.
> >>
> >>   So how does the TrueTime  compare to other GPSDO's?
> >>
> >> Al, K9SI
>  >>
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-- 

Chris  Albertson
Redondo Beach,  California
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