[ntp:questions] Re: Refclocks for the Ultra-Cheap
Richard B. Gilbert
rgilbert88 at comcast.net
Fri May 6 23:08:05 UTC 2005
>What are some extremely cheap options for locally attached
>refclocks, preferably under $400 total cost? I don't need
>extreme accuracy. Frankly accuracy to one second is sufficient.
>The application is Kerberos. For various reasons the networks
>internal time server cannot easily use an NTP client, so I really
>prefer to find a locally attached refclock.
You can purchase a Motorla M12+T GPS timing reciever with "hockey puck"
antenna and evaualation circuit board for around $200 US. This should
work fairly well if you can site the antenna where it will have an
unobstructed view of the sky. See:
For more money, I don't know exactly how much, you can get the Motorola
timing receiver combined with an antenna in a small plastic "radome"
which will deliver a serial output to your computer via RS232 or RS422
(supports up to 500 meters of cable)
See http://www.synergy-gps.com/GSynQ_EnTN-813.pdf for specs on this one.
You can find a lot of equipment on e-Bay. Depending on where you are
located, it may be possible for you to use a receiver for an HF or VLF
time signal WWV, WWVH, or WWVB in the US, CHU in Canada, etc. The
vagaries of radio propagation tend to make this a poor second choice for
me but your mileage may vary.
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