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Mehmet,
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<div>I use the TimeMachines unit a lot. Usually we deploy these near any outside window, typically putting the box in the ceiling and the running the GPS antenna on its 20’ cable (or whatever it is) down to the window glass. Test different windows first before
committing. Then use any of the may passive POE injectors to inject the TM’s power brick into the Cat5 and strip it out on the other end, over a little power plug jumper that plugs into the TM box. Works a treat!<br>
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<div id="AppleMailSignature" dir="ltr"> -mel beckman</div>
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On May 1, 2019, at 12:44 PM, Mehmet Akcin <<a href="mailto:mehmet@akcin.net">mehmet@akcin.net</a>> wrote:<br>
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<div dir="ltr">thank you guys, looks like GPS based NTP is the way to go.</div>
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<div dir="ltr" class="gmail_attr">On Wed, May 1, 2019 at 3:36 PM Bryan Fields <<a href="mailto:Bryan@bryanfields.net">Bryan@bryanfields.net</a>> wrote:<br>
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On 5/1/19 3:22 PM, Mehmet Akcin wrote:<br>
> hey there Nanog,<br>
> <br>
> I am trying to buy a GPS based NTP server like this one<br>
> <br>
> <a href="https://timemachinescorp.com/product/gps-time-server-tm1000a/" rel="noreferrer" target="_blank">
https://timemachinescorp.com/product/gps-time-server-tm1000a/</a><br>
> <br>
> but I will be placing this inside a data center, do these need an actual<br>
> view of a sky to be able to get signal or will they work fine inside a data<br>
> center building? <br>
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You will need a clear view to the sky for at least the antenna.<br>
<br>
Most GPS "antennas" are an antenna and Low Noise Amplifier (LNA) which is<br>
powered via 5-12v on the coax. This sets the noise figure and gain of the<br>
system, so you can run 50-100' of RG6 coax if needed. You'll need a F to sma<br>
adapter for this unit it looks like. Don't worry about the impedance<br>
mismatch, 50 to 75 ohm is not horrid, the RG-174 thin cable has more loss in<br>
10' than 100' of RG6.<br>
<br>
You will not want to use the low gain puck antenna, but rather get a proper<br>
grounded/mounted/weatherproofed antenna such as the ubiquitous 26 dBi<br>
Quadrifilar Helix antenna. <a href="https://www.ebay.com/itm/192899151132" rel="noreferrer" target="_blank">
https://www.ebay.com/itm/192899151132</a><br>
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<br>
-- <br>
Bryan Fields<br>
<br>
727-409-1194 - Voice<br>
<a href="http://bryanfields.net" rel="noreferrer" target="_blank">http://bryanfields.net</a><br>
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