On 8/21/12 9:53 AM, Sarah White wrote:
Wow. Okay. The user manual actual considers this cable delay to be worth
mention?
I can see why the trimble thunderbolt is a favorite among time nuts 3
I'm sold.
Cable time offset is in basically all GPSes. An awful lot of GPS
receivers (for timing)
On Mon, Aug 20, 2012 at 3:10 PM, Sarah White kuze...@gmail.com wrote:
I really like that the thunderbolt can (assuming the initial location
has been uploaded, or the default site survey has been completed)
still keep accurate time / discipline based on a single satellite lock
(before falling
Thanks Chris.
I always appreciate clear explanations. I'm assuming that the fixed
location requirement is important to note for purposes of compensating
for any dopler shift, as well as the distance the signal must first
travel before being decoded.
... I would presume that the fixed location
On 08/21/2012 12:35 PM, Sarah White wrote:
Thanks Chris.
I always appreciate clear explanations. I'm assuming that the fixed
location requirement is important to note for purposes of compensating
for any dopler shift, as well as the distance the signal must first
travel before being decoded.
On Tue, Aug 21, 2012 at 9:35 AM, Sarah White kuze...@gmail.com wrote:
Thanks Chris.
I always appreciate clear explanations. I'm assuming that the fixed
location requirement is important to note for purposes of compensating
for any dopler shift, as well as the distance the signal must first
Wow. Okay. The user manual actual considers this cable delay to be worth
mention?
I can see why the trimble thunderbolt is a favorite among time nuts 3
I'm sold.
On 8/21/2012 12:48 PM, Chris Albertson wrote:
On Tue, Aug 21, 2012 at 9:35 AM, Sarah White kuze...@gmail.com wrote:
Thanks Chris.
kuze...@gmail.com said:
... I would presume that the fixed location used for above calculations
would be relative to the position of the antenna?
A side effect of figuring out where you are is figuring out when you are
there.
There are 4 unknowns: X, Y, Z, T, so you need 4 equations. You
On Sun, 19 Aug 2012 15:29:22 -0400, Sarah White wrote:
oh wow, thanks. I'll try that.
Also, I figured out that typing in trimble thunderbolt instead of
thunderbolt gps gives me zero hits for phone... but fewer hits for the
GPSDO too :(
Try to search on : 10mhz gps
You should see most
CFO:
oooh, really.
So 10mhz reference is pretty standard for a GPS disciplined frequency
standard. Thanks.
I really like that the thunderbolt can (assuming the initial location
has been uploaded, or the default site survey has been completed)
still keep accurate time / discipline based on a
kuze...@gmail.com said:
... Is that a common feature? Know of any good ones other than the trible
thunderbolt?
It's standard in GPSDOs. It requires special firmware in the GPS unit.
--
These are my opinions. I hate spam.
___
time-nuts
Just order one from RJB1998
(http://www.ebay.com/itm/120969870669?ssPageName=STRK:MEWNX:IT_trksid=p3984.m1497.l2649)
Friday and it's here today. $169 with free shipping. He included a power
cable (6 pin to leads) and a TNC-F cable.
Mike Blazer
On 8/20/2012 4:07 PM, cfo wrote:
On Sun, 19 Aug
kuze...@gmail.com said:
this is a no-name cheapo SIRF module
1) I need a computer with a serial port. The curent GPS module I'm using is
INTERNALLY RS232 -- USB converter, and recognized by my windows 7 computer
as: Prolific USB-to-Serial Comm Port (COM3) ... the latency and jitter is
I will jump in a bit. I, and many have been right where you are. You are
correct...USB is a no go for accurate time. Same on windows. So you need a
Linux box with serial port. Anything from a Beaglebone, pandabox...or pc will
work. You certainly need a gps with a pulse per second output
Just one further question.
When the pps input triggers, so my linux box knows a second has just
ticked; is the time of that second the one the NMEA sentence has just
sent, or will send next?
Or to put it another way, when I receive an NMEA sentence is this the
current time (as was when the
The time when the names sentence was sent is the time in the sentence.. The pps
signals every second..they are independent. Tat is the very nature of the
problem with the nmea sentence..latency associated with the message itself.
Sent from my iPad
On Aug 19, 2012, at 6:11 AM, Ken Duffill
Ken:
From what I've read, most GPS modules which output PPS, the NMEA
sentence has the timestamp of the next, upcoming pulse. Regardless of
how the NMEA or other time data is, the PPS itself is only a guarantee
this is the boundary for a second and NTP documentation typically
recommends a second
In my experience (which is admittedly less than that of many others here) the
time reported is that of the PPS pulse that just happened, and the
documentation usually bears that out. There's a real-time clock running inside
the receiver that is synchronized to the PPS. At the top of the second,
On Sat, Aug 18, 2012 at 10:23 PM, li...@lazygranch.com wrote:
If you are using a desktop, I'd suggest putting in a serial card. The
Netmos chip based cards work on windows and linux, though your should do an
internet search on the particular card before you buy.
I have the prolific based
measurement
time-nuts@febo.com
Subject: Re: [time-nuts] L1 GPS timing signal(s) into local time on
computer(s)
Message-ID: ae1d2790-af2b-40fc-88d8-f13a61d77...@mninter.net
Content-Type: text/plain; charset=us-ascii
In my experience (which is admittedly less than that of many
)
--
Message: 1
Date: Sun, 19 Aug 2012 10:41:39 -0400
From: Sarah White kuze...@gmail.com
To: time-nuts@febo.com
Subject: Re: [time-nuts] L1 GPS timing signal(s) into local time on
computer(s)
Message-ID
Another option is a low end laptop.
I use a Dell D400 laptop, with a 1.8GHz Pentium M and it draws about 20W from
A/C with the display blanked, which is the way an NTP server will be most of
the time.
The power brick rating assumes running the laptop AND charging the battery at
the same time.
If you are using a desktop, I'd suggest putting in a serial card. The Netmos
chip based cards work on windows and linux, though your should do an internet
search on the particular card before you buy.
I have the prolific based converter. It didn't work with my Starloc. (The
netmos worked fine
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