age (5.05V nominal)
> INA219 OCXO Current (2A maximum)
> TIC (10-bit, 1024ns max)
>
> When a value is not available, the field contains "0".
>
>
>
>
>
> On Fri, Apr 1, 2022 at 2:43 PM Bob kb8tq wrote:
>
>> Hi
>>
>> The drift used in th
Hi
Well, specific to Old Faithful ….
They look at the current eruption and rate it for height and duration.
Based on that rating, they make a guess about the wait for the next
one. Their guess is typically a +/- 10 minute sort of thing. Very much
like predicting the weather.
Hi
Given the (very normal) lack of information on the crystal,
it becomes a “try it and see” sort of thing. They seem to
want 12.5 pf as the load cap for the first one listed on the
data sheet. How far off of that is your circuit as it sits?
First step would be to take the “output” cap up one
standards used in national time scales ….. ( and why having them all one
model from one company wasn’t a great idea ).
Bob
> On Mar 31, 2022, at 10:06 PM, Chris Caudle <6807.ch...@pop.powweb.com> wrote:
>
> On Thu, March 31, 2022 6:28 pm, Bob kb8tq wrote:
>> Consider the ca
should take that
> rubidium oscillator to a
> calibration vendor and pay them to test it, correct?
>
> Then, we can measure?
>
> Neal
>
>
> On Thu, Mar 31, 2022 at 4:43 PM Bob kb8tq wrote:
>
>> Hi
>>
>> Consider the case:
>>
>> GPS shifts (
Hi
If you are trying to evaluate things like accuracy and stability,
you really can’t do it internally. You need something else to
compare to. If you want to count number of dac bits of change
per hour, you certainly can measure that. Just what it means ….
Bob
> On Mar 31, 2022, at 7:15 PM,
in the three GPSDOs under test?
>
> On Fri, Apr 1, 2022 at 12:02 AM Bob kb8tq wrote:
>
>> Hi
>>
>> The gotcha of looking at one GPSDO against another is that
>> the GPS side of things is “common mode” to all of the devices.
>>
>> Bob
>>
>>>
eporting, and then collect the data from the 4 different GPSDOs
> I have here (3 x STM32 GPSDO + 1 x Lars' DIY GPSDO), and then setup
> the Three-Cornered Hat measurement apparatus, and then collect more data,
> etc...
> Oh the joys of time-nuttery!
>
> On Thu, Mar 31, 2022 at 9:0
Hi
One word of caution:
You really can’t compute things like ADEV by observing the device against
itself. You need an external / stable reference that is (hopefully) much more
accurate than the GPSDO to compare it to.
Bob
> On Mar 31, 2022, at 2:18 PM, André Balsa wrote:
>
> Hello
Hi
> On Mar 26, 2022, at 6:37 PM, Richard (Rick) Karlquist
> wrote:
>
>
>
> On 3/25/2022 12:41 PM, John Ackermann N8UR wrote:
>> PS -- an interesting feature of these oscillators is that they are an "S12"
>> variant that has a little accelerometer bolted on and hooked to the EFC
>> circuit
Hi
Even in a commercial environment where one would *think* that
all the issues had been spotted and worked out long ago, issues
like this pop up pretty often. Any time you take this sort of data,
you very much need to look at what’s going on and see if it makes
sense.
If there was a “one
Hi
To convert 1.2 uV / sqrt(Hz) to something else, first you would need to know
the target bandwidth. On a TCXO Vtune it could be almost anything. Just to
get started, let’s make a random guess of 2.5 KHz. Sqrt(4K) gives us 50 which
is the main reason for picking that number.
50 x 1.2 = 60 uV
or conversion.
>>> Did stick the antenna out of the window for a clearer view of the sky and
>>> picked up 8-10 db. The house blocks to the north.
>>> Regards
>>> Paul
>>> WB8TSL
>>>
>>> On Mon, Mar 21, 2022 at 5:50 PM Bob kb8tq wrote:
>&
ney on bench gear :) :) :). In terms of
this
project, what you have sounds like it’s doing the job just fine.
Bob
>
> On 5-3-2022 20:50, Bob kb8tq wrote:
>> Hi
>>
>> One suggestion on the frequency plot:
>>
>> TimeLab as you have it set does a “per pixe
Hi
More NetRS trivia:
One of the features of the NetRS is that it will act as an NTP server.
It’s not the most modern device so I very much would not want to
serve a ton of clients off of one. It also has been a *long* time since
the OS was patched. If you are looking for “modern” features or
Hi
The simple answer is to not log the data to the card at all. Just
grab it “real time” via the serial port or the ethernet port. Both
ports can be set up to “send when ready” so there is no need
to do a bunch of polling to grab the information. Since you
have multiple serial connectors and
ue, it should then be possible to adapt the loop time constant, until
> some sort of optimum is found. No?
>
> Best
> Tobias
> HB9FSX
>
>
> On Sun., 20 Mar. 2022, 20:03 Bob kb8tq, <mailto:kb...@n1k.org>> wrote:
> Hi
>
> If you want “best” jitter compared to the
Hi
If you want “best” jitter compared to the GPS PPS, put in a very wide
band loop and move the OCXO very quickly to match the PPS. That
will give you best performance by that measure. If you go to every
tenth sample, the same process will occur, just at a slightly different
point.
Since the
; To be useful for time nuts I believe I really do need a dual band L1/L2
> antenna.
> Regards
> Paul
> WB8TSL
>
> On Sun, Mar 20, 2022 at 11:06 AM Bob kb8tq <mailto:kb...@n1k.org>> wrote:
> Hi
>
> A bit of NetRS flash card trivia:
>
> The origina
oting up the system does blink the lEDs but not the gps satellite or
> Frequency LED. The frequency LED will be easy to check.
> Regards
> Paul
>
> On Sat, Mar 19, 2022 at 4:55 PM Bob kb8tq <mailto:kb...@n1k.org>> wrote:
> Hi
>
> Quick way to take apart a Ne
Not a real problem
> but is easy to get mis-aligned.
> When booting up the system does blink the lEDs but not the gps satellite or
> Frequency LED. The frequency LED will be easy to check.
> Regards
> Paul
>
> On Sat, Mar 19, 2022 at 4:55 PM Bob kb8tq <mailto:kb...@n1k.org&
Hi
Quick way to take apart a NetRS:
1) Pull out all the screws from the front panel ( the one with the LED’s on it).
2) Pull the screws from the mounting bracket (if it’s still there). All are T10
Torx.
3) Reverse the Torx driver and use it as a small hammer. Tap the “ears” on
the front
Il giorno dom 6 mar 2022 alle ore 23:48 Krishna Makhija <
>>>>>> km...@virginia.edu>
>>>>>> ha scritto:
>>>>>>
>>>>>>> Hello Tom,
>>>>>>>
>>>>>>> Yes, the
Hi
The PPS out of a “normal” GPS module is derived from a free running
TCXO. The edge it puts out is only approximately correct. The magic
term for this a “sawtooth” since the departure from correct phase can
look a bit like a sawtooth when you plot it.
Many modules provide a “sawtooth
Hi
I swap out the CF cards on the NetRS pretty much as soon as they show
up. I had three of them die and that convinced me that waiting was not an
option. I’ve never had an issue with any of the connectors breaking in the
process. I’m by no means some sort of super tech ……
Bob
> On Mar 13,
Hi
New flash card on the NetRS:
1) Pop off the front cover, flip the latch on the flash holder and pull the
old card. Carefully put it somewhere safe :)
2) If you can find a 512 Mb flash card, good for you. At least around
here 1 GB is an easier thing to dig up. Download the image that will
Hi
Finding *anything* in stock these days can be exciting.
There do seem to be uBlox M8T based boards in stock. An F9T board would be more
fun, but
does not seem to be very easy to find. They do have F9T modules in stock. That
would mean
doing up some sort of PCB to mount it on.
Bob
> On
Hi
As everybody runs off to scoop up the NetRS gizmos on eBay:
Like a lot of gear, they have a flash memory card in them. That card is
(fortunately) removable. Some of the cards are well past their likely end
of life point. Just as with other devices, working out which card makes
them happy can
Hi
> On Mar 9, 2022, at 5:00 PM, Hal Murray wrote:
>
>
> kb...@n1k.org said:
>> If your drone is moving at 15 KPH, that???s a bit over 4 m/s. Roughly
>> speaking, you would need updates at > 10 per second to keep this from
>> dominating the result. This would be true of both survey and
gt;> error between two discrete oscillators. However, I am hoping to use
>> the
>>>> PPS
>>>>> and FEE metadata to compute what the phase *should* have been in
>>>>> post-processing. So far, it is not working out for me. I am wondering
>>> if
Hi
Adding insulation to an Rb is a very tricky thing. There are
two heated zones. They need to both be at the correct
temperature. If the “cold one” gets to hot, things stop working.
No, this isn’t the root cause issue here. If you bulb does not light
then that’s the root cause. Bulbs do go
HI
> On Mar 8, 2022, at 2:31 AM, ed breya wrote:
>
> Just an interesting observation. Last night, shortly after I wrote about my
> dual GPSDO system, I decided to take a look at it, with the usual scope setup
> looking at both 10 MHz outputs. It looked like one of those reasonably good
>
Hi
The Mosaic T dev board is the same as the normal Mosaic dev board
except they populate it with a T module and likely make some other
minor “stuffing” changes as well.
The gotcha is that you can quickly and easily order the normal dev board
online. For whatever reason that’s not true of the
>> 10
>>> ns is >360 deg. With a common-mode reference I see a small phase change
>> (+-
>>> 3-4 deg) but that is not an option for my application.
>>>
>>> Where does the PPS offset come from? Isn't it from the positioning error?
>>> Typic
ight be
> able to order by talking to them directly and paying using a credit card.
>
> On Sun, Mar 6, 2022 at 1:51 PM Bob kb8tq wrote:
>
>> Hi
>>
>> How close are you trying to get?
>>
>> How far apart are the GPSDO’s?
>>
>> A “run of th
gt; At first impression the phase noise is not terrible, now the calibration
> needs to be done by comparing with a 10MHz source with known (bad) phase
> noise.
> The audio analysis SW used can do dB/log Hz.
> Will be interesting to share the results here and hear your feedback.
> Erik.
>
Hi
How close are you trying to get?
How far apart are the GPSDO’s?
A “run of the mill” number would be out around 100 ns. A “pretty good”
number is in the 20 ns range. A “crazy good” number would be 2 ns. To
do better than this, you likely would need to go to a more exotic configuration
on
noise measurement?
> Erik.
>
> On 5-3-2022 20:50, Bob kb8tq wrote:
>> Hi
>>
>> One suggestion on the frequency plot:
>>
>> TimeLab as you have it set does a “per pixel” process on its charts. You have
>> a limited screen resolution and a ton of data. Yo
s will happen and using the Rb
> reference it is possible to see if the PPS is causing problems or the control
> loop or its the TCXO, it may even be possible to use the recorded data as
> input for simulation to test if it is possible to improve the loop parameters.
> Erik.
>
>
Hi
If simulation is going to be precise, you need a pretty good noise
model for all of the various things that get in the way. You can come
up with those models, but it isn’t going to be easy. Generally, once
you get the device running, you switch to working with it rather than
doing simulation.
Hi
> On Mar 3, 2022, at 3:36 PM, Erik Kaashoek wrote:
>
> The GPSDO I'm building started with frequency locking but now I'm adding
> phase locking so the time stamping counter can be on GPS time.
> A first version works with a PI controller setting the vc-tcxo Vtune DAC
> based on the phase
A using EXT +/-time gate/arm, with a sample size of 1000. 57600
> 1-second
> measurements were collected, starting on 3/2/04 4:15pm The modified root
> Allan variance was
> computed to give the graph shown above.)"
>
> On Thu, Mar 3, 2022 at 2:17 PM Bob kb8tq wrote:
>
Hi
FEI tended to “hang on” to model numbers through many generations
of devices. I suspect this made marketing a lot easier. It does not make
working out “what do I have here” very easy these many years later.
They never intended any of these devices to be field repairable. Their
customers
Hi
Over the years, there have been many generations of GPS gear.
Even today there is a range of stuff out there. Any time you dive into
this or that box there is a long list of things to wonder about.
1) Does it expect a 50 db, 30 db, 20 db or 12 db gain antenna? Some
front ends are designed
Hi
The main disadvantage (if you are after ADEV) is the pre-processing
that takes out the noise you are trying to measure. Getting the repeat
rate so that you actually got samples once a second (after all the overhead
and processing) would be a challenge.
Bob
> On Mar 3, 2022, at 2:28 AM, Mete
Hi
A GPSDO with a poor sky view will not do well. They are designed with the
“assumption” that you will have a good lock unless the antenna gets hit by
lightning ( or some other catastrophe ).
Assuming you are south of Hadrian’s Wall, you will have GPS sats overhead
at least occasionally. The
Hi
> On Mar 1, 2022, at 9:28 AM, Lux, Jim wrote:
>
> On 3/1/22 12:54 AM, John Moran, Scawby Design wrote:
>> David - thanks for the reply, but these seem designed for SDR and I wanted
>> 1pps. Nice and cheap though.
>>
>> Paul - thanks too; it seems that you are saying that the performance
Hi
There are multiple categories of GPSDO:
1) eBay surplus items pulled out of one or another piece of gear.
They are commercially made for whatever application that gear needed.
Typically they have a 10 MHz and 1 pps output. The normal target market
is telecom so the phase noise may not be
Hi
> On Feb 27, 2022, at 5:20 PM, Hal Murray wrote:
>
>
> kb...@n1k.org said:
>> Since there is a quick / simple / (near) zero cost solution ( look at a delta
>> to a second pps stream) crossing more sources of trouble off the list is
>> normally a pretty easy decision.
>
> I can see how
lculations are phase stable.
>
>
> On Sun, Feb 27, 2022, 18:19 Bob kb8tq wrote:
>
>> Hi
>>
>> If your goal is an ADEV measurement, you will need to tag the
>> edges against a second “stable” PPS signal. A sequence of period
>> measures can get you in
Hi
If your goal is an ADEV measurement, you will need to tag the
edges against a second “stable” PPS signal. A sequence of period
measures can get you into issues related to round off problems.
Bob
> On Feb 27, 2022, at 11:27 AM, Erik Kaashoek wrote:
>
> But why can't you measure the 1 s
Hi
If both signals arrive at the same time, many devices get a bit confused.
Many counters run into this same basic issue.
One work around is to “offset” one of the PPS signals. The cable delay
feature on the typical GPS module will let you do this over at least a
couple microseconds. For many
HI
> On Feb 26, 2022, at 11:36 AM, Erik Kaashoek wrote:
>
> Magnus, Bob,
> Thanks for the replies.
> @Magnus, I need to study your input a bit longer. What I currently fail to
> understand is : Should there be a low pass filter with a 1/100 s corner
> frequency in series with the Vtune when
Hi
> On Feb 25, 2022, at 10:18 AM, Erik Kaashoek wrote:
>
> Inspired by the gpsdo simulator written by Tom Van Baak I am trying to use
> simulation to validate the PID loop parameters for a cheap and simple GPS
> referenced timer/counter I'm building.
> The following one hour measurements
Hi
The oscillator is a “works or it doesn’t” sort of thing. Frequency and output
level usually are close enough to do what is needed.
Bob
> On Feb 25, 2022, at 3:10 AM, Julien Goodwin
> wrote:
>
> This afternoon I swapped the fixed resistor that should have been a trimpot
> back to a
Hi
If the unit has been off long enough ( could be decades ….. ) there is a lot
about the GPS system that it really has no way of knowing. It will have to
grab a full almanac and the ephemeris data from whatever it might happen
to be able to download it from. Since the data rate on GPS is mind
Hi
Best guess:
Your 10 MHz (for whatever reason) is being turned into a fast edge
square wave. That’s dumping current spikes into the supply and ground
on your board. You have a really wide spectrum as a result ( usually
well up into the GHz region).
That “stuff” is going here / going there.
Hi
I suspect that somebody somewhere in the documentation
process got accuracy and resolution a bit crossed up.
Resolution would be pretty easy to observe.
In a broad sense, to be accurate to 1/2 ns, the time base in
the card would need to be pretty good. Even with a good
onboard reference,
Hi
If you go back in the archives, there have been a number of folks
who have headed off on a “design my own” ( = not build a kit) GPSDO
projects. Many have fiddled a bit and dropped the idea. The ones that
have kept up and actually built something they know works have all
wound up shopping for
to be tough.
Can you build this or that from scratch? Sure you can. Being sure that it does
indeed
work correctly .. not so easy.
Bob
> On Feb 19, 2022, at 8:02 PM, Attila Kinali wrote:
>
> On Fri, 18 Feb 2022 19:48:21 -0500
> Bob kb8tq wrote:
>
> I would not be so ne
eiver of questionable provenance. Since then I've gathered an HP
> 10811D and I have an HP E1938A coming (I think), so I have only so far
> gathered some essential components that I hope are competent.
>
> On Sat, 19 Feb 2022 at 07:13, Bob kb8tq wrote:
>>
>> Hi
>>
>>
Hi
Sounds like you might want to try a different TCXO. Or even
try an OCXO. Even with a good TCXO, 1x10^-9 accuracy is
a stretch. I’m assuming we’re talking frequency accuracy so
the usual “one sigma” time accuracy not the overriding number.
GPS module “output jitter” forces you to a fairly
unit in 1998 using his PCB and a Motorola
> UT+.
> It has been running almost continuously since then - almost 25 years.
> It has been thru several HP 10811 and 10844 oscillators during that time.
>
> Even though Brooks is SK his GPSDO is still running.
>
> Regards.
> Bill, NL7F
>
hat this is another reality of DIY ham radio these days:
> 75 years ago, you just needed a (wooden) bread board, some brass
> screws, and a tube. Now you need spectrum analyzers, SMT microscopes,
> fantastic eyesight and hand-eye coordination, it just isn't as easy
> anymore.
>
&
Hi
If it’s a sub $1 device, it’s pretty much guaranteed that it has digital
“stuff” inside it. That circuitry will generate blips and pops totally
independent of any attempt it makes at compensation. If it “wakes
up” this or that digital sub section every 107.34 seconds, you get
an internal
Hi
First question would be “why?” ( or more properly, what are you trying
to accomplish? / what are the project goals? )
You can buy any one of a number of GPSDO’s on eBay for very little money.
They come in a range of “flavors” from a range of suppliers. You can
get OCXO based units. You can
t;
>
> Best Regards,
>
> Bill
>
>
> On Sat, Feb 12, 2022, 7:21 AM Bob kb8tq wrote:
>
>> Hi
>>
>> You just might find that kit will drop into a 5065 with minor
>> mods…..
>>
>> Bob
>>
>>> On Feb 12, 2022, at 8:39 A
Hi
You just might find that kit will drop into a 5065 with minor
mods…..
Bob
> On Feb 12, 2022, at 8:39 AM, Ke-Fong Lin wrote:
>
> Hi everyone,
>
> Last month, I bought a 10811-60109 on ebay, it was sold with the
> complete oscillator assembly for a 5061A/B cesium clock.
> I bought it for
Hi
> On Feb 11, 2022, at 6:25 PM, Joseph Gwinn wrote:
>
> On Fri, 11 Feb 2022 03:30:36 -0500, time-nuts-requ...@lists.febo.com
> wrote:
> time-nuts Digest, Vol 214, Issue 12
>
>> Date: Thu, 10 Feb 2022 17:28:20 -0500
>> From: Bob kb8tq
>> Subject:
Hi
The various “sub species” of 10811’s were a test and select item done
on the HP line. When they found enough to fill the need for this or that
part number they stopped testing. Some of the normal parts could indeed
be better than the selected versions.
We are now a *long* way past when this
Hi
> On Feb 10, 2022, at 4:44 PM, Joseph Gwinn wrote:
>
> On Thu, 10 Feb 2022 03:30:33 -0500, time-nuts-requ...@lists.febo.com
> wrote:
>> time-nuts Digest, Vol 214, Issue 11
>
>>
>
>> Message: 13
>> Date: Wed, 9 Feb 2022 15:18:36
Hi
I think you may be heading a bit off track digging into the 5120. The
53100a has a very different “heritage” than the TSC gear. The 5330
“TimePod” would be a better thing to dig into to see its history. I’m
guessing 52100A is a typo.
The .TIM files are generated by TimeLab so that’s a good
cope with that.
> Then later, using other module types, GPRMC became GNRMC to cope with
> Glonass etc. so that was another change needed.
>
> Andy
> www.g4jnt.com
>
>
>
> On Wed, 9 Feb 2022 at 15:49, Bob kb8tq wrote:
>
>> Hi
>>
>> In terms of upg
Hi
In terms of upgrading the GPS module(s):
You might want to look at just *what* NMEA messages are being used.
While the format is “standard” it’s not quite dead nuts in some cases.
Vendors get to add this and that and it still is NMEA. Converting from
one family to another is not always
Hi
> On Feb 8, 2022, at 11:16 PM, ed breya wrote:
>
> Sorry I haven't been proactive on this. My main PC crapped out last week in a
> big way. I've been doing almost a total rebuild on it. Just got internet and
> email working this morning, followed by printer problems.
>
> Regarding the
Hi
Just a guess:
Single band GPS with a preamp that runs on 12V (or 5V). Gain around
30 db.
Bob
> On Feb 8, 2022, at 3:31 PM, John Miller via time-nuts
> wrote:
>
> Hey all,
> I'm looking for a specs sheet for an antenna i recently got my hands on. It's
> marked Topcon on the top, II
Hi
On a lot of PLL’s noise is as much an issue as discrete spikes
( = spurs ). If one widens the definition out to include noise then
things get even more complicated.
Simulation !!! There are free programs out there and “pay” stuff
as well. If you are starting from scratch, they likely will
put of phase
> detector). There are a few equations to estimate the reference spurs but I'm
> chasing the source material.
>
> Regards,
> Vasco Soares
>
> -Original Message-
> From: Bob kb8tq
> Sent: 6 de fevereiro de 2022 19:08
> To: Discussion of precise ti
Hi
Just to clarify:
“Sub Harmonics” is a term often used to describe spurs at carrier / N
where N is pretty small. If N = 4 you would be looking for spurs at
0.25, 0.5, 0.75, 1.25, 1.5 and 1.75 times the carrier frequency. This
would be a common way to talk about them in the context of “sub
Hi
Any time you relocate things (even by 10m) it’s a really good idea to
do a resurvey. The same is true if the GPS module gets replaced. Yes
this is a “Timenut” talking :). Clicking on the resurvey button isn’t
all that big a deal.
Bob
> On Feb 4, 2022, at 8:11 AM, Hal Murray wrote:
>
>
>
Hi
Pretty much *any* counter can measure 1x10^-9 if you leave the gate
open long enough. Gate time matters. One can *assume* a 1 second
gate time, but that’s not always the case. ADEV suffers from this same
“unstated time” issue.
In “HP” terms 1x10^-9 at 1 second is roughly a 5335 from back in
Hi
Without knowing the ultimate “target use” for this system, it is
very hard to guess what will or will not be a problem.
As an example, lets say we’re “building an engine”:
Ok, engines go into chain saws. Engines go into dump trucks.
Engines also go into airplanes. Some are run in
e interaction to start? With a 200MHz clock,
> does that leave some space for low frequencies (but not so low it does not
> matter anymore) to move the clock away from the danger zone?
> Erik
> On 1-2-2022 14:50, Bob kb8tq wrote:
>> Hi
>>
>> The main point about “added h
Hi
Quick couple hints on basic Rb operation:
1) The cells / lamps need to be at the proper temperatures. Oddly enough
they don’t all work when at the same temperature. There often are two oven
controllers in there to accomplish this.
2) The synthesized “interrogation signal” needs to be
of the events to avoid dead bands once this harmonic
> relations is detected.
>
> On 31-1-2022 22:25, Bob kb8tq wrote:
>> So: Is this sort of resolution good enough for your application? If not,
>> there
>> are well known techniques to improve on it. They are not craz
Hi
What you run into on a lot of setups are dead bands. You get a series
of (effectively) same / same /same /same sample groups. Applying math
to them gives you the (obvious) result … everything is perfect.
If you have (say) a 200 MHz clock, your data will be “chunked” into 5 ns
spaced buckets
Hi
> On Jan 31, 2022, at 2:32 PM, Erik Kaashoek wrote:
>
> Thanks all for the good input.
>
> @Magnus, I need some time to understand the math as it has been over 30
> years since when I used to do this kind of math.
> There is no intention to store the collected captures, only to present a
>
Hi
One thing that is still unclear: Why do you have two clocks tagging
the events?
You have a simple crystal oscillator and are looking at 0.1 seconds.
That oscillator likely “bounces around” ( = has a noise floor) at about
1x10^-8 or so. Indeed, your “perfect” clock likely has similar
HI
> On Jan 31, 2022, at 10:23 AM, Erik Kaashoek wrote:
>
> There was a small error in my previous post
>
> Here are the complete and corrected numbers
> Below table shows:
>
> Event counter(Y) : The exact count of events since the start of the counter
> captured at the time of the event.
>
Hi
One would guess that they delay going “full power” so as not to hammer the
main power supply quite so hard at start up.
Bob
> On Jan 29, 2022, at 2:27 PM, Tom Holmes wrote:
>
> HI Ed & Ed...
>
> Thanks for the plot. The dive towards zero just before the spike s
> surprising; maybe a
Hi
There also are logic families that are 5V tolerant when run off of 3.3V. That
makes finding a “translator” the same as finding any chip from that family.
This may or may not make things easer to do / easier to find.
One of many families is the NC7SZ series. One common gate:
hing like this?
> https://www.youtube.com/watch?v=6SHGAEhnsYk=PL3XBzmAj53RlkM2_xRq2NodFjFtBrgzx0=11=1s
>
> Ray
>
> On 2022-01-25 12:11, Bob kb8tq wrote:
>> Hi
>> The original idea was a transmitter with a 20m range. The “check
>> the regs” are aimed at that sort of
f jail :)
>>
>> Bob
>>
>>> On Jan 25, 2022, at 12:21 PM, Lux, Jim wrote:
>>>
>>> On 1/25/22 7:52 AM, Bob kb8tq wrote:
>>>> Hi
>>>>
>>>> I would check the local rules and regs before you put money
>>>>
5/22 7:52 AM, Bob kb8tq wrote:
>> Hi
>>
>> I would check the local rules and regs before you put money
>> into one of these gizmos. At least by the rules over here, this
>> sort of thing might get you in trouble.
>
> Setting a watch 30 cm away would require
Hi
I would check the local rules and regs before you put money
into one of these gizmos. At least by the rules over here, this
sort of thing might get you in trouble.
Bob
> On Jan 25, 2022, at 5:29 AM, Anthony Dunne wrote:
>
> G'day time nut friends
>
> I wonder if one of you could point
Hi
First off, yes, standard deviation is a pretty good way to look at what a
counter
is doing. Reducing the answer to time ( = picoseconds ) is usually the easy way
to look at the data.
Next up, counters have a *lot* of things that impact what they do. The slew rate
of the input signal is a
Hi
On a similar note:
If the transformer works well up to 600Hz, isn’t that high enough to capture
anything that actually is grid related (as opposed to local to your home /
neighborhood )?
One could easily argue that the other end is the pinch point. There may well
be interesting things
Hi
One as yet unaddressed question:
When you see “something odd” on your power monitor. What is the
likely source?
For stuff past a few hundred hertz, my bet is that the source is more
likely to be “local” than “remote”. There are things like lightning hits
that will put a nice spike on the
Hi
Probably the most direct route would be to simply buy a GPSDO with
the “normal” 10 MHz output. Then build a “synthesizer” to convert that
10 MHz into whatever the radios need.
Since GPSDO’s need to run for a while (days …) to achieve reasonable
accuracy, something based on a light weight
Hi
None of these transformers are designed for audio use. The same is true
of the various inductors and capacitors mounted up on power poles to try
to phase correct the distribution process. Pretty much all of them are “out
in the wild” and thus exposed to fairly large temperature swings.
All
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