[time-nuts] Oncore VP problem
GandalfG8 at aol.com
GandalfG8 at aol.com
Wed Jul 18 19:24:06 EDT 2007
In a message dated 18/07/2007 21:25:35 GMT Daylight Time,
jason at extremeoverclocking.com writes:
I wouldn't worry too much about not having TRAIM. As long as your GPS has a
good view of the sky you should be alright. If you really need a higher-end
receiver then there's the newer M12M-T.
Do you have any pictures of the adapter board / product? I'm curious to see
what it looks like.
----------------
Hi Jason
I don't really need anything any better right now, just being greedy:-)
Although it would have been nice to have the extra timing options I'm just
pleased to find I have the PPS output after all.
With most of my test gear in storage right now, including Z3801A and other
references, I was looking for a quick way to check out a Parthus GPS standard
that hasn't been behaving quite as I expected.
The QEX project from last year seemed to offer an ideal solution, without
the output dividers/drivers it's just one PIC, one op amp, and a level
shifter.....
if you don't count the GPS receiver and an HP 10811 that is:-)
The unit I'm using was marketed around 1996 by Maplin Electronics in the UK
as their "GPS Development System".
I bought this one recently from a company who had it as left over NOS, they
used them in 1997 as accurate timing sources for lighting/effects in a theme
park.
Maplin are quite a large retail chain in the UK, similar to RadioShack but
without the radios:-), and they also published a magazine at the time.
I think this may have started as a magazine project that they decided to
market as a finished product.
Basically, it's just an Oncore on an interface board that contains a MAX232
IC and a 5 volt regulator.
I suspect it's very similar to the Motorola evaluation kit.
It's put together quite nicely in a small extruded case but doesn't seem to
be very well designed.
To start with, they rate the supply from 8 to 16 volts with a 16 volt
electrolytic across it.
Probably ok, but I prefer a margin so changed it.
The electrolytic across the negative 8.5 volt output from the MAX232 was the
wrong way round, I thought it was a one off until I found the PCB marked up
that way.
And finally, as I mentioned earlier, the front panel screening is wrong.
Other than that, it seems ok:-)
I've got a photo of the outside but that doesn't tell you much so I'll take
some pictures of the PCB etc and let you have those later.
I'll also try to provide a copy of the interface schematic.
regards
Nigel
GM8PZR
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