245-9115
>
> -Original Message-
> From: time-nuts On Behalf Of Bob kb8tq
> Sent: Wednesday, October 7, 2020 7:34 PM
> To: Discussion of precise time and frequency measurement
>
> Cc: hmur...@megapathdsl.net
> Subject: Re: [time-nuts] Aging 5065A ?
>
> Hi
Hi
Well….. the existing synth in the 5065 is no champion spur wise. Coming up with
a
DDS that is “as good as” is not all that crazy.
The 5 MHz reference is multiplied to 6.x GHz and then mixed with the synth. The
close in
phase noise of the multiplied signal is mixed with the synth. The output
th of the accumulator. What about the D/A
> then? 73 - Mike
>
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell NJ 07731
> 848-245-9115
>
> -Original Message-
> From: time-nuts On Behalf Of Bob kb8tq
> Sent: Wednesday, October 7, 2020 1:55 PM
> To: Discussion
Hi
> On Oct 7, 2020, at 4:25 PM, John Ackermann N8UR wrote:
>
> Hi Attila --
>
> Just a couple of corrections -- the "coarse clock" in the TICC runs at 10 kHz
> (100 us), not 1 kHz, and therefore the TDC never sees a measurement interval
> longer than 100 us, not 1 ms.
>
> More importantly,
S
> 89 Arnold Blvd.
> Howell NJ 07731
> 848-245-9115
>
> -Original Message-
> From: time-nuts On Behalf Of Bob kb8tq
> Sent: Wednesday, October 7, 2020 11:11 AM
> To: Discussion of precise time and frequency measurement
>
> Subject: Re: [time-nuts] Aging 5065A
n the A7 opamp so a lot of good work.
>>> But the charcoal problem mentions really would be the worst problem to
>> deal
>>> with. I guess it would be ebay parts. $$$ Whats a dead 5065 go for
>> chuckle?
>>> Regards
>>> Paul
>>> WB8TSL
>>
Hi
> On Oct 7, 2020, at 10:34 AM, Ulf Kylenfall via time-nuts
> wrote:
>
> Regarding the quest to keep a 5065A running...
>
>
> The 5065 in my hobby corner was equipped with the firstversion of the
> AC-Amplifier (A7) that did not have a frequency
> selective 2nd harmonic detector. So I c
parts. $$$ Whats a dead 5065 go for chuckle?
> Regards
> Paul
> WB8TSL
>
> On Tue, Oct 6, 2020 at 6:27 PM Bob kb8tq wrote:
>
>> Hi
>>
>> Replacing the synthesizer with something more modern is certainly
>> possible. I have
>> a project (slowly mov
ng in. The same for the synthesiser. I could
> swear someone on time-nuts already has. The phase detection circuit is
> audio and it would take some experimentation. I think Corby supplied an
> alternative approach on the A7 opamp so a lot of good work.
> But the charcoal problem ment
Hi
Replacing the synthesizer with something more modern is certainly possible. I
have
a project (slowly moving along) to do just that. There is nothing crazy on the
logic board,
it could easily be replaced with something more modern for not a lot of money.
The phase detector / photo amp / modul
Hi
You *are* talking about a 60 KHz sine wave when playing with WWVB. The
typical receiver had a fairly narrow passband. This generally was accomplished
with both high Q tuned circuits and a crystal filter. The typical antenna loop
antenna
also had a fairly high Q tune on it. Even if the signal w
Hi
The height of the ionosphere changes night to day. That changes the effective
propagation distance. As the day/night (or night/day) transition point crosses
the
path between you and WWVB the two “modes” compete with each other. They
can do fun stuff like cancel out the signal entirely.
If yo
; Thanks,
>
> Bill
>
> .ılılı..ılılı.
> notfaded1
>
> On Sun, Oct 4, 2020, 2:54 PM paul swed wrote:
>
>> Agree with Bobs comment. The 180 degree phase flip killed all of the gear
>> unless significant mods are done or the d-psk-r is used. Great old boxes
>>
Hi
This is another of the many devices out there that pre-date the
“modern” 180 degree phase modulation approach on WWVB. Getting
one of these to run properly with the new modulation approach would take
some major mods …..
Bob
> On Oct 4, 2020, at 10:23 AM, Magnus Danielson wrote:
>
> Hi,
>
Hi
On an oscillator that is 50 years old, there likely has been some aging of the
crystal
and other components. As you tune the crystal back onto frequency, you can
easily
impact the EFC sensitivity. On *any* older device, “measure” is very much the
right
way to do it.
Bob
> On Oct 2, 2020,
s again.
> Kind Regards
> Joe
>
>
> On Thu, Oct 1, 2020 at 5:58 PM Bob kb8tq wrote:
>
>> Hi
>>
>>> ……..
>>> So, I am a little lost in understanding how to characterise this animal,
>>> and how to measure what. I
Hi
> ……..
> So, I am a little lost in understanding how to characterise this animal,
> and how to measure what. I get the feel its performance is actually very
> good, but I don't know why, nor how to defend that statement.
>
> HELP!!
>
> …...
Unfortunately the only accurate way to characteriz
Hi
The 53131 RS232 thinks it is talking to a printer. You need to enable that on
the sub menu *and*
then restart ( = power cycle ) the counter. Once it is turned on, you can muck
with the serial parameters
to get them to line up with your needs.
Bob
> On Sep 30, 2020, at 5:39 PM, cdel...@juno.
Hi
> On Sep 30, 2020, at 11:45 AM, Luiz Alberto Saba wrote:
>
>
>
> Em 29/09/2020 14:08, Bob kb8tq escreveu:
>> Hi
>>
>> You have a lot of stuff that runs off of GPS L1. Any “common mode” issues
>> (like ionospheric disturbances) will propagate into a
Hi
> On Sep 29, 2020, at 10:23 PM, Dana Whitlow wrote:
>
> Mark:
>
> I don't have a PPS syncable PRS-10 yet, but will probably be getting one
> within a
> year or so. My expectations are not great, however, because I already know
> that
> the received GPS time has diurnal wiggles to the tune o
Hi
The gotcha with *any* SMT part is that stress / strain from the soldering
process gets into the
performance of the part for a *long* time. There is no mechanical “buffering”
in most parts. Whatever
the PCB does is what the guts of the part sees ….
Given the popularity here on the list of h
Hi
You have a lot of stuff that runs off of GPS L1. Any “common mode” issues
(like ionospheric disturbances) will propagate into all of them. What impact
that
has on each one is very much a “that depends” sort of thing. The firmware and
filtering quickly get into the act …. They all will wander,
Hi
Trace around the input filter. There are coils there that may
go open. There are also a couple of board mount fuses that
pop from time to time.
Bob
> On Sep 29, 2020, at 8:07 AM, Tim Tuck wrote:
>
> And as soon as I posted this I found what I was looking for on KO4BB's
> website - I forg
Hi
Indeed the most stable (long term) standard is a very high end RTD. These
devices have a lot of voodoo
in their design. Even with all that, they still arrive with a note on the box
that reads “ for applications requiring
< 10 mk, re-calibrate before use”. More or less, you *also* need a trip
ack to the well?
>
> David
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob
> kb8tq
> Sent: 28 September 2020 14:23
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Symmetricom XPRO rub
Hi
Depending on your setup, a very normal passive power splitter could do the
job quite well. The 8 port Mini Circuits versions show up on eBay for $20 to
$30
(delivered).
Bob
> On Sep 28, 2020, at 4:25 AM, Kevin Rowett wrote:
>
> I’m in need of a GPS distribution amp. Looking at choices a
Hi
> On Sep 27, 2020, at 10:19 PM, Stewart Cobb wrote:
>
> I have a Symmetricom* XPRO rubidium which appears to be reaching its end of
> life. The very sparse manual says that it sets a "service" flag when the
> lamp voltage reaches 600 mV. When I got it, that parameter was at about
> 540. Sever
Hi
You would need to find a temperature sensor rather than a voltage reference…. :)
The AD590 still seems to be considered a pretty good device after all these
years. If there is long
term data in the spec sheet, I did not spot it in a quick read. Based on what
we saw back in the 1970’s
(which
Hi
> On Sep 27, 2020, at 11:59 AM, Jeremy Nichols wrote:
>
>>
>>
>>
>>> We used three thermistors and averaged them.
>>
>> I assume they were spread around in case one side of the package was
>> warmer than the other.
>>
>
>> Could one do an analog “average” by using a set of, for example
s/thermistor-info/thermistor-terminology/stability.aspx
>>
>> <https://www.littelfuse.com/technical-resources/technical-centers/temperature-sensors/thermistor-info/thermistor-terminology/stability.aspx>
>>
>>
>>
>> Bruce
>>
>>> On 27 September
Hi
> On Sep 26, 2020, at 7:22 PM, Magnus Danielson wrote:
>
> Hi John,
>
> On 2020-09-26 17:10, John Ackermann N8UR wrote:
>> We know that phase noise scales with frequency, so if you multiply
>> frequency by 10 you get a 20 dB increase in noise.
>>
>> What I don't fully understand is how th
Hi
Roughly speaking 99.9% of all OCXO’s use thermistors as temperature
sensors.
The normal evaluation process on a new one *probably* would catch something <
0.01C
over a few months. You may do it a couple different ways depending on the target
OCXO. The net result is still in the “golly ge
Hi
In addition, the input to the ADC has it’s own noise issues. If you have a
really
clean clock (or a poor ADC), the noise floor of the input may dominate the
noise floor.
Bob
> On Sep 26, 2020, at 12:28 PM, jimlux wrote:
>
> On 9/26/20 8:10 AM, John Ackermann N8UR wrote:
>> We know that p
Hi
One interesting “oops” using RTD’s:
They are close cousins of strain gauges. Some RTD designs are *very* close.
Mount them to this or that and they may tell you more about the stress / strain
in the mount than about the temperature.
You do *not* want to know how many (hundred) temperature te
Hi
Going back a bit to get closer to the original request …..
Indeed a thermistor is the “high resolution” king of the hill when it comes to
temperature
measurement. Resistance change of 3% (30,000 ppm) per degree is not uncommon,
you can do better …
They come in all sorts of packages for not a
Hi
Two basic types of SLA / VRLA batteries out there: AGM and Gel. For the AGM
variety, you want a bit more to your charger. I haven’t worked with Gel cells
in
a while so they may indeed be easier.
Bob
> On Sep 25, 2020, at 4:17 PM, Poul-Henning Kamp wrote:
>
> --------
> Bob
Hi
Properly charging batteries is a bit complicated. Why does “properly” matter?
You want them to be fully
charged, but not damage them in the process. That generally involves some sort
of variable voltage
for the charging source. If you decide to go with Lithium based parts, you can
get BMS (b
Hi
If you run a straight linear regulator setup, then you *do* indeed have a
battery voltage
that is (nominally) much higher than the “target” voltage. If you run a diode
voting input,
then the “normal” voltage will be even higher. You can easily get into the 35
to 40V range
doing this.
Bob
Hi
> On Sep 25, 2020, at 5:44 AM, Hal Murray wrote:
>
>
>> 1) In an unconditioned/semi-conditioned space. The ambient temperature can
>> slew 20*C easily over the holdover period. (Think sun hitting an outdoor
>> enclosure first thing in the morning - the ambient temperature tends to rise
Hi
How often do you loose power? If it’s once a year for < 1 hour …. how big an
issue is this to you? Do you *need* to do precision measurements every day?
Is restarting a run once a year a major issue? Option one is to simply restart
after an outage. Option two is to protect against it.
To pro
Hi
Maximize life = put it on the shelf and *never* power it up. It (may) last for
a century that way.
How you will *know* it’s still doing fine is very unclear.
Maximize utility = power it up and keep it on power all the time. If you can
plan well, power it
up 9 months before you need to use
Hi
> On Sep 23, 2020, at 8:20 PM, Forrest Christian (List Account)
> wrote:
>
> I'm hoping some of the list are familiar with the newer currently-available
> oscillators available from the distributors.
>
> Some background:
>
> I'm starting to play with a short-term 1PPS holdover application,
Hi
> On Sep 24, 2020, at 6:32 AM, Hal Murray wrote:
>
>
>> I'm starting to play with a short-term 1PPS holdover application, mainly to
>> cover up brief GPS signal loss events (a few minutes at most).
>
>> I'm probably looking for an OCXO instead of a TCXO, although it looks like
>> some of
Hi
An alternative:
Take the pps out of a ( or maybe several) GPS modules.
Divide your oscillator to (about) 1 pps.
Feed them into a counter(s) of some sort (TICC or 53xxx or whatever …)
Log the data to a file with any serial program you might pick.
=
At this point you have a data file(s
Hi
Most OCXO’s similar to the 8600 series use a glass bead thermistor up around
100K ohms. The range of betas available is pretty limited up there. They likely
used two in an attempt to reduce the impact of forced cooling to one side vs
another.
Bob
> On Sep 20, 2020, at 8:59 AM, ew via time-
Hi
> On Sep 14, 2020, at 3:59 AM, Matthias Welwarsky
> wrote:
>
> On Sonntag, 13. September 2020 15:05:36 CEST Bob kb8tq wrote:
>> Hi
>>
>> The point is that there is no need to compensate the part while it is
>> locked.
>
> It depends. For sho
Hi
As mentioned in PHK’s post, FPGA’s are quite noisy. They also tend to have
crosstalk issues if you put a whole bunch of nearly identical inputs into them.
So backing off a bit:
What are you trying to measure? Are you after parts in 10^-13 or parts in
10^-8?
That will make a *big* differenc
Hi
Ok so you have a step change in temperature of say 2C over 5 seconds. What
(might) happen:
(Yes this is all a bit contrived, but it *is* the sort of thing that’s going on
in the TBolt). The units
shown are “Bob Units” :). They have no particular relation to LSB’s or to
PPT’s.
At 18 second
playing with
compensation. It met the
spec so why spend the money …..
Bob
> On Sep 13, 2020, at 10:28 AM, Adrian Godwin wrote:
>
> But doesn't the compensation help generate a feed-forward term, a way to
> make the integrator better managed ?
>
> On Sun, Sep 13, 2020 at 2
* learn at the same time generates even
more issues to deal with. The temperature effect is not a simple linear / first
order sort of thing ….
Bob
> On Sep 13, 2020, at 1:41 AM, Matthias Welwarsky
> wrote:
>
> On Samstag, 12. September 2020 23:53:39 CEST Bob kb8tq wrote:
>> H
ned part 48050-61 but as you say, that seems to be common to all of
> them.
>
>
> On Sat, Sep 12, 2020 at 10:14 PM Bob kb8tq wrote:
>
>> Hi
>>
>> The unit your link points to *is* the “classic” TBolt that showed up in
>> volume a bit
>> over a decade ago
Hi
As far as anybody knows (which *is* a big qualifier indeed ….), the TBolt
family only
does it’s “temperature compensation” stuff when it’s in holdover. While it’s
locked, there
*appears* to be no compensation being done. If it’s doing anything while
locked, it’s
learning what the TC is, so
Hi
The unit your link points to *is* the “classic” TBolt that showed up in volume
a bit
over a decade ago. That one is packaged with a (noisy) switching power supply.
There is no easy way to tell what era it is from. Indeed if it is from the
1990’s the
OCXO will not be quite as good as what’s
> On Sat, Sep 12, 2020 at 2:17 PM Bob kb8tq wrote:
>
>> Hi
>>
>> One *might* consider reaching out to those winding down Spectrum and see
>> if they might be willing to “donate” the source code to IEEE ( or some
>> similar
>> institution ). That’s what was d
Hi
One *might* consider reaching out to those winding down Spectrum and see
if they might be willing to “donate” the source code to IEEE ( or some similar
institution ). That’s what was done with Stable-32.
Bob
> On Sep 12, 2020, at 1:04 AM, Lloyd Blythen wrote:
>
> Thanks Bob.
>
> About a m
nk&utm_campaign=sig-email&utm_content=webmail>
> Virus-free.
> www.avast.com
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> On Fri, Sep
Hi
If it was a custom chip, then the motor driver “stuff” would be integrated into
the
IC. That was indeed the case back in the 1970’s when I was designing this sort
of thing. Those chips were pretty hard to dig up, even back then. Unless you
wanted
to buy >10K pcs a month, they really didn’t w
Hi
Well …. 4.19304 = 2^22
I’d bet they used a bunch of divide by 2 ( or 2^N ) parts. :)
At some point they went from electronic division to driving gears. Is that what
he’s looking for?
or is he after the brand / model of divider chip? It’s quite possible that they
used a custom part,
even ba
Hi
A couple things to check:
1) Is your power supply doing odd things? It’s the first thing I’d suspect in
this case.
2) Does the OCXO “behave” if you turn off the GPS ( = disconnect the antenna )
and watch
it with a counter?
3) While the antenna is disconnected from the TBolt, hook it to so
Hi
Unless the pad is damaged, it makes a fine “gap filler” to attach the device
to a heatsink. You don’t get thermal compound all over everything when using
the pads ….
Given the (large) surface area and the amount of heat involved, the relative
performance of silver loaded (gray) thermal compou
Hi
Maybe a good idea to “back up” a bit here:
The most commonly plotted data for the performance of a GPSDO is ADEV.
Very simply put, to do ADEV you take a series of readings at a specific time
spacing ( called tau ). The delta frequency from one reading to the next is then
computed. You take t
Hi
Depending on your definition of “accuracy”, and the actual device, the answer
is likely
in the 1 ppb to 10 ppt range based on a 10 second measurement.
What’s going on?
First up you have the basic accuracy of GPS. Over many days of averaging (with
a fairly
fancy averaging device) that can b
t but my notes confirm I was way off). I do hope to move up to a
>>>> basic
>>>> home lab running off CSAC and Rb standards in the next few years once
>>>> I've
>>>> seen all there is to see in wristwatches, but it looks like I have a
>&
like I would need to set up GPIB.
GPIB is great for setting up multiple runs on a counter or for doing odd things.
One of those is running 100 second long data with a 5335. There are cheap
USB dongles out there to do the GPIB if you decide to go that way.
Bob
>
> On Tue, Sep 8, 2020, 1:12
Hi
First off, 0.001 seconds per year is ~ 3x10^-11. If you are talking about
the 2G tip effect on a typical AT cut crystal that’s up around 2 ppb.
Next up, low frequency / small package crystals are (inevitably) relatively
low Q devices. Low Q degrades ADEV performance / increases noise. If
you
gt; ref: https://ww1.microchip.com/downloads/en/DeviceDoc/22003e.pdf
>
>> Sent: Monday, September 07, 2020 at 1:15 PM
>> From: "Bob kb8tq"
>> To: "Discussion of precise time and frequency measurement"
>>
>> Subject: Re: [time-nuts] 5 Digit Pane
Hi
You actually have at least three components to your setup:
1) You have the *source* impedance of your signal
2) You have the impedance / length / loss / stability of the cable connecting
the
source to the load
3) You have the load impedance.
In an ideal world, you would have cable that i
Hi
So, *assuming* there is no other ADC on the board ….
DC performance of the STM8 ADC’s is somewhere in the 8 to 9 bit range as far
as ENOB with significant averaging. For the sake of simplicity, let’s say they
*do*
make it to 10 bits.
But … do we get the 10 bits?
The range on the meter is 3
Hi
Measurement accuracy as stated in the listing is 0.3% or 3,000 ppm. Some
listings call it out
as 0.3% +/- 2 LSD. Since they removed the markings from some of the chips,
figuring out exactly
what’s in there could be a bit exciting.
Full scale is 33V so the full range display would be 33.0
Hi
The gotcha with all this is the temperature coefficient. If they all have
roughly the same +100 ppm / C tempco (which they might), then the typical
lab temperature swing of 2 to 4 C will have them out in the 200 to 400 ppm
range (and more or less tracking each other ….).
1 LSB on a 16 bit pa
Hi
A number of us have Trimble TBolt’s that have been running for over 10 years.
The early HP’s (Z3801 … ) seem to have a weakness in the power supply section.
So far mine have come back to life after simple repairs. That puts the into the
20+
year range. The “Nortel” GPSDO’s seem to just keep
Hi
> On Sep 4, 2020, at 3:37 PM, Matthias Welwarsky wrote:
>
> Dan,
>
> I've attached the last 25000 seconds of data. The drift was about 15 DAC
> units
> during this time. It's a 16 bit DAC, the pulling range is about 10Hz, so LSB
> is worth 1.5e-4 Hz. 15 DAC units are 2.3e-3 Hz over 2500
Hi
….. ummm …. e …..
> On Sep 4, 2020, at 2:04 PM, rfnuts wrote:
>
> Hi,
>
> given it is a 10MHz OCXO, your drift is just 4E-11/hour or 9.6E-10/day, which
> isn't terribly bad, is it?
>
> A good modern OCXO is specified at +/- 0.2ppb/day (2E-10) after 30 days of
> continuous operation.
Hi
Best guess is that the oven circuit has “issues”. If that’s the case, it will
go on pretty much forever and ever. Without a plot, it’s sort of hard to
guess ….
Bob
> On Sep 4, 2020, at 2:50 AM, Matthias Welwarsky wrote:
>
> Hi,
>
> I mentioned in a previous email that I seem to have pick
Hi
OCXO aging is not “linear” in the fashion you are trying to interpret it. Put
another way,
daily aging does not equal yearly aging / 365. Hourly aging does not equal
daily aging / 24.
The drivers are not that simple or that well behaved. If you find a spec that
calls out a lot
of details, t
Hi
That interface board *may* use a biased transistor to convert sine to square.
It’s been a while since I looked at it …..
Bob
> On Sep 2, 2020, at 10:00 AM, Mike Feher wrote:
>
> I remember the days when we had to build our own discrete Schmitt trigger to
> do this. 73 - Mike
>
> Mike B. F
Hi
> On Sep 2, 2020, at 1:24 AM, Manfred Bartz wrote:
>
> Hi all,
>
> I bought 2 x 10811 OCXOs for a 10MHz GPSDO project I am working on.
> The OCXOs came with an interface board HP 05328-20027, see attached
> pictures.
>
> Questions:
> 1. Is it worth keeping the interface board?
They make an
Hi
The one thing you don’t want to do is play with insulation. There are two ovens
in a
normal Rb. Their temperatures are close to each other. It will not work if the
temperatures
are equal ( = there are reasons for the delta).
Since the two ovens are right up against each other, there is non
ating heating is often
>> conducted to keep it hot inside. How do I reconciliate these opposing
>> conditions in actual use?
>>
>> ---
>> (Mr.) Taka Kamiya
>> KB4EMF / ex JF2DKG
>>
>>
>>On Tuesday, September 1, 2020, 2:08:04 PM EDT, B
Hi
> On Sep 1, 2020, at 4:09 PM, Hal Murray wrote:
>
>
> kb...@n1k.org said:
>> I believe that they simply don’t have a body of long term data “in house” to
>> study.
>
> Interesting topic.
>
> How many units do you have to test to get useful data?
Likely a couple hundred spaced out over a
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
> On Tuesday, September 1, 2020, 2:08:04 PM EDT, Bob kb8tq
> wrote:
>
> Hi
>
> In this case there may not be much that can be done. In the more general case
> ( = a unit with a surface that mates to a
Hi
In this case there may not be much that can be done. In the more general case
( = a unit with a surface that mates to a heatsink) , it’s well worth doing
something.
I have an unfortunate lot of empirical evidence (on FRK’s and LPRO’s ) showing
that
a “no heatsink” setup is one with a short
Hi
Since you don’t know all the parameters of the design of the 53310, it’s going
to be
tough to define “best” in terms of an OCXO. None of the parts on your list are
better
than a 10811 in all respects.
Best to simply get a couple of 10811’s for $40 or so and spend some time
sorting them
out
Hi
> On Aug 28, 2020, at 7:11 PM, Scott Armstrong wrote:
>
> Hi all,
>
> I have a Matsushita CCA532ST02 GPS antenna that has been sitting in a parts
> box in the garage probably for the past 20 years.
> I've done a few searches on the web for specs but have come up empty. I
> believe this GPS a
Hi
> On Aug 27, 2020, at 10:35 AM, Poul-Henning Kamp wrote:
>
> --------
> Bob kb8tq writes:
>
>> Common wisdom is that there is a filter in the cavity match that
>> is specific to 60 MHz. Putting in 120 MHz apparently does not work
>> well. I haven’t tried it
Hi
Unless you are going to dig in and rebuild the microwave part of the physics
package,
you are limited in terms of what you can or can’t do. The SRD setup seems to be
a bit
unique in the 5065 so messing with it probably isn’t a good idea.
Common wisdom is that there is a filter in the cavity
Hi
Normally the parts I am looking at are the run of the mill eBay parts.
They are < 10 years old, but have been on boards. It is rare that they
will not tune to frequency (if they have output ….). My guess is that the
typical modern OCXO is good for 20+ years before they age out of spec.
Bob
>
Hi
Regardless of who made it, OCXO’s often don’t do well after being knocked
around.
The process of puling them off pcb’s is stressful to the internals. The shock
and vibration
in normal “junk box” storage can be an issue. As a result, the original
performance data
may not be of much use.
I’
Hi
Keep in mind that a GPS receiver is *very* sensitive to close in phase noise on
the clock source.
If you dig into the data sheets on the chip sets, they are quite explicit about
this. Any approach you
use to steer the TCXO will need to be very quiet.
Next, the internal firmware *assumes* th
Hi
> On Aug 13, 2020, at 6:35 PM, ed breya wrote:
>
> I have often wondered about all this sawtooth correction stuff, and I think
> I've asked here too, but never got a definitive answer. Every time this comes
> up, there are all sorts of explanations of the characteristic, and inevitably
> s
id
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob
> kb8tq
> Sent: 13 August 2020 14:39
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] ! PPS Source
>
> Hi
>
> Here’s t
Hi
Here’s the “whole story”, sorry if it repeats things you already know …
All GPS modules that I have ever seen use a free running clock. The internal
oscillator is *not* locked to GPS. When they want to generate a 1 pps output
they drop / add cycles from the the internal oscillator to get it “
Hi
Oscillatek was acquired by K&L in the early 1980’s. K&L was acquired by Dover
in
the mid 1980’s. Dover acquired Vectron Labs in the early 1990’s. All data on
the
Oscillatek parts is long gone …. even to the person who ran the company ( = me
) ….
Simple answer:
Hook up a power supply an
ston many
> nights.
> Enjoying the thread.
> Regards
> Paul.
>
> On Tue, Aug 11, 2020 at 7:45 PM John Magliacane via time-nuts <
> time-nuts@lists.febo.com> wrote:
>
>> On Tuesday, August 11, 2020, 07:14:12 PM EDT, Bob kb8tq
>> wrote:
>>
>>&
Hi
The problem with the crystal is that it has a temperature coefficient. As a
narrow band filter, it will have a *lot* of delay. Crystal resonance moves
(with temperature) and the delay changes.
How much delay depends a lot on a bunch of fiddly details. A 10 to 100 Hz wide
bandpass could easi
Hi
As long as you sample “fast enough”, you can recover phase. Indeed, even if
you sub-sample (sample to slow), you can still get phase back with a few
relatively minor constraints. Since one of those is “don’t sub sample at exactly
a fraction of the carrier”, a sub-sample “locked” receiver would
chieved by just listening into what's
> > already transmitted (like GPS) and do some math on our side.
> >
> > On more broader sense, was GPS originally designed to provide timing
> > service? Or is it a byproduct of needing to measure location and speed,
>
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
> On Sunday, August 9, 2020, 9:21:23 PM EDT, Bob kb8tq
> wrote:
>
> Hi
>
>
>
>> On Aug 9, 2020, at 7:03 PM, Tom Van Baak wrote:
>>
>> Hi Stu,
>>
>> There's no problem
Hi
> On Aug 9, 2020, at 7:03 PM, Tom Van Baak wrote:
>
> Hi Stu,
>
> There's no problem with a semi-commercial posting here. You've been a member
> for a decade and frequent contributor plus the subject matter is exactly
> on-topic. So thanks for posting.
>
> I spent a while on your web si
Hi
The main point is: If you are looking at a VLF system, phase matters a lot. If
your
objective is a 100 ns @ 1 second sort of accuracy, you need a very stable phase.
At 100 KHz, you are looking at 3.6 degrees of phase shift. Go down to 60 KHz and
you are right at 2 degrees. Head to Omega sort o
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