[time-nuts] Re: Current-day GPS timing receivers

[Jim Harman]

You might consider the design by Lars Walenius posted and discussed at
length here
https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/

I have built several GPSDOs based on this design, most recently
incorporating a TDC7200 TDC chip for the time to digital conversion. The
basic hardware design is very simple, but it provides good performance and
a great learning platform.

On Sat, Feb 19, 2022 at 7:10 PM Larry Gadallah <lgadallah at gmail.com> wrote:

> After poring over the several valuable references people have posted
> here, it seems that even the common commercial GPSDOs have
> implementation problems, so it seems like there's no (financially
> viable) off the shelf solution.
>
> It would indeed be convenient to have a kit option, but I'd image the
> potential marked for a GPSDO kit is vanishingly small.
>
> FWIW, I started with a VE2ZAZ board and an Isotemp OCXO and a Motorola
> receiver of questionable provenance. Since then I've gathered an HP
> 10811D and I have an HP E1938A coming (I think), so I have only so far
> gathered some essential components that I hope are competent.
>
> On Sat, 19 Feb 2022 at 07:13, Bob kb8tq <kb8tq at n1k.org> wrote:
> >
> > Hi
> >
> > Building a kit is very different than a from scratch design. A
> > Heathkit (to extend the years ago ham radio analogy) radio
> > was an option when you shopped for your Drake. Building it
> > would give you some experience.
> >
> > The Heathkit *design* was done for you and all the complicated
> > higher level stuff was worked out / tested out / reworked / retested
> > by somebody else. As long as you put it together correctly, it
> > worked and was a good radio.
> >
> > These days there aren’t a lot of folks selling kit GPSDO’s. Even
> > the kit radio business isn’t what it once was. “I’m going to do
> > a GPSDO” these days generally means a scratch design.
> >
> > Bob
> >
> > > On Feb 19, 2022, at 2:41 AM, Bill Beam <wbeam at gci.net> wrote:
> > >
> > > But there is a magazine article....
> > > <https://www.qsl.net/n9zia/wireless/QST_GPS.pdf>
> > > By Brooks Shera, W5OJM.  QST July, 1998.
> > >
> > > Following this article I built my unit in 1998 using his PCB and a
> Motorola UT+.
> > > It has been running almost continuously since then - almost 25 years.
> > > It has been thru several HP 10811 and 10844 oscillators during that
> time.
> > >
> > > Even though Brooks is SK his GPSDO is still running.
> > >
> > > Regards.
> > > Bill, NL7F
>
> --
> Larry Gadallah, lgadallah AT gmail DOT com
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-- 

--Jim Harman