Hi, this is my first post.
First off. Windows 7 USB connection to the GPS (no serial ports / modern
computer) and I'm pretty sure that is my main problem.
Past few months, I've been trying to figure out my timing issues. Lots
of reading & trying to figure out how to best configure everything. I'm
sion of precise time and frequency measurement
Subject: [time-nuts] L1 GPS timing signal(s) into local time on computer(s)
Hi, this is my first post.
First off. Windows 7 USB connection to the GPS (no serial ports / modern
computer) and I'm pretty sure that is my main problem.
Past f
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 (m
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 s
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 wrot
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 secon
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, 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 converter. It didn'
ed NTP servers? (Michael Tharp)
5. Re: Modern motherboard with RS232 port (Chris Albertson)
--
Message: 1
Date: Sun, 19 Aug 2012 10:41:39 -0400
From: Sarah White
To: time-nuts@febo.com
Subject: Re: [time-nuts] L1 GPS timing signal(
RS232 port (Stan, W1LE)
>3. Re: L1 GPS timing signal(s) into local time on computer(s)
> (KD0GLS)
>4. Embedded NTP servers? (Michael Tharp)
>5. Re: Modern motherboard with RS232 port (Chris Albertson)
>
>
> ------------------------
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
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 s
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 si
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 mail
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
On Mon, Aug 20, 2012 at 3:10 PM, Sarah White 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 back on th
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 u
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 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 bef
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 wrote:
>
>> Thanks Chris.
>>
>> I alwa
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 g
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)
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