[time-nuts] GPSDO Alternatives

dlewis6767 dlewis6767 at austin.rr.com
Thu Dec 6 20:21:18 UTC 2012


I'm excited, for sure.

I've got a whole box of goodies over here I bought full of the Arduino uP 
and a ton of its 'shields'.  Been collecting, so-to-speak.

I just new I could use it for a, down-and-dirty GPSDO.  The Trimble Lassen 
looks good down to 20ns UTC (I got two for $10); then add a cheap datum 
ocxo; coupled that with the Arduino.  Voilà.

I can't wait, ..and you guys are reinforcing that just because its' cheap 
won't mean it won't work.

-Don






--------------------------------------------------
From: <EWKehren at aol.com>
Sent: Thursday, December 06, 2012 1:38 PM
To: <time-nuts at febo.com>
Subject: Re: [time-nuts] GPSDO Alternatives

> Paul
> I agree. That is my main frustration, lot of talk no results. The good 
> part
> of time nuts is that I have made some very good contacts that share my
> interest  of actually building some things and results are great.
> Remember the Loran simulator?
>
> Bert Kehren
>
>
> In a message dated 12/6/2012 1:17:14 P.M. Eastern Standard Time,
> paulswedb at gmail.com writes:
>
> Boy do I  have to agree. uProcs by the dozens and with all kinds of
> counters
> onboard.
> I think it was Bob who said none of thats the  challenge.
> It is the phase comparison method and a stable D/A converter and 
> reference.
> From what I have seen and I could be dead wrong here the on  board uprocs
> have D/As but the quality is simply OK.
> The other comment  is that whoever writes the software gets to choose the
> software and  everything else. Its actually not really democratic at all.
> Cause we will  all use it if its reasonably good. ;-)
> If I do it it will be basic! Though  it will run at very high speeds. Now
> someone should be jumping in with  Forth real soon now.
> Last tidbit the Rasberry is a pretty interesting  widget and there had 
> been
> a thread about a time server. Was looking forward  to the results. Nothing
> ever  happened.
> Regards
> Paul
> WB8TSL
>
> On Thu, Dec 6, 2012 at 1:00 PM,  Bob Camp <lists at rtty.us> wrote:
>
>> Hi
>>
>> It's a  rare microcontroller these days that does *not* come with a free
>>  tool
>> chain. Same goes for the debugger. Most MCU lines have family  members
> with
>> similarly low (or lower) prices and good availability.  They pretty much
> all
>> either work with a crystal two caps and a  resistor. Most will run fine
> with
>> none of the above on the internal  clock.
>>
>> Bob
>>
>> -----Original Message-----
>>  From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]  On
>> Behalf Of Dale J. Robertson
>> Sent: Thursday, December 06,  2012 12:45 PM
>> To: time-nuts at febo.com
>> Subject: Re: [time-nuts]  GPSDO Alternatives
>>
>> Arduino is Dirt Cheap!
>> At it's  cheapest it is just an atmel AVR, a crystal, 2 caps and a
> resistor
>>  with the arduino bootloader programmed into it. Easily obtainable from
>>  several sources for 5 bucks or so. All the code, toolchain etc. (the
>>  ecosystem as it were) is free. it's real easy to put one together on a
>>  piece
>>
>> of perfboard. If you're gonna put the phase detector,  dividers etc.
>> together
>>
>> anyway there's really no need  to clutter things up with some ginormous
>> commercial arduino  board.
>> Dale
>>
>> -----Original Message-----
>> From:  Keenan Tims
>> Sent: Thursday, December 06, 2012 10:38 AM
>> To:  time-nuts at febo.com
>> Subject: Re: [time-nuts] GPSDO  Alternatives
>>
>> As a lurker, I just want to chime in and say that  I for one would love
>> to see an open-source GPSDO implementation. There  are quite a few open
>> hardware designs out there, but as Bob suggests,  all the interesting
>> bits are tied up in the closed-source software  they run. And most of
>> them are no longer maintained, meaning it's  getting hard to find parts.
>>
>> I've thought on designing a  hardware platform to support a GPSDO as
>> well, but don't have the  time-nut or control theory skills (or
>> equipment) necessary to make the  software any good. My hope at the time
>> was that a build it and they  will come approach would solve those
>> problems, but I haven't had time  to make that gamble.
>>
>> As far as uP choice, Arduino's only  saving grace is the pool of existing
>> 'developers' in the amateur  community for it - but that's perhaps a big
>> deal here. It's expensive,  doesn't include debug hardware, and is slow
>> with not many peripherals.  I'd second the STM32 ARM Cortex platform, or
>> suggest MSP430 if you  want to stay cheap and slow.
>>
>> Keenan
>>  VE7XEN
>>
>> On 2012-12-06 1:28 AM, Chris Albertson wrote:
>>  > On Wed, Dec 5, 2012 at 2:50 PM, <SAIDJACK at aol.com> wrote:
>>  >>
>> >> If there is one thing I learned, it is that one is  never finished
>> >> improving
>> >>  the software.  That is why we are time-nuts I guess.
>> >>
>> > This is  the reason I suggested using the Arduino.  It is so easy to
>> >  program
>> > that MANY people will be able to contribute.  That  is my goal, a GPSDO
>> > that
>> > can be a "living project"  that is not dependent on one or a few
> experts.
>> > I'd like to see a  budget of well under $100, again so that more people
>> can
>> >  contribute and experiment.
>> >
>> > A design that can evolve  will have just about any performance people
>> want.
>> >   So don't worry about if it is 1E-12 or 1E-15.  Just make it
> transparent
>> > and easy to understand and modify.
>>  >
>>
>>
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