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Date: Fri, 23 Sep 2011 14:10:43 +0200
From: Jan Ceuleers <jan.ceuleers@gmail.com>
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To: Dave Taht <dave.taht@gmail.com>
Subject: Re: Preliminary results of using GPS to look for clock skew
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Cc: "Eric S. Raymond" <esr@thyrsus.com>, bloat-devel@lists.bufferbloat.net
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On 09/23/2011 11:38 AM, Dave Taht wrote:
> Thirdly - as much as I would like to get a PPS signal, that seems
> impossible with the hardware we are
> currently playing with. That said, delays/variations of 10ms are not a
> real problem as the bufferbloat signal
> can often be measured in close order of seconds.
>
The cheapest GPS timing receiver, which includes a PPS signal, that I am 
aware of is the Garmin GPS18LVC. It requires soldering to a serial port 
connector, and also needs a +5VDC power source such as can be obtained 
from a USB port, but it is a very capable device.

Note that it needs to be the LVC variant - other variants of the GPS18 
lack the PPS signal.