[time-nuts] Meinberg or T/Bolt for PC time?

Hal Murray hmurray at megapathdsl.net
Mon Aug 11 17:09:43 EDT 2014

chris at chriswilson.tv said:
> I have 4 windows based PC's on my home network, for years i have used
> Meinberg or an equivalent to set the PC time. I was wondering if I could, or
> should, use my permanently on Trimble Thunderbolt to set the PC clocks? Any
> advantages or disadvantages. I believe there's a way to use Lady Heather to
> interface with a PC for setting the time, is that true? Thanks. My main
> desire for accuracy is amateur radio digital modes. 

What sort of accuracy do you want/need?  How good is your current network 

Is there a good web page describing amateur digital modes and/or the timing 
accuracy they need?


albertson.chris at gmail.com said:
> Pick one of the PCs, the one you are going to leave running 24x7 and connect
> that one to theTB using a serial cable.  Yes a real RS232 serial cable.   It
> is MUCH better to use a serial port then a serial to USB dingle.     When
> you guid the serial cable make sure the PPS from the TB is on the DCD line
> and get the polarity correct. 

The TBolt doesn't come with the PPS on the DB-9 connector.  If you pull the 
cover off, it's easy to add a jumper from the BNC connector to the unused DCD 
pin on the DB-9.

That may not work well.  The problem is that the PPS pulse is short.  
Sometimes it works, sometimes it doesn't.  If it works when you test things, 
it may fade out when you turn around.  Depends on your PC and whatever.  YMMV 

You can add a FatPPS from TAPR.

I kludged in a diode, R and C.  (The R limits the charging current.  It 
discharges through the RS-232 receiver.)  It works.

These are my opinions.  I hate spam.

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