A while back, I decided to try putting together a small, gps local NTP
server. I have several computers on a lan and wanted to serve them all
with a locally controlled device. A bit of research (raspberry pi gps
ntp server --in my searcher) came up with several instructive
sites.Seemed easy. Is there a kit? so my current theory of buy the
biggest piece possible can be carried out? Further consult of youtube
came up with:
https://www.youtube.com/watch?v=VrDRAVy_bg4&ab_channel=JohnMiller
I saw something from John on the time-nuts forum in the past, so
contacted him re the hat he had for sale. The youtube presentation was
so clear and complete that I bought one of his hats with the
accompanying sd card. So I bought in. I put the hat on a PiB on hand,
put the antenna outside my window, and inserted the sd card as
instructed. Before the video was completely finished, the server was
running and connected to a Linux machine I had tunning nearby. As
advertised. In detail. No fuss, no muss, and it's still going strong
after two months and two power outages. WELL DONE JOHN!!!
But what about a ready to run little server? well, there are several
around. BUT, they're kinda expensive compared to the RPi setups in
various forms. I'm sort of a sucker for the cheap (er, inexpensive)
Chinese modules for various uses available on ebay or alibaba or other
sources. Apparently, a factory somewhere in Guangdong "designs" and
makes a bunch of litte modules to do something like measure voltagews,
generate frequencies, etc. These modules are then bought by the
relatives of the maker and sold on the outlets for various prices. The
problem with these modules is that there is NEVER any documentation.
You're on your own to use all your wiles, including reverse engineering,
perusal of ham radio sources, eval info from manufacturers of the ripped
chip designs, etc. Despite that, for me at least, the modules have been
cost effective. Always buy at least two.
With that in mind, I hit ebay and came up with: 363361419214 as an
example. Seemed a bit expensive, but supposed to be plug and play, wit
antenna and power. So, I ordered one up and hit the documentation trail.
Nothing! So, contacted the seller via ebay, and, after a brief hiatus
for Chinese new year, got what there is for documentaton. Mostly in
Chinese. But, I was able to find the address of the device using ANGRY
lan scanner (you do use that, no? a great piece of software!)
(192.168.0.100 btw). And that worked too. It's still working. Removing
it's pants revealed a UBLOX and a 32 bit processor, with some glue
chips. real simple.
One further note, I'm using one antenna for the two devices, courtesy of
SV1AFN (https://www.sv1afn.com/en/gnss-gps/-7.html) who makes a bunch of
good stuff.
So, it can be done. As for me, I would get the PI hat and go that way,
simply because it is not a black box, and other things are possible
using that setup. On the other hand, for less cost, the ebay module was,
once te secrets have been pried out, is totally simple to implement.
I have not tried to compare these units in any way, as there are those
of you who are far more experienced than I am. All I know is, these
approaches worked.
As usual, YMMV
73, Don
--
------------
The whole world is a straight man.:
----------------------
Dr. Don Latham AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
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