If you're interested, I have a page that shows what all the M12 test points
are. I used those, not the connector. Used to be on the Synergy site,
along with lots of other info on the M12.
Bob
-----Original Message-----
From: paul swed
Sent: Friday, February 18, 2011 11:58 AM
To: beale ; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] advice: frequency calibration to 1 ppm possible
without GPSDO?
As a heads up. I picked up a M12+ from fluke.I. Working well. But the little
pins are a sun of a gun to work with. They are really small. So you may need
to order a connector and pins. Since that would cost more then the M12 I
soldered directly to the pins and added some leads.Now I can use any
connector or none at all.
Regards
Paul
WB8TSL
On Fri, Feb 18, 2011 at 2:51 PM, beale <[email protected]> wrote:
Hi Kasper,
Thank you, your nft program looks very interesting! It turns out the local
ISP that provides my DSL, sonic.net runs a GPS-driven NTP server and I
have a pretty low and stable latency, so this may work well. To measure a
relative frequency offset, I presume that what limits accuracy is the
total
length of time of the test. So with a stable latency, I should not need to
poll the server very often.
Meanwhile I have a M12+ timing GPS and antenna on order, and am assembling
some glue logic, case, 3.0V power supply etc. I may not ever manage a
long-term GPS installation, since my apartment is surrounded by tall
obstructions, and my workplace has metallized-film window panes which
block
all GPS signals, and no roof access. It has a big open parking lot,
though... I imagine using a car-mount GPS setup and sending a 1 Hz or 100
Hz
LED or laser pulse up through the window to a telescope / photodetector at
my workbench on the 2nd floor.... or maybe sending a frequency-locked 10
kHz
tone through a FM wireless mic system would be adequate.
-John Beale
> I did a piece of software to provide calibration to equipment-deficient
microcontroller-hobbyist frequency counter builders (think 100ppm crystal
from the bin) over ntp:
> http://n1.taur.dk/nft/nft.pdf
> /Kasper Pedersen
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