Re: [time-nuts] Cheap jitter measurements

It's worth noting that you can get rid of a /lot/ of the variance on a modern linux box: 1) Set the CPU to run at the same speed at all times (generally "max performance" but which way you do it doesn't really matter) 2) Set processor masks so that no processes other than your timing code

[time-nuts] Holdover: Z3801A vs KS-24361

On that Status page, A Z3801A says: Predict 2.5 us/initial 24 hrs A KS-24361 says: Predict 394.1 us/initial 24 hrs Both have been running for weeks. Is anybody seeing similar? Also, the Satellite Status area has a header of SS on the Z3801A and C/N on the KS. Does anybody know the

Re: [time-nuts] RINEX for Android

I think teqc.exe can read ubx-files directly Ole > 12. apr. 2018 kl. 12:46 skrev jimlux : > > It turns out that some of the newer Android phones support an API which > returns raw GNSS data and that can be logged to a file in RINEX format. > There's a few apps out there

Re: [time-nuts] RINEX for Android

At 05:46 AM 4/12/2018, jimlux wrote: It turns out that some of the newer Android phones support an API which returns raw GNSS data and that can be logged to a file in RINEX format. There's a few apps out there that do this although I've not tried it (my Samsung S6 doesn't have the right

Re: [time-nuts] Cheap jitter measurements

On Mon, Apr 9, 2018 at 3:36 AM, Tom Van Baak wrote: > > My mental model of a black box computer running NTP is that I should be able > to give it a pulse (e.g., via parallel, serial, GPIO) and it tells me what > time it was. Use a GPSDO / Rb / picDIV to generate precise

[time-nuts] RINEX for Android

It turns out that some of the newer Android phones support an API which returns raw GNSS data and that can be logged to a file in RINEX format. There's a few apps out there that do this although I've not tried it (my Samsung S6 doesn't have the right hardware). In any case, it might be

Re: [time-nuts] Holdover: Z3801A vs KS-24361

Hi > On Apr 12, 2018, at 1:30 AM, Hal Murray wrote: > > On that Status page, A Z3801A says: > Predict 2.5 us/initial 24 hrs That sounds about right for a 3801. The prediction is something better than a wild guess and not what one would call a solid number. > > A

Re: [time-nuts] RINEX for Android

On 4/12/18 6:57 AM, Ole Petter Rønningen wrote: I think teqc.exe can read ubx-files directly Ole 12. apr. 2018 kl. 12:46 skrev jimlux : It turns out that some of the newer Android phones support an API which returns raw GNSS data and that can be logged to a file in

[time-nuts] Holdover: Z3801A vs KS-24361

SS is signal strength. CN is carrier to noise ratio. They basically indicate the same thing, but their scale may be different. You can't compare the absolute magnitude of the values from different types of receivers, only do relative comparisons. Other receivers can report dBc, etc.

Re: [time-nuts] RINEX for Android

Hi Jim, Teqc is not a Windows-only program. There are actually several ARM/Debian compilations. I assume some receiver protocols have been implemented with NDAs attached (hey Trimble...) and that might be one reason not to distribute source code. However if JPL would have a long term need for

Re: [time-nuts] TCVCXO Adjustment

On Tue, April 10, 2018 6:10 pm, Wayne Holder wrote: > which is spec'd at a frequency tolerance or +/- 1 PPM and a frequency > stability of 0.28 PPM and a yearly aging of +/- 1 PPM max/year which, to > me, seems pretty impressive for a part that costs about $8. Something like this MEMS oscillator

Re: [time-nuts] RINEX for Android

Hello Jim, There's a Perl script here https://github.com/openttp/openttp/blob/develop/software/gpscv/ublox/ubloxlog.pl that's for configuring and logging a ublox NEO-8MT. The caveat is that it uses a custom file format. However, the associated processing software, mktimetx, will read this and

Re: [time-nuts] TCVCXO Adjustment

On Tue, April 10, 2018 8:12 pm, Bob kb8tq wrote: > Since your typical PC does not have anything in it that is accurate to 0.1 > ppm, you still need something as a reference to compare things to. > A GPS module or a GPSDO are probably the easiest things to get ahold of. Catching up on some of the

Re: [time-nuts] TCVCXO Adjustment

First, thanks for all the comments and suggestions, It's given me a lot to think about and research. Based on the feedback I've received, I've started to investigate using the NTP server approach suggested by Chris Caudle. I also found this NIST Paper

Re: [time-nuts] TCVCXO Adjustment

Why not put a GPS receiver in it ? It won't always get a lock, but if it gets accurate time every few weeks it can do the long-term tweaking someone suggested in the watch thread (call in to the watch repair two weeks apart). Except it can be done more or less EVERY two weeks. I agree, a phone

Re: [time-nuts] Dual GPSDO - any advantage?

FYI eBay pulled the listing and they bounced the seller. Spent 15 minutes on the phone with eBay and they canceled the purchase with an immediate refund. You'll probably need to call since with no listing and no seller, it's nigh impossible to use the normal resolution methods. Paul On

Re: [time-nuts] WWVB information

Hi, Doug, How is your 8161 doing now? Still synced properly? Should I bring my 8164 up from the basement? I was so disappointed when WWVB changed their modulation. Thanks for any encouragement. 73, ... MartinVE3OAT On Wed, 11 Apr 2018 16:28:41 Doug Millar wrote : > Hi, My Spectracom

[time-nuts] RINEX for Android

Lady Heather will write raw data capture files from any of the devices that it supports. It can also read them in as a simulation file (except for "polled" receivers where you have to explicitly poll the receivers for each piece of data you want... the polling queries are not written to the

Re: [time-nuts] WWVB information

I've been talking with Doug to better understand why his Spectracom WWVB receiver shows the green lock indicator. This receiver should not work given the enhanced WWVB modulation we've had since 2012. Fortunately he has chosen not to touch anything while we ponder this. Meanwhile I pulled out

Re: [time-nuts] RINEX for Android

On 4/12/18 1:29 PM, Björn wrote: Hi Jim, Teqc is not a Windows-only program. There are actually several ARM/Debian compilations. I assume some receiver protocols have been implemented with NDAs attached (hey Trimble...) and that might be one reason not to distribute source code. However if

Re: [time-nuts] Weird Stuff Warehouse shutting down

I was at Weird Stuffabout a month ago. Picked up a heavy microscope base. Those are the things you really don't want to buy on ebay. To be honest, I wasn't finding much there. My dentist is nearby, and that was when I would check them out. How old is the stuff on their racks? Remember Bay