Re: [time-nuts] Raspberry Pi TCXO Hat

David J Taylor via time-nuts writes: > The graph in ntpviz shows the jitter and temp almost perfectly correlated. Based on my experience it should really be a correlation of temperature rate of change vs. jitter. On my self-ovenized servers I see on average around 200ns jitter (close to the

Re: [time-nuts] Raspberry Pi TCXO Hat

From: shouldbe q931 Have you considered driving multiple Pi from the same PPS source ? And to keep their temperature stable, keeping all three in the same enclosure ? Cheers Arne == Yes, that would be an interesting experiment, Arne, but I don't have the

Re: [time-nuts] Raspberry Pi TCXO Hat

On Tue, Nov 5, 2019 at 12:03 PM David J Taylor via time-nuts wrote: > > Folks, > > As a matter of interest, I've just compared the reported jitter on a RPi 3B, > RPi 3B+ and RPi-4B, all PPS synced with classic NTP, all in the same room, > but with slightly different puck antenna locations. Have

Re: [time-nuts] Raspberry Pi TCXO Hat

From: Richard Laager On 11/2/19 1:15 AM, Hal Murray wrote: rlaa...@wiktel.com said: I'm curious if this would provide any meaningful improvement in system clock accuracy, for NTP, if I'm already a GPS PPS hat. If there's a reasonable chance this could be interesting, I'm thinking about

Re: [time-nuts] Raspberry Pi TCXO Hat

Richard Laager writes: > How would it work to have two crystals connected in parallel? Not two crystals in parallel, a crystal plus the output of an (external) reference oscillator. If the two frequencies are close enough you can injection lock the crystal oscillator, but the more likely outcome

Re: [time-nuts] Raspberry Pi TCXO Hat

> The graph in ntpviz shows the jitter and temp almost perfectly correlated. I'd expect drift to be tracking temperature much better than jitter. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To

Re: [time-nuts] Raspberry Pi TCXO Hat

On 11/2/19 1:15 AM, Hal Murray wrote: > > rlaa...@wiktel.com said: >> I'm curious if this would provide any meaningful improvement in system clock >> accuracy, for NTP, if I'm already a GPS PPS hat. If there's a reasonable >> chance this could be interesting, I'm thinking about ordering a couple

Re: [time-nuts] Raspberry Pi TCXO Hat

On Sat, November 2, 2019 6:37 am, Adrian Godwin wrote: > Also - I'm unsure of the benefit of having a TCXO for the ethernet clock Would only be of benefit if using an Ethernet device which timestamps IEEE 1588 packets with the clock running in the NIC. Typical usage on a linux based system

Re: [time-nuts] Raspberry Pi TCXO Hat

Hi Congratulations !!! You have just invented Sync-E. Seems like *maybe* somebody beat you to it …. https://en.wikipedia.org/wiki/Synchronous_Ethernet Turns out it is one way to get *frequency* to a device (like a cell site). Just how well

Re: [time-nuts] Raspberry Pi TCXO Hat

Richard Laager writes: > I stumbled across this product listing: > https://www.teradak.com/products/115.html That site red-zones my BS detector… > It's a Pi hat that contains two TCXOs, one at 19.2 MHz for the CPU and > one at 25 MHz for the Ethernet controller. The one for the Ethernet

Re: [time-nuts] Raspberry Pi TCXO Hat

artgod...@gmail.com said: > Also - I'm unsure of the benefit of having a TCXO for the ethernet clock > unless it runs so hot that ethernet can't sync using the usual uncompensated > crystal. Is there some benefit I'm not seeing ? I had similar thoughts. One could imagine using Ethernet to

Re: [time-nuts] Raspberry Pi TCXO Hat

The Pi 4 launched with issues, including heat issues, but has been improved. The improvements in power usage are supposed to reduce the heat issues. A new bootloader was released. It includes that by default, power will be maintained on the power pins, so power is maintained on hats.

Re: [time-nuts] Raspberry Pi TCXO Hat

Also - I'm unsure of the benefit of having a TCXO for the ethernet clock unless it runs so hot that ethernet can't sync using the usual uncompensated crystal. Is there some benefit I'm not seeing ? On Sat, Nov 2, 2019 at 12:35 PM Adrian Godwin wrote: > > > On Sat, Nov 2, 2019 at 11:59 AM David

Re: [time-nuts] Raspberry Pi TCXO Hat

On Sat, Nov 2, 2019 at 11:59 AM David J Taylor via time-nuts < time-nuts@lists.febo.com> wrote: > > Given that the path to the outside Ethernet world on both of those models > is > via a USB controller, I would expect to see very little improvement with a > TCXO in a constant temperature

Re: [time-nuts] Raspberry Pi TCXO Hat

rlaa...@wiktel.com said: > I'm curious if this would provide any meaningful improvement in system clock > accuracy, for NTP, if I'm already a GPS PPS hat. If there's a reasonable > chance this could be interesting, I'm thinking about ordering a couple and > "sacrificing" a Pi 3 and/or Pi 4.

Re: [time-nuts] Raspberry Pi TCXO Hat

I stumbled across this product listing: https://www.teradak.com/products/115.html It's a Pi hat that contains two TCXOs, one at 19.2 MHz for the CPU and one at 25 MHz for the Ethernet controller. It's a rather permanent modification, as you have to desolder the stock crystals and replace them

[time-nuts] Raspberry Pi TCXO Hat

I stumbled across this product listing: https://www.teradak.com/products/115.html It's a Pi hat that contains two TCXOs, one at 19.2 MHz for the CPU and one at 25 MHz for the Ethernet controller. It's a rather permanent modification, as you have to desolder the stock crystals and replace them