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

Chris Albertson albertson.chris at gmail.com
Thu Oct 18 18:12:55 UTC 2012


On Wed, Oct 17, 2012 at 4:48 PM, Sarah White <kuzetsa at gmail.com> 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.

Same thing.  Lighten does not care to much about a sheet of glass,
after all it has already arced across 20,000 feet of air.  It is
really unpredictable.  Even it it hits the furnace vent on the root
your TV gets fried.  I would not worry to much unless you live in
Florida or some place like that.

Back to GPS.  The antenna a good chunk of the sky.  The GPS satellites
don't fly over the poles so there is no use looking there, nothing for
the antenna to see but if you look south the sats fly clear down tho
the horizon.  So South facing windows are better then north facing if
you have a choice.

If you are 100% indoors you don't need one of those pointy antennas
and can use a cheaper patch type.  You can duct tape it to the window

>
> 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.
>
> ... 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.
>
> (part 2)
>
> For phone chargers... Not lately, no. Both my phone, and the person
> I'm living with Have a modern phone. For the past couple years, phone
> device manufacturers give you a very tiny USB-type AC

Plug and play timing GPS system are not so cheap, even on eBay.  But
they are made by HP and others.  By plug and play I mean it comes in a
metal box with connectors for all the inputs and outputs

See eBay # 280921147498

the iLotus m12m is a great GPS and cost only $60 new but read the user
manual at this page and you see it is not "plug and play
http://www.ilotus.com.sg/m12m_timing_oncore

But yu are in luck, iLotus does sell an M12M evaluation kit that is ready to use
http://www.ilotus.com.sg/m12m_uart_evaluation_kit
but the price is higher.

The "Thunder bolt is a very populate GPS.   It is still one of the
best.  Lots of people on eBy sell them as a "kit" withj all the parts
you need. pretty much conect the wires and turn it on.
See eBay # 180446371977 the seller has already modified an old
computer notebook power supply so you don't have to find the right one
and change the connector.

About those power cubes.  If you don't have a box full of old ones,
yes you have to buy one but they cost less than $10 new.  I almost
always have to cut off the connector because it is the "wrong" type.
If you can't do that buy t "plug and play" GPS system.

I did most of the work myself, got an older UT type Oncore for $15,
had a box of power cubes and so on.  It cost less that way but I keep
an electronics bench set up with solder stationm a bunch of meters a
scope two shelves of test equipment and I studied electrical enginerin
and computer science in school (decades ago)  So for me a $60 budget
is reasonable, for you $300 to $400 is reasonable.




-- 

Chris Albertson
Redondo Beach, California



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