[time-nuts] Precision Time Protocol – Windows 10 implementation

[David J Taylor]

From: Adam Kumiszcza

Hi again!

My raspi is now in a new location. The GPS signal is fine, the window is
not south-facing, but the antenna is outside the window attached to a metal
windowsill, and there are no buildings nearby.
I'm coming back to the idea of distributing PPS signal. Do you think such a
contraption could work?
https://botland.com.pl/pl/raspberry-pi-hat-komunikacja/11707-serial-pi-plus-max3232-interfejs-rs232-dla-raspberry-pi-7426787870194.html

I mean, stacking it over the uputronics board and soldiering some pins.
The MAX3232 chip is the same as on these kind of devices:
https://www.ebay.com/itm/MAX3232-RS232-to-TTL-Serial-Port-Converter-Module-DB9-Connector-MAX232/262241627343

Cheers,
Adam
===================================

Adam,

You need to consider what cable you will use, how many devices you need to 
feed, and what distance is involved.  I've fed a couple of PCs from the same 
RS232 device, just the data out and CD (PPS) lines, of course.  Not 
paralleling the data into the GPS device.  One PC is ~4m away, and the two 
signals are fed over a twin-pair coaxial cable.  Likely a 3-core unscreened 
cable would also be OK over such a short distance.  The other PC is about a 
metre away.

If you're talking about ten PCs I would have a number of TTL to RS232 
converters, each feeding 2-3 PCs, or a controlled impedance cable (50 or 75 
ohms) with tap-offs along the cable and a termination at the far end.  The 
old thin-wire Ethernet comes to mind.

But others here have more experience than me, though, and may be able to 
recommend surplus units to do the job.

Cheers,
David
-- 
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