[time-nuts] Vintage Frequency Measurement

I was inspired recently coming across a Lampkin 105 frequency meter, as to how frequency measurement was done before counters. Certainly zero-beating a dial calibrated oscillator, would be one approach. Is there a standout methodology or instrument predating counters?

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

Hi Using ADEV as an example (the other stuff will have it’s own curves, but the result is the same): A typical Rb should have a stability at short tau that goes as 1/ square root(Tau). If you are at 2x10^-11 at 1 second, you will be at 2x10^-12 at 100 seconds and 2x10^-13 at 1,000 seconds.

Re: [time-nuts] Neoprene rubber drops GPS multipath signals to zero

On 2/11/17 10:22 AM, Poul-Henning Kamp wrote: In message <589f4a79.3050...@rogers.com>, MLewis writes: Late yesterday I placed old neoprene rubber mouse pads, rubber side outwards, up the metal blinds between the blinds and the antenna. I can guarantee you that it is not the

Re: [time-nuts] Neoprene rubber drops GPS multipath signals to zero

Hi For any microwave material, the good old “toss it in a microwave” test is a quick and dirty one. If the material heats up, it’s lossy. Yes, there are other fairly exciting things that can happen other than it warming a bit …. Bob > On Feb 11, 2017, at 5:51 PM, MLewis

Re: [time-nuts] Line Frequency standard change - Possible ?

In message <344e0d5f-e79f-fcfa-eba5-4cf50e047...@comcast.net>, Peter Reilley writes: >If a solar farm also included a battery bank then they would be able to supply >VAs along with Watts just like a conventional generator. The large MW size solar farms can already do that but with

Re: [time-nuts] Neoprene rubber drops GPS multipath signals to zero

Interesting. My guess wasn't a material made for RF but a carbon added to give a decent black colour. "It is not inconceiveable that off-spec or scrap materials from the production might end up as mousemats." and "stealth material". Very interesting. At an airshow many years ago, these

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

Thanks Bob, I should clarify the MTIE measurement extends 10 seconds (the others are less time). Is it a reasonable question to ask if GPS is needed? Or are there other variables that are involved? Good point about the temperature stability, I hadn't considered that. Can I place in a

Re: [time-nuts] Line Frequency standard change - Possible ?

In message <006a1c6a-0b2f-16fd-5fef-64352ff14...@earthlink.net>, jimlux writes: >On 2/9/17 4:03 PM, Poul-Henning Kamp wrote: >> >> In message <63beea7a-f9fc-6e1d-b855-2c7056de3...@earthlink.net>, jimlux >> writes: >> >>> I think also of the issues from distributed generation -

Re: [time-nuts] Line Frequency standard change - Possible ?

They may well be willing to pay for more expensive equipment because they can make money from it. large industrial electricity users pay for the VAs that they use. Even though they are not energy the utility has to supply them. The utility charges for this service. If a solar farm also

Re: [time-nuts] Line Frequency standard change - Possible ?

One issue with power factor corrected power supplies is that in the short term (as a minimum, at the line frequency), they do behave like resistors (current goes up when voltage goes up) but as they have a slow voltage regulation loop to provide regulated output, they do behave like constant power

Re: [time-nuts] Neoprene rubber drops GPS multipath signals to zero

In message <589f4a79.3050...@rogers.com>, MLewis writes: >Late yesterday I placed old neoprene rubber mouse pads, rubber side >outwards, up the metal blinds between the blinds and the antenna. I can guarantee you that it is not the neoprene itself which does it. It could be residual

[time-nuts] Neoprene rubber drops GPS multipath signals to zero

My TW4722 GNSS active antenna is on a 100 mm stainless ground-plane, placed on 2" of wood on a window sill behind two panes of glass, between metal blinds and the glass, almost touching the glass. Feeds a NEO-M8T. Late yesterday I placed old neoprene rubber mouse pads, rubber side outwards,

Re: [time-nuts] Line Frequency standard change - Possible ?

Hi, I know. In practice many of the operators in the US is working together to get smarter, share experiences and learn from each other and others. Good folks. Cheers, Magnus On 02/11/2017 04:08 PM, Bob Camp wrote: Hi To be fair to these guys, they have a number of challenges that have

[time-nuts] u-blox NEO-M8T GPS initial tracking test

I don't have an M8T, only an M8. Heather defaults to showing up to 14 satellites. You can specify more sats or a dual column display using the SI or GCT commands or you can click the mouse on the satellite info table. You can also use the SG command to set the GNSS configuration, but version

Re: [time-nuts] Line Frequency standard change - Possible ?

In message <9fd9beca-832a-4c38-9799-4a31625f7...@n1k.org>, Bob Camp writes: >Not an easy thing. Not even close, which is precisely why the "50/60 Hz or bust" mindset doesn't work any longer. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP

Re: [time-nuts] The USFS Frequency Standard...

In message <2126b261-3e4e-46d4-9181-1fb368244...@n1k.org>, Bob Camp writes: >One *could* make a WWVB “new modulation” receiver with some sort >of MCU demo board and a handful of parts. It would be fine for a basement >lab / learning sort of project. With reasonable OCXO as timebase, it

Re: [time-nuts] The USFS Frequency Standard...

Hi One *could* make a WWVB “new modulation” receiver with some sort of MCU demo board and a handful of parts. It would be fine for a basement lab / learning sort of project. Given the way the semiconductor world works, the longer you wait to start that project, the better a board you will have as

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

Hi Backing up a bit here. > On Feb 10, 2017, at 7:35 PM, gkk gb wrote: > > Hello experts, I need a Rubidium frequency reference for my company, and > wonder if I also need to GPS discipline it. > > > I characterize crystal-based OCXOs for ADEV, MTIE, and TDEV, and my

Re: [time-nuts] Line Frequency standard change - Possible ?

Hi To be fair to these guys, they have a number of challenges that have nothing to do with technology. They cross link to other companies and have little control over how each one operates. Here in the US, we have multiple regulatory agencies (it happens at the state, federal, and international

Re: [time-nuts] Line Frequency standard change - Possible ?

Work is already underway to improve the relicense of power grid operations. They is smarting up quickly. The PMU/synchrophasor measurements depend on UTC and before it can be used full-blown for operation the single point of failure needs to be handled. Cheers, Magnus On 02/09/2017 11:19 PM,

Re: [time-nuts] Line Frequency standard change - Possible ?

Hi Jim, On 02/09/2017 11:39 PM, jimlux wrote: On 2/9/17 1:31 PM, Poul-Henning Kamp wrote: In message <4fbdd81ddf04fc46870db1b9a747269202916...@mbx032-e1-va-8.exch032.ser verpod.net>, "Thomas D. Erb" writes: I was wondering if anyone was familiar with this proposal, is this a

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

From: gkk gb Hello experts, I need a Rubidium frequency reference for my company, and wonder if I also need to GPS discipline it. I characterize crystal-based OCXOs for ADEV, MTIE, and TDEV, and my longest measurement time is 100,000 seconds (28 hours). []

Re: [time-nuts] Line Frequency standard change - Possible ?

On Thu, 9 Feb 2017 17:19:49 -0500, you wrote: >Isn't this "hard" lock to UTC creating a single point of failure? A >solar burst, an EMP, or >a software error could leave us all in the dark. After all, smart >inverters could be >programmed to act like big lumps of rotating iron and be

Re: [time-nuts] Line Frequency standard change - Possible ?

On Thu, 9 Feb 2017 19:06:51 -0500, you wrote: >One simplistic way to look at all this is that a switcher presents a “negative >resistance” load. If you drop voltage, current goes up. OCXO’s happen >to share this issue. Negative resistances are *not* what most power source >guys want in their

Re: [time-nuts] Line Frequency standard change - Possible ?

On Thu, 09 Feb 2017 23:39:24 +, you wrote: >It is harder than it sounds. > >Small solar inverters are the best, they an regulate down at milliseconds >notice, and many jurisdictions impose asymetric frequency bands on >them to exploit this. > >Big inverters, no matter what you put behind