I apologize for not following the original thread closely, but has anyone
mentioned The White Rabbit Project? Here's a wiki link. Links from there to
CERN, etc. It might be beyond budget, etc.
en.wikipedia.org/wiki/The_White_Rabbit_Project
Bob
On
Hello to the list. I saw on K3PGP's site a mention that the UT-41 GPS receiver
had a 10KHz signal on-board so I decided, why not build a GPSDO for my "new" HP
5334B? Unfortunately the one I bought doesn't have a 10KHz point, and the
board doesn't even pull out the 1PPS signal from the chip. S
d.
> Be very careful with the answer. Time is the drug that keeps on giving.
> $
> Regards
> Paul
> WB8TSL
>
>
> On Thu, Jun 13, 2013 at 2:41 PM, Attila Kinali wrote:
>
>> On Wed, 12 Jun 2013 20:29:26 -0700 (PDT)
>> Bob Stewart wrote:
>>
>> > He
ge -
> From: Attila Kinali
> To: Bob Stewart ; Discussion of precise time and frequency
> measurement
> Cc:
> Sent: Thursday, June 13, 2013 3:39 PM
> Subject: Re: [time-nuts] New to list and GPSDO questions
snip
> [3] Describes how to use a clock
synchronizer to build a G
Hi Richard,
As time goes by, I'll reread your post until I understand it. I'm a newbie,
but It's hard to believe that there is enough information in a jittery 1PPS
reference pulse to be able to recover phase errors.
Bob
- Original Message -
> From: Richard H M
OK, I believe you. I can see I have a lot to learn.
Bob
- Original Message -
> From: Richard H McCorkle
> To: Bob Stewart ; Discussion of precise time and frequency
> measurement
> Cc:
> Sent: Thursday, June 13, 2013 7:04 PM
> Subject: Re: [time-nuts] Fw: New
-
> From: Chris Howard
> To: mccor...@ptialaska.net; Discussion of precise time and frequency
> measurement
> Cc: Bob Stewart
> Sent: Thursday, June 13, 2013 8:58 PM
> Subject: Re: [time-nuts] Fw: New to list and GPSDO questions
>
>
> I'm with Bob in that I don't really
Perry,
Could you give me some context for your post? Is this related to my post about
building a GPSDO, or is this something else? It looks like Bert did something
specifically for the 3586. That is not what I was posting about.
Bob
- Original Message -
> From: Perry Sandeen
> T
Tom tried to steer me to the PICTIC recently, and I sort of brushed him off,
because, quite frankly I didn't understand. Now that I've really looked at it,
it's a much better idea than using a dsPIC33 and brute-forcing it. But, I
don't really need everything the PICTIC offers so I started doin
Hi Lars,
I'm lucky in that I'm starting with a PIC running internally at 40MHz. So I
think timing is not going to be a real problem. But after getting a response
from Richard, I'm concerned about flaws in the spice chip models. I'm also a
bit concerned about breadboarding, but come to think
yet but you can contact me or Richard directly.
>
>/tvb
>
>- Original Message -
>From: "Bob Stewart"
>To: "Discussion of precise time and frequency measurement"
>Sent: Saturday, February 15, 2014 5:19 PM
>Subject: Re: [time-nuts] TIC model
>
The smart guys have already contributed to this thread. What I have is an
example taken when I was doing some testing. The plot at the top is the DAC on
my GDPSO. It is moving the oscillator back and forth about 4.6E-4 Hz. Not a
lot.
The bottom plot is the interesting one, as it is the 1P
Hi Bruce,
What are the tradeoffs with using different values for R1? I have no practical
experience at this, so all I can do is rely on the models. Does the fact that
R2 is in the PIC, and C1 is so tiny, make the value of R1 of less importance?
On my PIC, they list C1 as 5pf, R2 as effective
Now you've lost me. What 2.5 MHz synchronizer clock? Everything I have
external to the PIC is 10MHz. The PIC is running HSPLL at 40MHz, though I
don't think that makes any difference to this.
Bob
>
> From: Bruce Griffiths
>To: Bob Stew
Hi Jimmy,
Someone touched on the idea of using a scope. Go to the Agilent site and
download a copy of the 10811 manual, 10811-90002.pdf. Section 3 describes how
to adjust the 10811 and gives info on how to time the phase drift to calculate
the frequency error. You can pull the time base out
I've been experimenting with digital thermal compensation on my GPSDO. The
results have been favorable for a 14 bit dithered PWM-based DAC, but leaves a
bit to be desired in the big picture. And it takes up a lot of program bytes
on my PIC.. What's the general consensus on this? Should therm
he red (thermistor)
line.
Bob - AE6RV
>____________
> From: Attila Kinali
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
>Sent: Wednesday, February 26, 2014 10:23 AM
>Subject: Re: [time-nuts] Thermal Compensation: Digital vs Analog
>
&g
Hi Mark,
I'm neither an engineer, nor an expert, but here are my comments.
I think that the idea of 100ns/T is wrong. There are several variables that
control accuracy, but the time between pulses from your OCXO (assuming no phase
or frequency drift) isn't one of them. So, that gives 1/T.
Tom,
I took his 100ns figure to be simply the period of 10MHz. He mentioned using
an interrupt driven system, so the counts should not necessarily be limited to
100ns accuracy. At least on the PIC I'm using, the CCP and timer interrupts
don't seem to be synchronous with the PIC clock. I coul
as an interrupt function, but after
looking at the manual, it's a matter of switchable dedicated hardware. Sorry
for the bad info.
Bob
>
> From: Hal Murray
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
>Cc: hmur.
errors on your 1PPS pulse.
Bob
>
> From: Alexander Pummer
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
>Sent: Thursday, February 27, 2014 7:42 AM
>Subject: Re: [time-nuts] GPSDO with all-digital phase/time meas
Hi Charles,
The problem is that the only information available is the fact that a phase
crossing occurred and whether there were more than 10M counts (or less) since
the last PPS. The phase error value is not available to me, nor is the
sawtooth value; which would of course be of no value. So
Tom,
That's a pretty interesting idea. It makes me wonder if it would be worth it
to switch perhaps a 1/2W heat source (random number) off and on over the XO in
the UT+ say every minute or so.
Bob
>
> From: Tom Van Baak
>To: Discussion of precise time and fr
I suggested yesterday to periodically heat and cool the oscillator, but my post
may have been lost in the noise.
Bob
>
> From: Didier Juges
>To: Discussion of precise time and frequency measurement
>Sent: Tuesday, March 4, 2014 11:00 AM
>Subject: Re: [time-nu
Hi Tom,
You may have missed TVB's post yesterday, quoted below. A "hanging bridge" is
an area on a timing receiver's plotted sawtooth correction value that stays on
one side of phase zero for some period of time. As a result of this "bias", a
GPSDO that is not corrected for sawtooth will prob
I put my TIC to hardware, and have started testing it. Here is a sample run
comparing it against the 5334B with an off frequency OCXO. I've scaled and
rotated to tried to cancel out the length of the cables to the 5334B. Still
early days with it, yet.
http://www.evoria.net/AE6RV/TIC/TICvs53
nd I'm amazed at the precision of this thing.
It's like taking the 5334B and adjusting the focus knob. Of course it's not as
accurate, due to the way it works, but it will fit my needs well in my GPSDO.
Bob - AE6RV
>________
> From: Anders Wallin
The link seems garbled for some reason with it inline so let me try again.
http://www.evoria.net/AE6RV/TIC/TIC2.bmp
>
> From: Bob Stewart
>To: Discussion of precise time and frequency measurement
>Sent: Sunday, March 9, 2014 10:40 AM
>Sub
Fellow Timenuts:
I'm trying to square reality with the modeling that I did, and nothing makes
sense. When I modeled the result of just my 2.4K resistor with the caps and
resistor the PIC datasheet says it has in it, there's no relationship. The
model says
I'll get millivolts out. Here's ho
n the ADC which is listed as 120pf. Here is a screenshot
of the relevant page.
http://www.evoria.net/AE6RV/TIC/ADC.png
Bob
>
> From: Chris Albertson
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
>Sent: Monday, M
ying to be argumentative, I'm just
trying hard to understand.
http://www.evoria.net/AE6RV/TIC/ChargeRamp.png
Bob
>
> From: Bruce Griffiths
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
>Sent: Monday, March
east success is a good problem to have
and not a bad one. I'm sending a board to a friend soon, and if the results
repeat for him, it's not just a fluke.
Bob
>
> From: Bruce Griffiths
>To: Bob Stewart ; Discussion of precise time and frequ
Now that I've got the TIC going, I'm working on the PLL math for my GPSDO. My
question is about moving averages. I've put in a moving average for the TIC.
From that, I've calculated the slope, and have put a moving average on the
slope to settle it down. I think this boils down to a moving a
.com
>Sent: Wednesday, March 12, 2014 12:51 PM
>Subject: Re: [time-nuts] PLL Math Question
>
>
>Bob,
>
>On 12/03/14 18:24, Bob Stewart wrote:
>> Now that I've got the TIC going, I'm working on the PLL math
>> for my GPSDO. My question is about moving
Hi Hal,
In the moving averages I'm doing, I'm saving the last bit to be shifted out and
if it's a 1 (i.e. 0.5) I increase the result by 1.
Bob
>
> From: Hal Murray
>To: Discussion of precise time and frequency measurement
>Cc: hmur...@megapathdsl.net
>Sen
"x_avg = x_avg + (x - x_avg) * a_avg;"
Hi again Magnus,
In fact, I just post-processed some data using that formula in perl. It looks
great, and will indeed save me code and memory space. And, it can be a user
variable, rather than hard-coded. Thanks for the heads up!
Bob
>
And I suspect I'm being
far too conservative; i.e. averaging way too long If not, maybe there will be
a good gain value that will be convenient to code the exponential average.
Thanks for the help,
Bob
>________
> From: Hal Murray
>To: Bob Stewart ; Di
Hi Daniel,
re: FIR vs IIR
I'm not a DSP professional, though I do have an old Smiths, and I've read some
of it. So, could you give me some idea what the FIR vs IIR question means on a
practical level for this application? I can see that the MA is effective and
easy to code, but takes up mem
Hi Jim,
Thanks for your thoughts. Perhaps there are a few things that I know about my
particular system that have been discounted. I have mentioned them in passing,
but haven't collected them coherently for this thread. It's an 8-bit PIC, thus
floating point calculations have to be "improvis
Dennis,
I just realized that I could do the math in sixteenths. So, for 7/16ths
multiply by 7 before shifting(i.e. dividing) and rounding. That would probably
give enough granularity. I'll have to think about it. It does open new doors.
thanks,
Bob
>
>
y 256.
This has been most informative and certainly gives me more options.
Bob
>
> From: Chris Albertson
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
>Sent: Thursday, March 13, 2014 5:42 PM
>Subject: Re: [time-
I've gotten my PLL mostly working, but, since I'm using a nav receiver, it
looks like I may want to see if I can do a poor-man's sawtooth correction based
on GPS position changes. Has anyone done this or have a reference for a
project that has? It would seem to me that only the East-West movem
Hi Ignacio,
Thanks for the response. I've got a UT+ in the parts box. But that's not the
problem I'm trying to solve. I'm trying to make the best GPSDO that I can make
using a nav receiver at the moment. Call it an obsession if you like. It's OK
if I don't have corrections to the nanosecon
PS to move by that amount.
http://www.evoria.net/AE6RV/Nav/NavWander.png
Bob
>
> From: Chris Albertson
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
>Sent: Sunday, March 23, 2014 9:24 PM
>Subject: Re: [time-nuts] Nav R
I hadn't given any thought to correcting the linearity of the TIC I built, but
my PLL plots tell me I should do it now. Explanation: when I arrange things so
that the phase point is near the top of my TIC's range, it requires a smaller
movement than when the phase point is in the middle: Presu
Thanks Charles. That makes sense, but at the expense of adding unwanted
complexity. As I've been moving the setpoint around this morning, I think I
see a way to characterize what it's doing. Maybe I can come up with a small
correction table or formula that's good enough for my purposes.
Bob
de "how wide is wide". I don't have any
sort of phase wrapping code, though, so I have to be careful how close to a
phase point I get.
Bob
>____
> From: Chris Albertson
>To: Bob Stewart ; Discussion of precise time and frequency
>measuremen
Chris Albertson
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
>Sent: Wednesday, March 26, 2014 11:25 AM
>Subject: Re: [time-nuts] RC TIC linearity correction?
>
>
>
>Yes a lookup table would be easy. But how to create the table? I've bee
What about the other side of audio-phoolery: audio FFT? I'm thinking more
along the lines of an ARRL FMT.
>
> From: Tom Van Baak
>To: Discussion of precise time and frequency measurement
>Sent: Thursday, March 27, 2014 6:10 PM
>Subject: Re: [time-nuts] FEI-5
To further Brian's comment: you have to keep in mind that the interrupt routine
interrupts the mainline code, and not the other way around. So, you set a
semaphore in your mainline code and your interrupt routine checks to see if
that's set when it starts, or at least before it uses any variabl
Have you considered reading the timer only at PPS? You don't need to keep
track of the actual count. You just need to keep track of the difference
between counts at each PPS. Resolution isn't a problem since the difference in
the lower 16 bits is a fixed number for your purpose. IOW, 10,000,
My Adafruit has gone walkabout again. This is a different unit than the one I
spoke about some months ago. It's been about 150 ft from my actual location,
which has, of course, made a mess of my GPSDO. Well, at least it verified my
"unlock" code. I did a POR and it seemed to come home, but n
WAAS enabled. But I am totally clueless about
this. In 2000 words or less, what am I missing? =) Sometimes I wonder if
gpsd is meddling with things and causing me problems, in spite of their stated
goal of non-interference.
Bob
>
> From: Jim Harman
FWIW, I set the DAC to midpoint and use a binary search to get to frequency.
On my system, I start off with a change of 0x80 and work my way down to 0x04 in
powers of 2 (0x80, 0x40, 0x20, etc). Once I get to 256 seconds between DAC
changes, I light the PLL fuse. I could probably get away with
te awhile, then it drifts off, your PLL stops, and you wait till
you drift back to the phase point. Rinse, repeat, fail. But, it's always
possible that you can see something in the data that I didn't.
Bob
>
> From: Chris Albertson
>To: Bob St
idge, or that you were on a hanging bridge on one side and it's now
gone to center, a bridge on the other side, or back to a sawtooth that averages
to zero. That's probably still pretty poorly said, but it's way past my
bedtime.
Bob
>
>
bo.com
>Sent: Friday, April 11, 2014 2:49 PM
>Subject: Re: [time-nuts] Adafruit (MT3339) problems today
>
>
>On 10/04/14 23:48, Bob Stewart wrote:
>> My Adafruit has gone walkabout again. This is a different unit than the one
>> I spoke about some months ago. It
I've done as much as I can do with my little Adafruit, so I guess it's time to
move to a timing receiver. I already have a UT+, so I might as well make use
of it. My thought was to use the NTP refclock driver and probably take the
sawtooth from SHMEM with a simple "C" program to pass to my GPS
mption was that NTP would know the
secret handshake. Writing the software to extract the sawtooth is no
big deal. It has version 2.2 of the firmware.
Bob
>________
> From: Bob Camp
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
don't have the right document.
Bob
>
> From: Bob Camp
>To: Bob Stewart ; Discussion of precise time and frequency
>measurement
>Sent: Saturday, April 19, 2014 7:03 PM
>Subject: Re: [time-nuts] NTP and Oncore UT+
>
>
>Hi
>
>
Discussion of precise time and frequency measurement
>Sent: Saturday, April 19, 2014 9:36 PM
>Subject: Re: [time-nuts] NTP and Oncore UT+
>
>
>On Sat, Apr 19, 2014 at 9:18 PM, Bob Stewart wrote:
>
>> Somehow I missed that page in all the times I looked through the On
a quick
>hack GPSDO from a quality one. You'll also face a number of design issues at
>startup, and coming out of holdover. Lastly, you get to choose between it
>being an ideal time standard vs. an ideal frequency standard.
>
>/tvb
>
>p.s. Please fix your address book. Th
I mentioned to Tom that I had seen the xgps program duplicate a lot of its
satellites when I missed a PPS. I noticed my GPSDO go into holdover so I
quickly brought up xgsp and noticed it happening again. This screen showed a
few times intermixed with a normal screen. I have no idea whether it
Given the state of the GPS chip, would it really take that big an investment to
just add in the firmware to do timing? Or have the manufacturers just made a
marketing decision to keep that a high end market as long as they can?
Bob
>
> From: Bob Camp
>To: D
I was wondering if anyone has a decent interface to the Adafruit and related
receivers for Linux? By that, i mean something like the Windows tools that
Globaltop provides, or even just the ability to separate out the responses to
the PMTK commands from the NMEA traffic.
Bob - AE6RV
>_
Tom,
Any progress on the Adafruit PPS study?
(Hope this isn't a dupe. Yahoo's mail scripts have problems today.)
Bob
>
> From: Tom Van Baak
>To: Discussion of precise time and frequency measurement
>Sent: Monday, April 28, 2014 1:56 PM
>Subject: Re: [time-n
Can anyone suggest a PIC programmer that will work with Piklab on Linux? The
replacement serial board I just bought won't drive my JDM Classic PIC
programmer. It doesn't reliably drive my LIRC IR transmitter either, so I have
to devote the serial port on my motherboard to LIRC. My GPSDO devel
I neglected to mention that I'm pretty much limited to USB or ethernet (if such
a programmer exists) at this point.
Bob
From: Bob Stewart
To: Discussion of precise time and frequency measurement
Sent: Wednesday, May 14, 2014 6:15 PM
Subject: [time
Hi Rudolf,
The Pickit2 configuration choices were a bit confusing, so I decided to order a
different serial board that contains actual 16550s. Now that I've had a chance
to assimilate what I've learned, the problem is traced to the 3 Volt 3243 chips
that are in today's serial boards. After doi
Hal, you bring up an interesting point: Is the receiver in a Z3801 inherently
more accurate in position reporting than the receiver in an Adafruit? Somehow
I doubt it, if for no other reason than the improvements in technology.
(Excluding any programming errors that may or may not exist in th
Now that my TIC is working with Bert's board, I'm considering taking the next
step of designing a GPSDO from scratch. There are several projects I'd like to
do with a dsPIC33, so that was a natural choice. But I now understand that it
has an "audio" DAC and is not recommended for process contr
eresting that in one paragraph they call the DAC default register a
safety feature for industrial control applications, and then a few inches later
a black box warns that it's not recommended for control type applications.
Bob
____
From: Poul-Henning Kamp
To:
have some of the same issues. Even some pretty fancy
outboard ADC’s only work well at DC if you put a chopper around them.
Bob
On Jun 2, 2014, at 7:22 PM, Bob Stewart wrote:
> Hi Poul,
>
> I've been reviewing microchips literature and the way I read it is that the
> DAC isn&
There was a recent discussion with the above subject line about SVN-64. I've
noticed that my Adafruit hasn't given me any holdovers for a few days, so I
checked on the sat's status. The link below says it's been usable since May30.
Hmmm.
http://www.navcen.uscg.gov/?Do=gpsShowNanu&num=2014047
Once I got my TIC going, I suppose it was inevitable that I build a GPSDO with
a dsPIC33. I have a few dsPIC specific questions for anyone who designs with
them.
1. VCAP. The datasheet says that it should be a surface mount device. I had
hoped to avoid those. Can I get away with a 10uf tant
In an offline communication, I suddenly realized that I hadn't given any
thought to the user interface for my GPSDO. Is there an accepted standard
interface for GPSDOs, or is that a murky Microsoft-esque world of patents and
lawyers?
Bob - AE6RV
___
this important issue until now.
Bob
________
From: bownes
To: Bob Stewart ; Discussion of precise time and frequency
measurement
Sent: Wednesday, June 25, 2014 7:35 PM
Subject: Re: [time-nuts] GPSDO standard interface?
Well, I built one of the ve2zaz units, and
prototype GPSDO right now that requires all sorts of
user input just to get it started and to keep it going. That gets old. My bias
is: time spent creating clever adaptive algorithms to make a human unnecessary
is better than time spent creating an elaborate UI that requires a user (and
operation
Hi Mark,
Thanks for the response. I'll take a look at heathgps.cpp. I had hoped not to
have to actually look through code to divine an interface, but if that's the
way it is, then OK. I am planning on the output of at least position,
corrected phase error, DAC value, ambient temperature, and
Perhaps the misunderstanding happened when I mentioned two UARTs and two tty
interfaces. Using a standard tty interface has nothing to do with how it gets
to the monitor hardware once it leaves the board. It's the same physical
interface that's used by the receiver boards; whether Adafruit, U
You might be thinking of the file that David Byrne sent to the HP list last
year on 9/7/13. It was an article by C. L. Stong and I think it was published
in The Amateur Scientist in 1963. You should be able to find it in the HP list
archives.
Bob
From: M
There's an interesting (and on topic) project in that book starting on page
335, discussing a home-made Magnetic Resonance Spectrometer. I wonder if any
time-nuts have constructed such a device, and what potential accuracy it would
have?
Bob - AE6RV
From: D
Jim,
Are you trying to find out how to hook up a receiver in your office/radio room
to an antenna that is some ways away? Or are you specifically trying to
remotely hook up a receiver near your antenna? If the former, just use RG-6,
like for cable TV, with adapters on each end. RG-6 has such
as close as possible to
a system which which would have the systems gpio and serial ports attached?
Thanks to you both for answering.
jim
On 7/1/2014 9:30 PM, Bob Stewart wrote:
> Jim,
>
> Are you trying to find out how to hook up a receiver in your
> office/radio room to an anten
First, an apology. When I changed the topic on my original post, I thought
that would be OK. Apparently that's still a thread-jacking. Sorry.
I'm still interested in this Magnetic Resonance Spectrometer thing, though. On
page 335 of the pdf linked below by Dave, there's an experiment with an
Thanks Brooke. I'll look into it. It would be interesting to try to develop a
frequency standard from a test tube of water.
Bob
From: Brooke Clarke
To: Bob Stewart ; Discussion of precise time and frequency
measurement
Sent: Sunday, July 6, 20
I'm a bit confused about what you're asking. You discuss antennas but you show
pictures of a GPS receiver. They're not the same thing. I use a puck antenna.
They cost about $6 on ebay, and take their power from the coax. Normally your
GPS receiver supplies power to the coax, so you don't ha
Have you looked into NTP for Windows?
Bob
From: Max Robinson
To: Time Nuts
Sent: Saturday, July 12, 2014 6:29 PM
Subject: [time-nuts] Setting Windows XP clock.
As some of you no doubt know microshaft has stopped supporting windows XP.
As part of this the
I got one of these recently, along with the adapter board. This is the ublox
only version, and I am using u-center version 8.11 software. I am unable to
make it work properly. The NMEA section happily sends out messages, but I
cannot get anything else to work. e.g. it ignores the commands to
o had experienced
problems.
Bob
From: Art Sepin
To: Bob Stewart ; Discussion of precise time and frequency
measurement
Sent: Tuesday, July 15, 2014 5:58 PM
Subject: RE: [time-nuts] Synergy-GPS SSR-6tru problems
Bob,
One of the most obvious things is that the UT+ u
ant good answers I think you need to tell us exactly what you are
plugging it into and through what signal path you are issuing the commands.
On 7/15/2014 2:36 PM, Bob Stewart wrote:
> I got one of these recently, along with the adapter board. This is the ublox
> only version, and I am using u
wasted
all this time for nothing.
Bob
From: Dennis Ferguson
To: Discussion of precise time and frequency measurement
Cc: Bob Stewart
Sent: Tuesday, July 15, 2014 11:46 PM
Subject: Re: [time-nuts] Synergy-GPS SSR-6tru problems
On 15 Jul, 2014, at 16:32 , Bob Stewart wrote:
> I do n
I'll have to look at the specs to see current
draw.
Bob
From: Paul
To: Discussion of precise time and frequency measurement
Sent: Wednesday, July 16, 2014 2:33 PM
Subject: Re: [time-nuts] Synergy-GPS SSR-6tru problems
On Wed, Jul 16, 2014 at 2:
As a reminder, I received an SSR-6tru receiver from Synergy, along with their
M12 adapter, which allows you to plug it into a slot for an Oncore GT+, UT+, or
VP. I was unable to get the receiver to respond to any commands from the
u-blox u-center software.
After a lot of troubleshooting, I dis
There was a discussion recently about how to send the 1PPS from a receiver to a
remote user. If this is duplicate information I apologize.
Get a copy of the Motorola Oncore manuals and take a look at Chapter 5 where it
discusses using RS-422 to do this. Simple schematics and timing informatio
EXE s/w today.
/tvb
- Original Message -
From: "Bob Stewart"
To: "Bob Stewart" ; "Discussion of precise time and frequency
measurement"
Sent: Wednesday, July 23, 2014 3:19 PM
Subject: Re: [time-nuts] Synergy-GPS SSR-6tru Problem Resolved
As a reminder, I
e was talking about. A
real class act all around!
Bob - AE6RV
From: Art Sepin
To: Bob Stewart ; Discussion of precise time and frequency
measurement
Cc: Tom Van Baak ; Dusty Morris
Sent: Friday, July 25, 2014 5:17 PM
Subject: RE: [time-nuts] Synergy-GP
I've run into a noise problem on the EFC line of my GPSDO engine at the
frequency of the oscillator. I've traced the source down to the 74HCT365 I'm
using to output the 1(or 5)MHz and 10MHz signals. When I pull it, the EFC
quietens down a lot. I'm seeing about 50mv of 10MHz noise at the outpu
e OCXO on my old Tek 455 with an
X10 probe.
Bob
________
From: Bob Stewart
To: Time Nuts
Sent: Tuesday, August 5, 2014 1:36 PM
Subject: [time-nuts] Effects of noise on EFC line?
I've run into a noise problem on the EFC line of my GPSDO engine at the
frequ
What about a PC sound card?
From: Alexander Pummer
To: Discussion of precise time and frequency measurement
Sent: Thursday, August 7, 2014 5:06 PM
Subject: Re: [time-nuts] Low noise powersupplies
to measure a power supply noise, better to say the noise spe
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