Hi Dana,
The antennas were in the window, top of the lower pane of a two pane window.
Certainly a better location that the antenna sitting on the desk.
There were several other units that showed similar behaviors. I suppose it’s
possible that there was interference. There were 7 antennas in 3
Denny,
That is certainly a large difference. But I'm not clear on one point that
could
easily be very important:
Were the two antennas for the separate antenna test indoors, or on the roof?
If indoor, I kind of suspect that the difference might mostly be attributed
to the
change in antenna
I don’t seem to be able to attach the pics to the emails correctly to allow the
mailing list software to process them. Rather than bombard everyone with any
more attempts, I put them up on Dropbox.
You can find the pics here:
https://www.dropbox.com/sh/fbbfuydqac5qqql/AAADkwrcVL8u5nkHvi8ecMe3a
[Resend—hopefully pics come through this time]
One additional interesting thing which I didn’t anticipate is the effect of
moving from multiple (puck) antennas to a single antenna.
The graph below shows the relationship between two LeoNTP units in the local
network as perceived by chrony. The
[Resend—hopefully pics come through this time]
Thanks Bob, this is in fact what I ended up doing. I bought a pair of the L1 /
L2 / L5 antennas from China, one for rooftop mounting at the new site, and one
for testing. I paired it with a splitter from GPS Networking. 35 feet of RG-213
from the
Long-term there is no drift to measure between regions. With each region on
its own GPS receivers and atomic clocks, it seems much more likely that
anything you measure will be asymmetries in network delays between regions.
Note that like Google has since 2008, AWS "Time Sync" also smears out
Note that AWS uses something they call smearing for leap seconds. Before you
use that service, make sure this is something you want.
-Original Message-
From: time-nuts On Behalf Of Vlad
Sent: Monday, April 29, 2019 11:14 AM
To: Discussion of precise time and frequency measurement
Hi
Looks like that should work. Don’t forget about grounding / lightning
protection …
Bob
> On Apr 29, 2019, at 2:21 PM, Denny Page wrote:
>
> Thanks Bob, this is in fact what I ended up doing. I bought a pair of the L1
> / L2 / L5 antennas from China, one for rooftop mounting at the new
Folks,
I'm awaiting delivery of a Quartzlock A7 (older version, pre-A model, or
A7-MX). I found a reference from Riley to a link to the spec sheet which has
since been removed from Quartzlock's site. I have a decent idea of operation
from reading the A7-A manual, but I suspect there are some
Thanks Bob, this is in fact what I ended up doing. I bought a pair of the L1 /
L2 / L5 antennas from China, one for rooftop mounting at the new site, and one
for testing. I paired it with a splitter from GPS Networking. 35 feet of RG-213
from the antenna to the splitter, and 3 feet of rg-58
One additional interesting thing which I didn’t anticipate is the effect of
moving from multiple (puck) antennas to a single antenna.
The graph below shows the relationship between two LeoNTP units in the local
network as perceived by chrony. The system clock is synced to the first LeoNTP
Hello Folks !
Some time ago Amazon AWS has introduced "Time Sync Service"
https://aws.amazon.com/about-aws/whats-new/2017/11/introducing-the-amazon-time-sync-service/
Looks like it is just some NTPD (based on chrony). I am wandering how to
measure drift between of AWS regions (internal
I'd been to Greenwich more than once, but it was Dava Sobell's book,
Longitude, that allowed me to understand their importance and seek them
out.
On Mon, Apr 29, 2019 at 1:00 PM Jim Palfreyman wrote:
> Thanks Brooke.
>
> I remember walking into the Greenwich Museum for the first time, NOT
>
Thanks Brooke.
I remember walking into the Greenwich Museum for the first time, NOT
KNOWING that Harrison's clocks were in there. And ticking away.
Just amazing.
Jim
On Mon, 29 Apr 2019 at 13:00, Brooke Clarke wrote:
> Hi:
>
> Video of working Harrison clocks.
> https://youtu.be/T-g27KS0yiY
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