NTP question

Brielle Bruns bruns at 2mbit.com
Wed May 1 20:01:44 UTC 2019

If you can't get a good spot for an antenna, you could be on the lookout 
for a CDMA NTP clock.


We've got one as a backup to our SyncServer S200.  Doesn't need an 
outdoor antenna as long as you can get a cellular signal in the DC.

EndRun's are Linux based and still getting software updates.  As an 
added bonus, they also do IPv6.

Of course, you're putting a lot of trust into the wireless companies 
doing this, but its a nice alternative.

On 5/1/2019 1:43 PM, Mehmet Akcin wrote:
> thank you guys, looks like GPS based NTP is the way to go.
> On Wed, May 1, 2019 at 3:36 PM Bryan Fields <Bryan at bryanfields.net 
> <mailto:Bryan at bryanfields.net>> wrote:
>     On 5/1/19 3:22 PM, Mehmet Akcin wrote:
>      > hey there Nanog,
>      >
>      > I am trying to buy a GPS based NTP server like this one
>      >
>      > https://timemachinescorp.com/product/gps-time-server-tm1000a/
>      >
>      > but I will be placing this inside a data center, do these need an
>     actual
>      > view of a sky to be able to get signal or will they work fine
>     inside a data
>      > center building?
>     You will need a clear view to the sky for at least the antenna.
>     Most GPS "antennas" are an antenna and Low Noise Amplifier (LNA)
>     which is
>     powered via 5-12v on the coax.  This sets the noise figure and gain
>     of the
>     system, so you can run 50-100' of RG6 coax if needed.  You'll need a
>     F to sma
>     adapter for this unit it looks like.  Don't worry about the impedance
>     mismatch, 50 to 75 ohm is not horrid, the RG-174 thin cable has more
>     loss in
>     10' than 100' of RG6.
>     You will not want to use the low gain puck antenna, but rather get a
>     proper
>     grounded/mounted/weatherproofed antenna such as the ubiquitous 26 dBi
>     Quadrifilar Helix antenna. https://www.ebay.com/itm/192899151132
>     -- 
>     Bryan Fields
>     727-409-1194 - Voice
>     http://bryanfields.net

Brielle Bruns
The Summit Open Source Development Group
http://www.sosdg.org    /     http://www.ahbl.org

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