[time-nuts] GPS altitude somewhat wrong?

I have just installed a Thunderbolt here to get our time and frequency equipment all on the same page. As I was looking at the display on Lady Heather, I was noticing that the GPS altitude seems rather wrong. We are in Boulder CO, which is nominally 5430' and the antenna is about 20' off the

Re: [time-nuts] GPS altitude somewhat wrong?

Some of that is probably the difference between the geoid (what your surveyed maps report height relative to) and the WGS84 ellipsoid (what your GPS reports heights relative to). At Boulder that difference is only about 15 meters, though. Generally with VDOP < 2 and a reasonably modern

Re: [time-nuts] GPS altitude somewhat wrong?

Using the thunderbolt here. I only asked because a co-worker spotted the altitude and thought it was "wrong" for boulder. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims Sent: Thursday, June 9, 2016 10:56 AM To: time-nuts@febo.com Subject:

Re: [time-nuts] GPS altitude somewhat wrong?

0'. Ok.. Michael Perrett On Wed, Jun 8, 2016 at 1:33 PM, Van Horn, David < david.vanh...@backcountryaccess.com> wrote: > > I have just installed a Thunderbolt here to get our time and frequency > equipment all on the same page. > As I was looking at the display on Lady Heather, I

Re: [time-nuts] GPS altitude somewhat wrong?

, Van Horn, David < david.vanh...@backcountryaccess.com> wrote: > > I have just installed a Thunderbolt here to get our time and frequency > equipment all on the same page. > As I was looking at the display on Lady Heather, I was noticing that > the GPS altitude see

Re: [time-nuts] Mains Frequency Monitor with the PIC 16F1619 (Daniel Watson)

Amusing story: Back in high school, Ewa Beach Hawaii, I used to notice that the second hand on the clocks would sometimes slow significantly. This turned out to be caused by the man who would later become my father in law. He ran the steel mill, melting old cars into rebar, which was

Re: [time-nuts] HP5370 power supply measurements

Have you tried a 110V shaded pole motor fan? Only 60Hz magnetic noise, no brushless commutation or brushes. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims Sent: Wednesday, July 13, 2016 9:50 AM To: time-nuts@febo.com Subject: [time-nuts]

Re: [time-nuts] OXCO Spurious Output at Line Frequencies

Perhaps the aliens are replying to our signals, mostly saying "SHUT UP!!!" -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Wednesday, July 13, 2016 2:18 AM To: Discussion of precise time and frequency measurement; Bob Camp

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

p...@heypete.com said: > I'm a little concerned about the speed at which the pulses need to be > counted. The 32kHz pulses come in every ~30.5 microseconds, and handling an > interrupt on an ATmega328 running at 16MHz takes about 5.125 microseconds[1] Huh? Instruction cycle time is 62.5nS for

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

O M G.. So I followed the link and saw how they do it.Wow. They write interrupts like the DMV processes applications. I can only imagine what this looks like on the PIC, where every instruction takes 4x as many cycles. All of that pushing and popping is PRECISELY what you need to avoid.

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

>That all assumes you have turned interrupts off for some reason. Common >reasons could be that you are in another interrupt service routine or that >you are executing interrupt related code. > >Bob What I saw in their interrupt routine was a "full boat" implementation, pretty typical for

Re: [time-nuts] Nutty time-nuttery with WWVB

I have, for many years, wished the FCC would get serious on enforcement. I've dealt with CEOs who said basically "ok, so it's illegal, who's going to catch us?" I have on occasion had to physically stop shipments from being made. If we had enforcement with TEETH then it would be easy to make

Re: [time-nuts] Nutty time-nuttery with WWVB

Enforcement.. It would be nice. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Alex Pummer Sent: Thursday, November 10, 2016 10:39 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Nutty time-nuttery with WWVB And

Re: [time-nuts] Temp/Humidity control systems

There is a wax which melts at 70F. Phase change stores and releases a lot of heat. Somewhat optimistic IMHO https://www.wired.com/2015/05/table-sucks-heat-lower-ac-bills/ http://www.stacoolvest.com/news/ Technical: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4809117/

Re: [time-nuts] For those that insist on using switching power supplies

To be fair here, phone chargers have almost no requirement to be quiet other than conducted and radiated emissions limits. It's charging a battery. As a designer of some fairly quiet SMPS systems, this feels like "look how bad a family car this tractor is".

Re: [time-nuts] Totally unrelated, but..

) Testing stops the oscillation Bob > On Dec 6, 2016, at 4:24 PM, Van Horn, David > <david.vanh...@backcountryaccess.com> wrote: > > Lots of discussion on here about low noise regulation so someone may know > what to look for. > > I have a receiver which is getting

Re: [time-nuts] Totally unrelated, but..

The probes don't seem to affect anything. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Andy Sent: Wednesday, December 7, 2016 7:56 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Totally unrelated, but.. > > I

Re: [time-nuts] Totally unrelated, but..

Yes, I hit one of those. I forget the frequency other than around 1 MHz, but it was pretty warm when it shouldn't have been, and it was several volts amplitude. This thing I'm chasing is much more subtle. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf

Re: [time-nuts] Totally unrelated, but..

I did check the circuit through the whole range that it should operate in, based on component data sheets. No issues. I also carefully varied the voltage right around where the regulator output is, to see if there was some very narrow band of sensitivity. Nothing. -Original Message-

Re: [time-nuts] Totally unrelated, but..

> regulator in an odd way. > 2) The oscillation / noise is at a very low level and it’s below your > test gear’s noise floor > 3) Testing stops the oscillation > > Bob > > > On Dec 6, 2016, at 4:24 PM, Van Horn, David <david.vanhorn@ > backcountryaccess.com> wrote: > >

Re: [time-nuts] Totally unrelated, but..

Possible, but it should not need that, and the original design didn't include it. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Wednesday, December 7, 2016 10:35 PM To: Discussion of precise time and frequency measurement Cc:

[time-nuts] Totally unrelated, but..

Lots of discussion on here about low noise regulation so someone may know what to look for. I have a receiver which is getting a lot of interference from somewhere. Antenna disconnected, interference still high. After much poking around, we found that replacing a voltage regulator with a

Re: [time-nuts] UCCM GPSDO

Yes. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Glen Hoag Sent: Monday, December 5, 2016 12:14 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] UCCM GPSDO 94V-0 is a UL flame retardancy test, if I recall

Re: [time-nuts] Line Voltage - USA

I once had some odd equipment failures which we found out were caused by the line voltage being at 142V. This was in the mid 80's in Costa Mesa CA. The tech they sent out told me they had us on the wrong transformer tap. Lowest I've seen was 70V in Hawaii, with everyone coming home about 5PM

Re: [time-nuts] Line Voltage - USA

the damaged equipment? On Tue, Jan 3, 2017 at 9:33 PM Van Horn, David < david.vanh...@backcountryaccess.com> wrote: > I once had some odd equipment failures which we found out were caused > by the line voltage being at 142V. > > This was in the mid 80's in Costa Mesa CA. The

Re: [time-nuts] Bye-Bye Crystals

In my design I need 10ppM, and then I divide by 8. Software can't correct for anything. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Bownes Sent: Tuesday, March 14, 2017 10:50 AM To: Discussion of precise time and frequency measurement Subject:

Re: [time-nuts] Bye-Bye Crystals

Probably true for many things. My current design has six crystals, and exactly none of them could be replaced by an oscillator module. Power and space considerations mostly. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] Trimble Thunderbolt no longer determines the correct date

Hmm.. Just a while ago, I watched the heather display on ours go to 12:59:59 and stop... Still giving me 10 MHz though which is all I really need. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] TAPR Oncore M12+ kit

Milling internally and externally to the perimeter of the board is a price adder, but is routinely done and not expensive. I've done round PCBs with large, oddly shaped "round" holes in the middle, impossible to drill. I've done PCBs where the outer corners had to be milled to a specific

Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse

There's an excellent article out there on the web called "Low Voltage, the incompetent ignition source" I highly recommend a read. I dealt with a case like this a couple years ago. Failed fet in an H bridge caused a fault which the brick SMPS picked up as a short, and went into "hiccup" mode

Re: [time-nuts] HP10811 Oscillator Thermal Fuse

-- Forwarded message -- From: Van Horn, David <david.vanh...@backcountryaccess.com> Date: Thu, May 11, 2017 at 4:31 PM Subject: Re: [time-nuts] Fwd: HP10811 Oscillator Thermal Fuse To: Discussion of precise time and frequency measurement <time-nuts@febo.com> There's an excellent

Re: [time-nuts] How to love your Power Poles.

One thing I love about them is that you can create odd geometries. All my ham gear, and generally anything I own that's 12V has APPs in the OC Races standard. All lead acid sources are also same. I could see using a different geometry for lithium batteries and the stuff that goes with them, and

Re: [time-nuts] Power connectors continued

I have a design rule that I've used for decades: "If it fits, it works, or it does no harm." -Original Message- Why so many connecter types? So you don't cross stuff up. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go

Re: [time-nuts] Machining some aluminum help!

For popping off the lid, a few threaded holes in the lid would be nice. Insert screws and let them push against the body and push the lid off. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of ed breya Sent: Thursday, May 25, 2017 3:08 PM To:

Re: [time-nuts] Poor man's oven

You can feed in an external AREF, but look at the data sheet for the particular AVR chip. One thing which is commonly ignored in Arduino-Land is the I/O pin leakage current and the maximum source impedance specs. You are well advised to buffer the voltage you are reading, or make sure the

Re: [time-nuts] backfill (was: Poor man's oven)

Wouldn't the low density of helium reduce some mechanical friction? I realize the motions are small but they are motions. The "Cousteau effect"? :) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] External cooling fans - source

In the US, I have seen line voltage as low as 70VAC and as high as 145VAC. That's what I design to. The power companies say different, but my meters don't lie. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Jeremy Nichols Sent: Tuesday, December 19,

Re: [time-nuts] Anybody have suggestions for time related science fair projects?

What I remember was a brown or black disc with holes around the perimeter. I remember a lot of holes. This was around 1991 or so. -Original Message- From: time-nuts On Behalf Of Bruce Griffiths Sent: Saturday, May 12, 2018 4:39 PM To: Discussion of precise

Re: [time-nuts] Anybody have suggestions for time related science fair projects?

Ah. The falling water goes up illusion. https://www.youtube.com/watch?v=GBtHeR-hY9Y -Original Message- From: time-nuts On Behalf Of ed breya Sent: Monday, May 14, 2018 2:01 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Anybody have suggestions for time

Re: [time-nuts] GPS Timing Antenna Failure - Long

There's a great article out there on the web. It takes a bit of digging, but the title is "Low voltage, the incompetent ignition source". They discuss fires on PCBs caused by trace contaminants and dendrite growth. A PCB with sustained flame is shown, powered by a lithium coin cell.

Re: [time-nuts] Anybody have suggestions for time related science fair projects?

Measuring the speed of light (Fizeau or Michelson method? Other ways) I saw a great demo of this at the Exploratorium in SF. They had a long spool of fiber optic, a disc with holes, and a light source. When static, if the light shines through the hole in the disc into the fiber, then you

Re: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

Nicads are still made. NIMH is not necessarily a drop in. While it will work fine in the short term, crude chargers that implement constant trickle like C/10 can be (emphasis) tolerated (/emphasis) by some NIMH cells, and totally out of spec for others. Modern chargers and NIMH is a good

Re: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

In a former job I designed battery charging systems for NIMH cells. Some cells will TOLERATE long term trickle, some spec ZERO trickle current. Get a data sheet and read it. Violating that spec, or low quality cells can get you a battery pack that will arbitrarily, and without even being

Re: [time-nuts] HP 105B: Modern replacement for NiCad battery pack?

Memory... :) I've induced the "memory effect" in NIMH cells and Nicad, and lead acid. Simply charge to the same point, then discharge to the same depth of discharge about 10x. In the next cycle, discharge completely and you'll see the bump in pack voltage where you had discharged to

Re: [time-nuts] Anyone have experience with this antenna?

In a previous job, I used plastics to "lens" antennas at 2.4 GHz, shaping the patterns for more desirable results. XFDTD is a great software package for this application but it is expensive. ___ time-nuts mailing list -- time-nuts@febo.com To

Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

specs they are given. You want cheap crap, they'll build cheap crap. You want top quality, they'll build top quality. On Thursday, February 22, 2018, Van Horn, David < david.vanh...@backcountryaccess.com> wrote: > According to the data sheet, it looks pretty well in spec, and the >

Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

According to the data sheet, it looks pretty well in spec, and the part has thermal shutdown. http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf ESD hit maybe? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

"Some  of you are to young to remember when Javanese products were considered junk same storyBert Kehren" I've lived through Japan, Taiwan, and now China. Who's next?  ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] Terrestrial GPS

I've seen wifi location reporting me almost 2000 miles east of where I am. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.