[time-nuts] Re: Noise down-converter project

[Robert LaJeunesse]

FYI there are some rather flat video filter ICs that have been made in the 
past. The 6th order HMC1023LP5E is tunable, at its 28MHz setting its flat then 
down 0.1dB in the teens, down 0.35dB at 20 MHz. That same setting is 60dB down 
at about 90 MHz. It is also a dual part, designed for matched I-Q filtering.

Bob LaJeunesse

> Sent: Sunday, May 15, 2022 at 5:29 PM
> From: "ed breya" 
> To: time-nuts@lists.febo.com
> Subject: [time-nuts] Noise down-converter project
>
> Continuing on, the mixer's output looks amazingly good. The filter's,
> not so much. I have the IF now going directly to the SA input - no pads,
> no filters, no nothing, except some SMB cable/adapter stuff, and about
> 20 feet of BNC cable. It looks great, letting the SA do the filtering.
> The low end is a beautiful down-converted replica of the 50-90 MHz noise
> signal.
>
> I can't make high precision measurements here - most are eyeball
> estimates from the SA screen, but everything is in the right ballpark,
> and makes sense. The amplitude measurements depend on the SA's IF RBW
> setting, which is 3 MHz maximum. The measured levels agree well with
> different RBW settings. The video BW also affects it some, since extra
> filtering is needed sometimes to smooth the curves.
>
> The spec of the 4647 says the effective noise BW is 48.2 MHz. The IF
> passes through the -3 dB point near 24 MHz, in close agreement. The
> level is very flat (no discernible deviation), to around 20 MHz, where
> it just visibly starts to curve into the band edge. The maximum PSD
> appears to be around -80 to -83 dBm/Hz, estimated from the displayed
> levels at different RBWs.
>
> So, the desired signal is wonderful, if only it didn't include
> everything else above. What I need is a very good LPF to get the job
> done - the usual problem.
>
> The actual filter I've been using does a good job on the higher
> frequencies, but is poor on flatness. It has about 2-3 dB p-p passband
> ripple, with periodicity around 5-7 MHz. I've tried various padding
> arrangements at both ends, all of which tend to flatten it only a little
> bit at best. Looking at it with the TG/SA setup, the character is
> intrinsic to filter, and not due to just its reaction to the mixer and
> cabling and such.
>
> I hate building filters. Designing them in principle is easy, with all
> sorts of available tools online, but actually rounding up the real parts
> (and their parasitics) and physical implementation is a PITA. But, I
> suppose I'll have to do it eventually for this project. I know how nice
> it can be, with the right filter, but for now, I'll have to go with what
> I have.
>
> This particular filter is a packaged module type that I've had for a
> long time, and used in many experimental setups. In fact, I had to
> borrow it from its commitment to another project. Despite its
> limitations, it can be very handy, and it is very simple inside, so I'd
> like to replicate it for other uses. I plan to open a thread about this
> as a separate issue.
>
> In the mean time, it will be for this noise project, and I'll have some
> more to report, so next up will be the low frequency/DC aspects.
>
> Ed
>
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe send an email to time-nuts-le...@lists.febo.com
>
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-le...@lists.febo.com

[time-nuts] Re: Trimble Thunderbolt question

[Robert LaJeunesse]

Paul,

Take a look at page http://www.leapsecond.com/pages/tbolt/photos.htm

The fourth pic down in the right column shows the power connector soldered 
directly to the PCB (upper left edge, by C6).

If your power 6 pin header is in the same spot then it is highly probable the 
pinout is identical. If the traces on your unit match those of the pic then its 
almost a certainty.

Bob L.

> Sent: Sunday, April 10, 2022 at 9:43 AM
> From: "N1BUG" 
> To: time-nuts@lists.febo.com
> Subject: [time-nuts] Trimble Thunderbolt question
>
> Hi,
>
> Long time lurker here, getting ready to upgrade to a Trimble Thunderbolt
> for my 10 MHz reference. I have a question about the power connector pinout.
>
> I acquired a 48051-61 plain PCB presumably requiring +5V, +12V, -12V. I
> have no documentation. Mine has a 6 pin header, NOT the Molex connector
> described here:
>
> http://www.leapsecond.com/pages/tbolt/power.htm
>
> Can I safely assume pin assignments are the same?
>
> Thanks,
> Paul N1BUG
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
> email to time-nuts-le...@lists.febo.com
> To unsubscribe, go to and follow the instructions there.
>
___
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
email to time-nuts-le...@lists.febo.com
To unsubscribe, go to and follow the instructions there.

[time-nuts] Re: Another reason to monitor line frequency :) - My AC measurement project & question

[Robert LaJeunesse]

One thing that has helped me build survivable designs is utilizing high 
impedance inputs, which means adding a buffer before an ADC pin if need be. 
Most IC inputs clamp to the supply, and can withstand a milliamp or two of 
current with out damage. ADCs typically want a low impedance source, so a 
buffer powered from the ADC's supplies guarantees no overvoltage that can cause 
excess current. A high resistance in series with the buffer input limits its 
current under transient conditions, providing the needed safety factor for 
noise spikes. Split that resistance up and add a low-leakage silicon diode 
(e.g. BAV199) to the supply and now the input is seriously protected with 
supply on, or off.

One problem with TVS diodes on signal inputs is that they limit to an absolute 
voltage, not one relative to the supply of the device to be protected. The 
degree of protection varies whether the device is powered or not. You must 
design for the unpowered situation, else things go poof when power isn't 
sequenced right. That will happen sooner or later.

Bob L.

p.s. A note about capacitive coupling: Yes, well proven reliable for carrier 
current systems BUT... with a sub-octave signal bandwidth far, far removed from 
the power fundamental. This application is multi-octave and includes the power 
supply fundamental. Big difference in application.

> Sent: Saturday, January 22, 2022 at 2:15 PM
> From: "willl will" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Subject: [time-nuts] Re: Another reason to monitor line frequency :) - My AC 
> measurement project & question
>
> On 1/21/22 7:00 PM, Robert LaJeunesse wrote:
> > Stick with the transformer. The use of a capacitive divider is predicated
> on the line waveform always being a sine wave. Dream on! All it takes is
> one good spike down the line, maybe only 20-30V amplitude, and your
> capacitive divider passes it right on to that ADC that has a much lower
> (3.3V?) limit. Guess what goes poof?
> >
> > Bob L.
>
> I am concerned about this even with the transformer, so I've added Ti's TVS
> chips & hookup the transformer after my UPS surge protection plug in the
> previous project.
> Definitely need to step up the protection level using an NTC resistor or
> something like that to handle mains voltage directly. Or offload the
> concern to a surge protection plug.
>
> Will
___
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
email to time-nuts-le...@lists.febo.com
To unsubscribe, go to and follow the instructions there.

[time-nuts] Re: Another reason to monitor line frequency :) - My AC measurement project & question

[Robert LaJeunesse]

Stick with the transformer. The use of a capacitive divider is predicated on 
the line waveform always being a sine wave. Dream on! All it takes is one good 
spike down the line, maybe only 20-30V amplitude, and your capacitive divider 
passes it right on to that ADC that has a much lower (3.3V?) limit. Guess what 
goes poof? 

Bob L.

> Sent: Friday, January 21, 2022 at 8:48 PM
> From: "Lux, Jim" 
> To: time-nuts@lists.febo.com
> Subject: [time-nuts] Re: Another reason to monitor line frequency :) - My AC 
> measurement project & question
>
> On 1/21/22 4:43 PM, willl will wrote:
> > Hi everyone,
> >
> > I have an recently finished project that also measuring AC waveform, full
> > description here:
> > https://github.com/will127534/RaspberryPiAtomicNixieClock/wiki
> >
> > Basically using an AC transformer and Ti's ADC8681 @ 50Khz sampling rate.
> >
> > This year I'm working on a earthquake sensor + AC mains monitor system (In
> > an earthquake prone area, AC mains frequency will fluctuate by power
> > generator and machine emergency stop like this one:
> > https://twitter.com/kuriuzu/status/1360602496821911553).
> >
> > I want to improve AC measurement. Apart from the ADC sampling speed upgrade
> > (previously bottlenecked by the SPI connection to FPGA). I'm currently
> > debating about whether or not to bypass the transformer. How does the
> > distortion of an AC transformer impact the accuracy of mains waveform and
> > frequency? I'm not sure if it is worth it to go through the mains voltage
> > safety requirements.
> 
> You can use a capacitorsget your galvanic isolation, and a CR voltage 
> divider with minimal waveform distortion. Pick a burden current (say, 1 
> mA) and for 120V line, you need 120k impedance at line frequency 60Hz
> 
> X = 1/(377*C) --> C = 1/(377 * 120E3)  = 22 nF
> 
> Say you want ~100:1 ratio? so 22 nF in series with 1.2k  (or 2.2uF) 
> would do nicely. Then feed your high Z ADC with a couple 0.1 uF 
> capacitors from the ends of the 1.2k.
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
> email to time-nuts-le...@lists.febo.com
> To unsubscribe, go to and follow the instructions there.
___
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
email to time-nuts-le...@lists.febo.com
To unsubscribe, go to and follow the instructions there.

[time-nuts] Re: HP 5065A, no 2nd harmonic.

[Robert LaJeunesse]

Drops in a hole in the PCB. I doubt that you could buy that exact one, it is 
unusual and probably custom. Pin terminals and fork terminals are much more 
common. The closest I could find to the pictured one are from Cambion 
Electronics, which has (smaller diameter) hollow PTFE insulated press-mount 
terminals available. No similar item shows at Concord Electronics, the other 
common source.

http://www.cambion.com/solder_terminals_ptfe_insulated_press_mount3_catalogue_parts_list.aspx

This part has about enough room for 2, maybe 3, leads: 
http://www.cambion.com/catalogue_page.aspx?ID=278

Bob L.

> Sent: Tuesday, November 30, 2021 at 7:19 PM
> From: "Hal Murray" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Cc: "Hal Murray" 
> Subject: [time-nuts] Re: HP 5065A, no 2nd harmonic.
>
>
> lajeune...@mail.com said:
> > Judging from the teflon solder cup used I suspect insulation resistance is a
> > critical parameter.
>
> Could somebody please give me a lesson or pointer or ...
>
> I noticed something interesting in the picture.  Is that just a ring on the
> surface, or a part that drops into a big hole in a PCB, or ???
>
> Google for "teflon solder cup" didn't find anything interesting.  What would I
> search for if I wanted to buy one?
>
>
> --
> These are my opinions.  I hate spam.
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
> email to time-nuts-le...@lists.febo.com
> To unsubscribe, go to and follow the instructions there.
>
___
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
email to time-nuts-le...@lists.febo.com
To unsubscribe, go to and follow the instructions there.

[time-nuts] Re: HP 5065A, no 2nd harmonic.

[Robert LaJeunesse]

That film cap does look a little cooked. Since it is a 2uF 20% 50V part a more 
common 2.2uF 10% 63V part would likely be an acceptable substitute, and 
basically still within overall tolerance. Judging from the teflon solder cup 
used I suspect insulation resistance is a critical parameter. Be sure to clean 
away any flux remaining after soldering.

Bob L.

> Sent: Tuesday, November 30, 2021 at 9:36 AM
> From: "Jared Cabot via time-nuts" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Cc: "Jared Cabot" 
> Subject: [time-nuts] Re: HP 5065A, no 2nd harmonic.
>
> ...
>
> Also, I noticed that a 2.0uF, 20% film capacitor in there is looking like 
> it's had a bit of heat-stroke.
> It measures 2.119uF, 0.22ohm ESR, with a dissipation of 0.004 @ 40V, @ 1kHz, 
> so it seems to test ok.
> Does this look like it needs to be replaced (picture link below)? I can't 
> find the same part on Digikey/Mouser, but it seems like Keysight have them as 
> 'orderable' status.
> Details are as follows: P/N: 0160-4947 Part Description: Capacitor-Fixed 2uF 
> +-20PCT 50V polyester metallized THT
>
> https://i.imgur.com/aZ0KUD8.jpg
>
> Thanks!
> Jared
___
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
email to time-nuts-le...@lists.febo.com
To unsubscribe, go to and follow the instructions there.

[time-nuts] Re: General Radio 1105-A Frequency Measuring Equipment, parts wanted.

[Robert LaJeunesse]

   The mains connector proper is readily available:
   https://www.ebay.com/itm/201639994813?chn=ps

   But the snap-on metal backshell is less available:
   https://www.etsy.com/listing/62249/backshell-for-amphenol-78-and-86
   -series

   Shown here with back clamp:
   https://www.etsy.com/listing/621285791/back-shell-for-amphenol-78-serie
   s

   Also here "Amphenol Metal Backshell":
   https://www.surplussales.com/Tube-Sockets/TubeSkts-3.html

   Bob L.
   > Sent: Monday, August 23, 2021 at 9:15 AM
   > From: "Stijn" 
   > To: time-nuts@lists.febo.com
   > Subject: [time-nuts] Re: General Radio 1105-A Frequency Measuring
   Equipment, parts wanted.
   >
   > Seems that the pictures got scrubbed:
   >
   > Links:
   >
   > The equipment I am working on:
   > [1]https://www.pe1rks.nl/plaatjes/GR_1105A/IMG_0030.JPG
   >
   > The GR 774 connectors that I am after:
   > [2]https://www.pe1rks.nl/plaatjes/GR_1105A/IMG_0115.JPG
   >
   > The mains connectors that I am looking for need to fit these:
   > [3]https://www.pe1rks.nl/plaatjes/GR_1105A/IMG_0116.JPG
   >
   > The oscillator module that I would like to replace:
   > [4]https://www.pe1rks.nl/plaatjes/GR_1105A/IMG_0013.JPG
   >
   > Sincerely,
   >
   > Stijn
   >
   > Op 23-8-2021 om 15:04 schreef Stijn:
   > > Fellow Time-nuts,
   > >
   > > I have for some time a General Radio 1105-A and I have started to
   > > resurrect this two rack Frequency Standard combined with Frequency
   > > Measuring Equipment.
   > >
   > > There are some repairs to be made and some units require some more
   in
   > > depth restoration, but to be able to complete this task and get all
   > > working like it once should I need some parts.
   > >
   > > What I need are some General Radio 774 connectors, 8 to be exact:
   > >
   > > I am also in need for 6 of the connectors fitting this mains entry:
   > >
   > > And the worst part is the Piezo Oscillator, the Quartz bar is there
   and
   > > in good condition the oven is also working. But the oscillator
   circuit
   > > has been heavily modified.
   > >
   > > Instead of the original bridge circuit they have build a totally
   > > different oscillator and I can't get this to work.
   > >
   > >
   > > So here are my questions:
   > >
   > > Does anybody have or know a supplier for the needed connectors?
   > >
   > > Is there someone out there who has just the Oscillator module for
   the
   > > Piezo-Electric Oscillator and is willing to sell and ship this?
   > >
   > > Sincerely,
   > >
   > >
   > > Stijn Nestra
   > >
   > >
   > > ___
   > > time-nuts mailing list -- time-nuts@lists.febo.com -- To
   unsubscribe
   > > send an email to time-nuts-le...@lists.febo.com
   > > To unsubscribe, go to and follow the instructions there.
   > ___
   > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe
   send an email to time-nuts-le...@lists.febo.com
   > To unsubscribe, go to and follow the instructions there.
   >

References

   1. https://www.pe1rks.nl/plaatjes/GR_1105A/IMG_0030.JPG
   2. https://www.pe1rks.nl/plaatjes/GR_1105A/IMG_0115.JPG
   3. https://www.pe1rks.nl/plaatjes/GR_1105A/IMG_0116.JPG
   4. https://www.pe1rks.nl/plaatjes/GR_1105A/IMG_0013.JPG
___
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
email to time-nuts-le...@lists.febo.com
To unsubscribe, go to and follow the instructions there.

[time-nuts] Re: test message

[Robert LaJeunesse]

   It works.
   > Sent: Tuesday, June 22, 2021 at 1:26 PM
   > From: "Mark Sims" 
   > To: "time-nuts@lists.febo.com" 
   > Subject: [time-nuts] test message
   >
   > My email address book got corrupted. Hopefully this will work...
   > ___
   > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe
   send an email to time-nuts-le...@lists.febo.com
   > To unsubscribe, go to and follow the instructions there.
   >
___
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
email to time-nuts-le...@lists.febo.com
To unsubscribe, go to and follow the instructions there.

[time-nuts] U-blox teaser

[Robert LaJeunesse]

FWIW. No detailed content, and a rather quick read. "Five key trends in GPS".

https://www.u-blox.com/en/blogs/insights/five-key-trends-gps

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

[time-nuts] Quick tour of CHU

[Robert LaJeunesse]

FYI  https://www.radioworld.com/global/chu-canadas-time-station

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] L1/L2 survey antenna $125 new

[Robert LaJeunesse]

Dana, no plans to buy. Just put up my L1 antenna last weekend.

Bob L.

> Sent: Friday, November 13, 2020 at 7:26 PM
> From: "Dana Whitlow" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Subject: Re: [time-nuts] L1/L2 survey antenna $125 new
>
> I quote the description on the SparKfun page via the WIndows clipboard:
>
> "Note: This antenna has a TNC Male RP connector found on nearly all
> surveying antennas. We recommend a TNC Male RP to SMA adapter
> <https://www.amazon.com/DGZZI-2-Pack-Coaxial-Adapter-Connector/dp/B06ZZGGWBS>
> or
> cable when using with our GNSS receivers."
>
> But the photo on the site appears to show a receptacle, not a pin, for the
> center conductor, hence
> a standard female configuration.  So unless the thread is left-handed,
> which I really can't tell,
> this is a standard (not RP)* female* connector.  That's my story and I'm
> sticking to it!
>
> Bob, are you by chance thinking of buying one of these?  If so, please let
> us know which it
> is right away when it arrives.
>
> Dana
>
>
> On Fri, Nov 13, 2020 at 1:34 PM Robert LaJeunesse 
> wrote:
>
> > Just spotted this: https://www.sparkfun.com/products/17382
> >
> > Datasheet:
> > https://cdn.sparkfun.com/assets/6/e/a/9/2/BT-147_GNSS_Antenna_Datasheet.pdf
> >
> > Chokeplate design, 40dB LNA, TNC connector
> >
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to
> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
> >
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

[time-nuts] L1/L2 survey antenna $125 new

[Robert LaJeunesse]

Just spotted this: https://www.sparkfun.com/products/17382

Datasheet: 
https://cdn.sparkfun.com/assets/6/e/a/9/2/BT-147_GNSS_Antenna_Datasheet.pdf

Chokeplate design, 40dB LNA, TNC connector

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Query about insulated coax panel connectors?

[Robert LaJeunesse]

If panel and connector sizes permit a small single hole panel mount connector 
can be insulated with a fiber shoulder washer and a flat fiber washer.
https://www.keyelco.com/category.cfm/Shoulder-Washers-Bushings/Fibre-Shoulder-Washers/id/813
https://www.keyelco.com/category.cfm/Washers/Nylon-Fibre-and-Steel-Washers/p/448/id/712/c_id/714

Alternately a piece of PCB material with copper removed can become an 
insulating mount, with the connector poking out through an oversize panel hole. 
Yes, now you need to mount the PCB somehow (2-4 screws?). But one piece of PCB 
stock can hold multiple connectors, making that a bit easier.

Bob L.


> Sent: Saturday, October 24, 2020 at 2:24 PM
> From: "AC0XU (Jim)" 
> To: time-nuts@lists.febo.com
> Subject: [time-nuts] Query about insulated coax panel connectors?
>
> Time-nuts:
>
> Having recently run into major ground loop noise issues, I have begun 
> reworking some of my homemade pieces of equipment using insulated coax 
> connectors. My goal is to have one ground connection only in the cases, and 
> that is at the power entry point, either a power cord or the outer terminal 
> of a DIN. I am also installing isolation baluns on inputs and/or outputs.
>
> Insulated BNCs are readily available. Others not so. In some cases, there is 
> not room to install an insulated BNC. I am not finding any insulated SMA, 
> SMC,  SSMA, or SSMC despite googling and searching catalogs.
>
> Does anyone know of a source for insulated small threaded coax panel 
> connectors?
>
> Another option would be a compact insulating bushing that an SMA panel 
> connector, for example, could be mounted in. I am not finding anything like 
> that either...  In fact the ideal solution would be an insulated SMA with an 
> integrated 1:1 balun.
>
> And I am not thinking about using plastic cases - that would introduce a 
> whole other set of problems. I think about my lab area at work where a bundle 
> of dozens of gigabit ethernet cables run through the roof directly over the 
> lab bench - the ambient noise level is quite high.
>
> Suggestions???
>
> The only idea I have some up with is to design something myself, possibly 3-D 
> printed...  Any suggestions about how to get started on something like that?
>
> Thanks in advance-
> Jim


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] New member, new old 4040A with PSU failure

[Robert LaJeunesse]

Tom, have a look at "Super Corona Dope"

https://www.mgchemicals.com/products/conformal-coating/insulation-coatings/4226-super-corona-dope/

Bob L.



> Sent: Saturday, September 26, 2020 at 8:21 PM
> From: "Tom Van Baak" 
> To: time-nuts@lists.febo.com
> Subject: Re: [time-nuts] New member, new old 4040A with PSU failure
>
> 
>
> If anyone on the list has experience with rodents, you'll notice the 4th
> photo of the fts4040 link above shows that a mouse nibbled on the pink
> silicone insulation around the HV connections. So be careful where you
> store your old cesium standards. I'm used to bugs in s/w but rats in h/w
> is a new low. What kind of HV goo should I replace it with?
>
> /tvb

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Chelsea Chronoquartz dividers

[Robert LaJeunesse]

That was the same frequency Chrysler used in their early (70s) quartz car 
"chronometers". The 1981 Chrysler Imperial electronic dashboard used that 
frequency as well.

Bob L.

> Sent: Friday, September 11, 2020 at 1:30 PM
> From: "Bill S" 
> To: "time-nuts@lists.febo.com" 
> Subject: [time-nuts] Chelsea Chronoquartz dividers
>
> A friend has acquired a Chelsea Clock Company Chronoquartz which was
> probably made in the 70's. He has measured the oscillator frequency at
> approximately 4.194304 MHz. He wanted to know what arrangement of
> dividers they used to run the 4 pole stepper motor to step seconds.
> Anybody know?
>
> Thanks,
>
> Bill_S


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] 5 Digit Panel meters

[Robert LaJeunesse]

The similar meters I have are based on the Microchip MCP3421, a tiny 6-pin SOT 
18 bit ADC with internal 2.048V 15 ppm (typ) reference, differential inputs, 
and a PGA. Input span is +/-2.048V at minimum gain to +/-0.256V with a PGA gain 
of 8. So at max gain 1 LSB is about 2uV, although I'd be surprised if it was 
that quiet (the spec at PGA=1 is 1.5uV typical, no max given). Initial accuracy 
is not great at 0.35% max, but that can be trimmed out externally or via 
software. For an 18 bit ADC with a decent reference it's actually a rather good 
deal at under US $2 (qty 25+). Just don't expect it to be an accurate 18 bits 
over a wide temp range, references like that don't sell so cheap.

Bob L.

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 Panel meters
>
> 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 33V. The reference to the DAC is (likely) 5V. You 
> just lost
> nearly 3 bits from that scale mismatch.  At the 5V level, you would be 
> running just over
> 7 of your (ideal) 10 bits. 
> 
> Net result is that you are trying to check a 16 bit gizmo with a not quite 8 
> bit device.
> 
> Bob


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] low power divide by 5

[Robert LaJeunesse]

Makes me think one could use the input signal edge to synchronize a 2N6027 
based programmable unijunction oscillator, thus effecting a divide by 5. 
Unlikely the 6027 would be fast enough for 50 MHz, but maybe a 2 transistor 
equivalent using RF transistors? Output would be nowhere near the 40%-60% 
range, though. Might just have to build one for fun.

> Sent: Thursday, July 02, 2020 at 8:37 AM
> From: "jimlux" 
> To: time-nuts@lists.febo.com
> Subject: Re: [time-nuts] low power divide by 5
...
> I'm surprised nobody has suggested using the 12AX7 or 6J6 dual triodes.


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] low power divide by 5

[Robert LaJeunesse]

Take a look at the "modified" shift-register like counter in the attached jpg 
file. When simulated online it behaved as expected for a divide by 5. I believe 
it also is self-clearing from illegal states, but the other simulator I tested 
that in wasn't good for documenting the design.

Bob L.

> Sent: Tuesday, June 30, 2020 at 6:47 PM
> From: "dschuecker" 
> To: time-nuts@lists.febo.com
> Subject: Re: [time-nuts] low power divide by 5
>
> Hi,
> 
> a divide by five should possible with a synchronous state-machine made 
> of 3 ( sufficiently fast-) JK-FlipFlops.
> 
> All 3 FFs are clocked with the input freq. , the outputs of the FFs are 
> fed back to the the JK-inputs,  the divided freq. is output of one of 
> the FFs.
> 
> Additional constraints: no external ANDs or ORs or NOTs, the 
> state-machine does not get stuck in the 3 unused states.
> 
> This turned out to be a very interesting problem and I do not yet come 
> up with a solution. Maybe there is none. Analytical solutions all 
> failed, I will try a brute force enumeration attack tomorrow.
> 
> lots of fun !
> 
> Cheers
> 
> Detlef
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Frequency division by 81

[Robert LaJeunesse]

Gilles, if I read the Calosso-Rubiola paper correctly a Pi divider is pretty 
much your standard square-wave producing digital divider, such as a 74163 (for 
even divides). There's odd-value (3,5,7) Pi dividers shown at 
https://www.theremin.us/Circuit_Library/symmetrical_digital_dividers.html. What 
the Calosso-Rubiola paper promotes is the Lambda divider, which is depicted in 
figure 2 of the paper.

Bob L. 

> Sent: Friday, June 19, 2020 at 10:27 AM
> From: "Gilles Clement" 
> To: "Poul-Henning Kamp" 
> Cc: "Discussion of precise time and frequency measurement" 
> 
> Subject: Re: [time-nuts] Frequency division by 81
>
> Hi, 
> Could you point me to a practical design example of a Pi divider ?
> 
> 
> Envoyé de mon iPad
> 
> > Le 19 juin 2020 à 08:56, Poul-Henning Kamp  a écrit :
> > 
> > 
> > 
> >> I need to divide the output of an OCXO by a factor D=81 for testing 
> >> purposes. So with minimum added phase noise.
> > 
> > Two stages of divide by 9 PI-dividers ?
> > 
> >   
> > http://rubiola.org/pdf-articles/conference/2013-ifcs-Frequency-dividers.pdf
> > 
> > -- 
> > Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> > p...@freebsd.org | TCP/IP since RFC 956
> > FreeBSD committer   | BSD since 4.3-tahoe
> > Never attribute to malice what can adequately be explained by incompetence.
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] advice sought on basic gpsdo

[Robert LaJeunesse]

While I'm no expert at time, or Arduino yet, the first thing I would look at is 
getting the bootloader to run with not 16MHz, but a 10MHz clock. Not having 
looked at it I don't know if it requires modifying and re-flashing, but it 
might. Now the VCTCXO can clock the Arduino and the Arduino IDE would work 
unmodified. Code the Arduino chip to lock the VCTXCO to GPS 1PPM, and you can 
accurately keep time of day in RAM. As long as you have a valid battery backup 
5V supply just detect the loss of 1PPM (or GPS signal) and freeze the VCTXCO 
control voltage. With some effort the clock can auto-set itself from the GPS 
when the GPS is in a good state. Not simple coding, but doable.

Bob L.

> Sent: Friday, May 08, 2020 at 7:06 PM
> From: "Robert Melville" 
> To: time-nuts@lists.febo.com
> Subject: [time-nuts] advice sought on basic gpsdo
>
> Fellow time nutters:
>
> Any input or advice on the following project would be appreciated.
>
> I want to make a small, portable, batter-operated clock that will
> spend most of its time docked into a charging bay with access
> to a signal from a GPS receiver -- either 1 PPs or 10. MHz.
> The device will have a voltage-controlled TXCO that will be disciplined
> by the GPS input unless the unit is traveling.
>
> I have seen several designs for disciplined oscillators using a uP,
> such as an Arduino or a PIC. The main decision seems to be between
> 1 PPs or 10 MHz as the input. 1 PPs might be preferable because
> not all cheap GPS receivers seem to provide 10.00 MHz out.
> Mostly, I want accurate time but a frequency reference with
> decent phase noise would be useful.
>
> 1. I am tending towards a published design from Lars Walenius, in part
> because
> it uses a familiar uP (an Arduino) but am open to other designs.
>
> 2. What advice to people have on glitch-free switching when
> docking/undocking the unit from the GPS???
> This seems to be something like the de-bouncing problem for a
> push-button.
>
> 3. Has anyone used the Arduino time library withOUT the Dallas RTC chip --
> i.e., some other source of time such as the from the locked oscillator?
>
> 4. Can anyone share experience with conditioning the power going into the
> TXCO -- to what extent can digital noise from the uP or counters
> contaminate the phase noise of the TCXO? Does a separate isolating buffer
> help for the "osc out" port? I have had good success in the past with
> so-called "active bypassing" to deliver very clean power to an oscillator.
>
> Thanks to all for your attention to this message -- I am glad to look at any
> and all possible designs.
> Happy time-keeping!
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Power Supplies

[Robert LaJeunesse]

Steve, you shouldn't need a schematic. Look for a resistor between the output + 
line and the pot that adjusts the voltage. Determine the value and add a shunt 
resistor across it that is maybe 10x the value determined. See if that drops it 
down enough. Adjust the shunt up or down to get the range you want. Also note 
that if this is a linear supply setting it for a lower output voltage range 
will increase dissipation at full load and possibly require better / forced air 
cooling. 

Bob L.

> Sent: Sunday, May 03, 2020 at 9:53 AM
> From: "Steve - Home" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Subject: Re: [time-nuts] Power Supplies
>
> Has anyone found schematics for the Mean Well supplies? I have a couple of 
> 15V 7A ones that will adjust down to 14.1 and I’d like to get them down to 
> the 12-13.8 range. 
> 
> Steve
> WB0DBS


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Power glitch - Sat morning

[Robert LaJeunesse]

There's usually three wires feeding one's house. It's quite possible for just 
one of them to have a bad connection. If you are really unlucky the neutral 
will open, and overvoltage/undervoltage many appliances. The resulting fire 
cost a friend over $10K to repair and replace damaged appliances.

> Sent: Tuesday, March 31, 2020 at 11:26 AM
> From: "Bob kb8tq" 
> To: ch...@chriscaudle.org, "Discussion of precise time and frequency 
> measurement" 
> Subject: Re: [time-nuts] Power glitch - Sat morning
>
> Hi
> 
> I agree that it shouldn’t be something that happens. That’s why half the house
> going dark was a bit weird …..
> 
> Bob
> 
> > On Mar 31, 2020, at 10:53 AM, Chris Caudle  wrote:
> > 
> > On Tue, March 31, 2020 8:28 am, Bob kb8tq wrote:
> >> If you have a two phase circuit, are both phases of interest?
> > 
> > If you are referring to residential power, a single how would be single
> > phase center-tapped, as far as I know you never get two phases to a single
> > residence.  The houses in a neighborhood may be split up among a high
> > power three phase feed, and an industrial facility will have a three phase
> > feed and have to balance the loads within the facility, but  house wiring
> > all assumes single phase (either half of the transformer secondary for
> > 120V loads, or across the full winding for 240V loads).
> > 
> > With that design I would expect there to only be as much difference
> > between the two legs as  you have difference in loading between the two
> > halves of the transformer winding, since they share a common primary.
> > 
> > -- 
> > Chris Caudle
> > 
> > 
> > 
> > 
> > 
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to 
> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
> 
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Lowest Power NTP Server

[Robert LaJeunesse]

If wired Ethernet seems to be the way to go consider the Orange Pi Zero - about 
the cheapest wired Ethernet board available that runs Linux. Ethernet is via 
on-chip MAC and phy, so no USB path delays. 
http://www.orangepi.org/orangepizero/

Plenty of support exists on the web, for example: 
https://lucsmall.com/2017/01/19/beginners-guide-to-the-orange-pi-zero/

Bob L.

> Sent: Monday, December 02, 2019 at 9:56 AM
> From: "Tim Shoppa" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Subject: Re: [time-nuts] Lowest Power NTP Server
>
> Bob, I find that 2.4GHz Wi-Fi UDP latency with ESP8266 will frequently be
> tens of milliseconds and is never/rarely consistent.
> 
> There are specialized non-WiFi 2.4GHz systems for time distribution that
> are far more consistent (possibly even at the tens of microseconds). I
> think several years ago on this list, we were talking about tricking
> commodity WiFi chipsets into doing these but haven't seen anything as of
> late.
> 
> Tim N3QE
> 
> On Mon, Dec 2, 2019 at 8:02 AM Bob kb8tq  wrote:
> 
> > Hi
> >
> > Indeed, if you get up into the “many tens” of  ms, that rules it out in my
> > application.
> > A consistent 90 ms would be ok, you could compensate for that. Random
> > flopping
> > from 4 to 90 … not so much.
> >
> > It seems like that sort of jitter would get in the way of a lot of things.
> > I guess that just
> > shows how little I know about a lot of things :)
> >
> > Bob
> >


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Timebase Replacement - Seiko Epson RTC-72421

[Robert LaJeunesse]

Looking at the datasheet I'd expect finding a drop-in replacement is likely 
problematic. A rather involved RTC module providing seconds out to 100 years. 
(Although it looks a lot like a Seiko RTC chip I used in the late 70s.)  
Emulation would probably require an FPGA approach, or one using a 2-port 
memory, either driven from a more stable clock that, ideally, is GPS 
disciplined. But a full emulation is an involved design, and all you really 
need to do is sync the seconds, so what's simpler?

One possible approach is to try to do a "jam" correction on the fly. With a 
little study on how the module interacts with the rest of the carillon there is 
likely dead time when another controller can take over access to the RTC 
module. Read the seconds, compare to UTC (or GPS) seconds, adjust if needed by 
blipping the 30 second adjust bit (D3 in register CD, see full datasheet link 
below). If GPS is not present, do nothing, assuming GPS will come back before 
the RTC module skews a full 30 seconds. Depending on how the STD.P pin is used 
there may be no need for read access, as it may provide pulse per second or 
minute that could be used for comparison against GPS. In any case register 
access would require an intercept board that multiplexes all the control lines 
such that your added controller can get to the necessary registers. Unless I'm 
wrong (always a possibility) there is no need to access most of the registers 
in the part, simplifying the design. 

Or maybe the chip core matches that external crystal RTC I used years ago 
(sorry, don't remember the Seiko part number offhand). You could then build a 
module replacement without jam logic but with a GPS disciplined 32.768kHz 
oscillator. That would be a much simpler approach for minimal drift.  

Bob LaJeunesse

Found a full datasheet at 
https://www.manualslib.com/download/47987/Epson-Rtc-72421-A.html
 

> Sent: Thursday, October 03, 2019 at 1:00 AM
> From: "Corey Sukalich" 
> To: time-nuts@lists.febo.com
> Subject: [time-nuts] Timebase Replacement - Seiko Epson RTC-72421
>
> Hi all,
> 
> New to the list, but have known of its existence for a while as I know others 
> that have been subscribers.
> 
> My question pertains to a timebase used in a Schulmerich carillon bell tower 
> system from the 1990’s.
> 
> The Seiko Epson RTC-72421 Real Time Clock Module (4-bit) is used, but the 
> clock ends up walking to a noticeable degree (minutes) over a period of 
> months.  Is this expected for the device in question, or could it possibly 
> have a defect?
> 
> Datasheet available here:
> https://support.epson.biz/td/api/doc_check.php?dl=brief_RTC-72421=en 
>   
> 
> From what I can tell it uses an internal oscillator, so it sounds like I 
> would need to find a drop-in replacement or build a module that will replace 
> it with a significantly better time standard.  Any advice is appreciated as 
> to whether could be accomplished without too much trouble.  I’ve repaired a 
> few of these systems over time and there are enough of them still in the wild 
> that it might be worth me fabricating a module for them.
> 
> Also, on the off chance someone is versed in EPROM data recovery or knows of 
> a resource for it, I would appreciate that information as well.
> 
> Regards,
> Corey
> N9WIV
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Clock accuracy

[Robert LaJeunesse]

You might want to consider an LED digital wall clock. I have a homebrew LED 
clock that's going strong after some 46 years of continuous 24/7/365 operation. 
The MM5314 is even a packaging reject unit I grabbed when it was a brand new 
design and I was a mere co-op engineering student working at the factory.

> Sent: Friday, July 19, 2019 at 1:17 AM
> From: "donald collie" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Subject: [time-nuts] Clock accuracy
>
> ... a modified $10 analogue wall clock. Can anybody tell me this : If I live
> another 100 years [Let`s say I take antioxidants ;-)  ] what sort of error
> should I expect in this clock? [I know that it`s better than 1 second per
> day]

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Advantages of GNSS ???

[Robert LaJeunesse]

Bert,

My take on the issue is that Mark Sims had not seen manufacturer documentation 
on how specifically to use the sawtooth correction value. You posted a picture 
of what we now know was an implementation of a use of the correction value. Did 
you have manufacturer documentation on how the value was to be used before you 
did your design? If so, that's what Mark is looking for. Like me, Dana was 
confused by your picture of a GPS assembly, which was not an answer to Mark. 
Knowing Dana personally I'm not surprised he started down the 20 question path, 
and I doubt he was actually offended by your post. 

respectfully,
Robert LaJeunesse

> Sent: Tuesday, July 09, 2019 at 6:26 AM
> From: "ew via time-nuts" 
> To: time-nuts@lists.febo.com
> Cc: ew 
> Subject: Re: [time-nuts] Advantages of GNSS ???
>
> Dana
> This was in response to Mark Sins " I don't think that I have ever seen what 
> to do  with the sawtooth value
>  documented in any receiver documentation"I did this 4 years ago it, is a 
> sawtooth corrected ublox.  First pass. Always do a follow on board but never 
> did any thing with it since there was no interest. We did it part of our 
> GPSDO work but saw no improvement. Sorry my work offends you.I did the same 
> with the Furuno GT and GN-87 without sawtooth since it is only 4 nsec. Ole 
> tested it and we use it with very good results. Again I followed it up with a 
> later design in case there is interest. I will not post the picture of the 
> original one so not to offend you.I will not do a board on the ublox 9 since 
> we are frequency not time nuts and see no need for it. 
> Bert Kehren
> 
> 
> In a message dated 7/9/2019 12:05:14 AM Eastern Standard Time, 
> k8yumdoo...@gmail.com writes:
> 
> One what?  I see that it is a Ublox unit, but see no reference to the
> interesting
> modern units like the 9 series.  Also, I note that the only reference on
> the board
> to "ant" is on the lower right corner, while what I suppose to be the
> actual antenna
> connector appears to be an SMA near the upper right corner.
> 
> And why does it look like several of the components have been resoldered
> or replaced or something?
> 
> Dana
> 
> 
> On Mon, Jul 8, 2019 at 8:00 PM ew via time-nuts 
> wrote:
> 
> > Well now you can see one
> > Bert Kehren
> >
> >
> > In a message dated 7/8/2019 7:02:07 PM Eastern Standard Time,
> > hol...@hotmail.com writes:
> >
> > A big issue with using the sawtooth correction message from a GPS
> > receivers is the issue of just what that sawtooth value is related to and
> > how to apply it to the measured PPS value / phase.
> > I added the ability to Lady Heather to calculate a sawtooth corrected
> > "paper clock" by applying the sawtooth correction message value to the PPS
> > output measured by an external counter like the TAPR TICC.
> >
> > There are around a dozen different combinations of sawtooth value and PPS
> > measurements...  only one of which minimizes the PPS error.  Do you add or
> > subtract the sawtooth value to the PPS measurement?  Do you apply the
> > sawtooth value to the previous/current/next PPS measurement?  Do you apply
> > the sawtooth correction to the PPS itself or the accumulated phase of the
> > PPS?
> > I don't think that I have ever seen what to do  with the sawtooth value
> > documented in any receiver documentation...  Heather has default receiver
> > dependent correction strategies or lets you specify the correction
> > strategy to use.___time-nuts
> > mailing list -- time-n...@lists.febo.comTo unsubscribe, go to
> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.comand follow
> > the instructions there.
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to
> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
> >
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Si5351A harmonics question

[Robert LaJeunesse]

Chris, better to set your SA to 5 MHz span with 2.5MHz center. Adjust the input 
attenuator (start with lots of attenuation)  until the 995 kHz peak is just 
less than the always present peak at zero frequency. (Namely always keep zero 
Hz at the left side of the screen, or to the left of that so it's off screen 
and you only display positive frequencies.)

I'd also consider adding to your (AC coupled) RF probe a series resistor of 450 
Ohms (470 in parallel with 10K is close enough) so as to not heavily load the 
'125. Yes, it attenuates by 20dB, but that's no problem for the SA. To be fair, 
a few pF cap across the resistors will flatten the frequency response at higher 
up. Use a 15pF trimmer and you can adjust it for a more accurate result.

Bob LaJeunesse

> Sent: Wednesday, June 05, 2019 at 11:33 AM
> From: "Chris Wilson" 
> To: "Discussion of precise time and frequency measurement" 
> 
> Subject: [time-nuts] Si5351A harmonics question
>
>
>
>   05/06/2019 16:24
>
> I am using a small transmitter called a U3S by QRP Labs as an exciter
> for a high power Class D amp. I take the output at circa 951kHz direct
> from CLK0 (it has no output stage built, I go direct from CLK0 on the
> Si5351A and input it to a level converter based on a SN74AHCT125N IC.
> The Class D amp needs a frequency input of X2 the desired output
> frequency. I have experienced terrible gate and drain waveforms on two
> Class d amps driven by this, so I put my SA on the output of the
> SN74AHCT125N via a switchable 50 Ohm attenuator. I see the trace in
> the first photo in the link below. Now I am the first to admit that
> apart from a fear of blowing the SA front end, I am a total novice
> with an SA. Are the high level additional frequencies away from the
> centre frequency to be expected, and do LPF's work on square waves? I
> di try a big high power 475 kHz LPF between the output of the
> SN74AHCT125N and the SA and the second shot was the result. Obviously
> that LPF is far from ideal though, but it was sat on the bench so I
> trie it Thanks please keep the answers at a novice level :)
>
> http://www.chriswilson.tv/mf.zip
>
> https://www.qrp-labs.com/ultimate3/u3s.html
>
> --
>Best Regards,
>Chris Wilson.
> mailto: ch...@chriswilson.tv
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Re; Motorola MC68HC11 Crystal

[Robert LaJeunesse]

Joe, I'm not Roger but I've worked a lot with Motorola micros. Your conclusion 
of 18pF seems reasonable as the design uses 24pF tuning caps, which are a bit 
high compared to the values recommended in the HC11 reference manuals. In 
section 2 they recommend 25pF total capacitance including strays, so I would 
not have used over 22pF caps to allow for tolerances. If I was going to switch 
from an 18pF crystal I'd consider a 15pF part on the assumption that stray 
capacitance is less than you allowed for. But 18 pf seems fine to me.

When measuring the oscillator be sure to use a high impedance low capacitance 
probe (<4pF) and only on the XTAL pin. Capacitively coupling that same probe to 
the EXTAL pin will give an idea how tolerant the oscillator is of additional 
loading. Note that Motorola recommended using only the E pin to determine 
oscillator frequency, it should run a 1/4 of oscillator frequency and be a very 
stable square wave. Jitter in E means you have a marginal oscillator. FWIW When 
looking at oscillator frequency it would be useful to break the line feeding 
C405 and bias that from an appropriate fixed supply.

Bob L.

> Sent: Thursday, March 07, 2019 at 1:41 AM
> From: "Joe Leikhim" 
> To: "Discussion of precise time and frequency measurement" 
> , j.r.tils...@runbox.com
> Subject: [time-nuts] Re;  Motorola MC68HC11 Crystal
>
> Roger, does the 18 pf load, crystal I have chosen for replacement seem
> correct for the design (attached)?
>
> Joe
>

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Loran-C Simulation

[Robert LaJeunesse]

FWIW there exists an online reference for SX BASIC at 
http://www.piclist.com/techref/parallax/sxb/sxb/___index.html which may prove 
helpful in understanding the SX-B code.

Unfortunately I can not find the SX-B BASIC compiler online anymore. 
http://www.parallax.com/sx/sxb.asp is 404.

Bob L.

> Sent: Tuesday, September 11, 2018 at 3:38 PM
> From: "gandalfg8--- via time-nuts" 
> To: time-nuts@lists.febo.com
> Cc: gandal...@aol.com
> Subject: [time-nuts] Loran-C Simulation
>
...
> Having said that, I did take a look at your Basic code and must admit is does 
> look pretty straightforward, even to me,
...
> 
> Nigel, GM8PZR

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] History Channel "In Search of" Time Travel

[Robert LaJeunesse]

I would appreciate it, thanks.

Bob LaJeunesse

> Sent: Saturday, August 18, 2018 at 3:22 PM
> From: "Dan Rae" 
> To: time-nuts@lists.febo.com
> Subject: Re: [time-nuts] History Channel "In Search of" Time Travel
>
> If anyone wants to see this I could upload a .mkv copy to Wetransfer for 
> download.
> Dan
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
> 

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] NIST

[Robert LaJeunesse]

I'd say it does get more detailed, with the $49M in cuts described generally in 
groups here:

https://www.nist.gov/director/fy-2019-presidential-budget-request-summary/fundamental-measurement-quantum-science-and

One item: "-$6.3 million supporting fundamental measurement dissemination, 
including the shutdown of NIST radio stations in Colorado and Hawaii"

Looks like some of your friends might be looking for work. Not good.

Bob L.


> Sent: Friday, August 10, 2018 at 3:11 PM
> From: "Magnus Danielson" 
> To: time-nuts@lists.febo.com
> Cc: mag...@rubidium.se
> Subject: Re: [time-nuts] NIST
>
> Bert,
> 
> The closes I come is this, burried in the line of Funamental Measurements:
> https://www.nist.gov/fy-2019-presidential-budget-request-summary/budget-tables
> 
> It doesn't get more detailed than that.
> 
> The T work is relatively small group in the big NIST.
> 
> Cheers,
> Magnus
> 
> On 08/10/2018 08:29 PM, ew via time-nuts wrote:
> >  
> > NIST total budget for 2017 was close to 965 Million, I was curios trying to 
> > find out what the Time and Frequency Division  portion was. No Luck. Does 
> > any one know?Thanks   Bert Kehren
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to 
> > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
> > 
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.