[time-nuts] TCVCXO Adjustment

Bob kb8tq kb8tq at n1k.org
Sat Apr 14 09:00:41 EDT 2018


Hi

The uBlox based parts will provide pretty good timing into a directly connected 
PC. By that I mean, they are on a dedicated USB controller hooked directly to
the CPU. 

In this context, the objective is microsecond level timing. We’re not after 
a TimeNut couple of nanoseconds. Even if it’s 10 us, you still get to 0.1 ppm 
in 100 seconds…..

Bob

> On Apr 14, 2018, at 12:59 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
> 
> 
> kb8tq at n1k.org said:
>> The alternative is to plug a USB GPS into the mac and do a bit of code to
>> compare things. If you want to pass the gizmo around to your friends …. that
>> can be done. Pretty good ones are “sub $10” delivered.  
> 
> USB GPS gizmos generally don't have a PPS and the timing on the NMEA 
> sentences is generally crappy.  (I may be biased by a few bad examples.)
> 
> Does anybody have a list of ones known to work well?
> 
> There is at least one GPS-USB with PPS, the Navisys GR-601W/GR-701W/GR-801W,  
> They were hard to get retail.  Looks like idealez sells them Taiwan for $47 
> for the 701W (Ublox 7), $50 for the 801W (Ublox 8) (plus shipping).  I 
> haven't tried ordering through them.  Gary and/or Mark may have some for sale.
> 
> ----------
> 
> Plan B is a GPS breakout and a USB-serial breakout and a few wires.  4x less 
> USB jitter if your USB-Serial chip is full-speed.
> 
> I got mine from SparkFun:
> Venus GPS with SMA Connector
>  https://www.sparkfun.com/products/11058
> USB to Serial Breakout - FT232RL
>  https://www.sparkfun.com/products/12731
> 
> ----------
> 
> Google found this.  I don't know anything more:
>  https://www.zti-communications.com/z050-gps-dongle/
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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