[time-nuts] Followup (still want a GPS-type NTP refclock)

Jim Lux jimlux at earthlink.net
Thu Oct 18 00:26:35 UTC 2012


On 10/17/12 4:48 PM, Sarah White wrote:
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> On 10/17/2012 6:04 PM, Chris Albertson wrote:
> ((...snip...)) -- 1
>> Indoor antennas can work.  It depands on the details.  Hopefully
>> the skylight looks to the south.  BTW that thin sheet of plastic
>> that makes the skylight window will not protect from lightening.
>> It makes little difference.
> ((...snip...)) -- 2
>> It means those "plug-in" power suply boxes that plug into a wall
>> outlet and have a coaxial power plug.  They are use to power cell
>> phone charges and notebook computers and you name it.   Most
>> people have many of those around the hose.  The output voltage will
>> be printed in the cube
>
> (part 1)
>
> This is a glass skylight window, not plastic.
>
> Also, the skylight window in question is not the highest point on the
> roof, there is a domed metal cover on an exhaust fan vent thingy...
> Regardless though, landlord won't allow things to go on roof or in the
> yard so I'm stuck with using the window.


Skylights work fairly well.. just stick the antenna on the bottom of the 
window and hope for the best.  If you have a handheld GPS (or phone 
which does GPS), you can hold it up there and see if it works.

The worst case is that they've put some sort of metallic film on the 
window to reduce thermal losses.. There are ways to fix that, but 
non-trivial.



>
> ... Basically, this way I won't have to consider any waterproofing for
> the antenna, and just hope that if lightning strikes it goes for the
> exhaust vent dome thingy instead... Ah well whatever. My plan remains
> unchanged in this regard --- it is going to be in one of the
> south-facing (roof is angled) skylight windows.
>
>
> And that's with a $6 navigation GPS thingy (USB puck-type NMEA-only)
>
> That's navigation... Timing mode only needs "1 satellite lock" after
> all, and I suspect I will at minimum be able to get needed "1
> satellite lock" with nearly any active GPS antenna.
>


Ah, but this is Time-Nuts.. are you sure you don't need 1E-13 
performance?  You may not think you do today, but inevitably, the 
horrible uncertainty in your time stamps will gnaw at your innermost 
soul, and pretty soon, you'll be building choke rings, wrapping your $6 
receiver in an oven, cobbling together some weird combination of surplus 
parts.



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