Re: [time-nuts] Using lasers for data transmission

On 1 May 2016 15:02, "Bruce Griffiths" wrote: > > The solution with high power is to use a beam expander so that the unaided eye cannot collect a power greater than the safe limit. Using near IR beams also helps. > Bruce It is a long time since I worked with lasers,

Re: [time-nuts] help

> But are you sure you want SMPTE... Do you have a source already? > > You don't need GPS or SMPTE if you have an Internet connection. The computer can use a set of NTP servers from the "pool" to get time. The result is good enough that the seed of sound delay resulting from your random distance

Re: [time-nuts] help

On Sun, May 1, 2016 at 12:26 PM, Bill Baker via time-nuts < time-nuts@febo.com> wrote: > My problem: I'd like some kind of off-the-shelf device that can take the > time code and switch on or impulse another circuit-- specifically I'd like > to trigger a 180 year-old fog bell (I'm a lighthouse

[time-nuts] Original Oncores for free

Does anyone want two non-working 6-channel Oncores that I pulled from Z3801A's? They may be repairable, but now that I have working VP's and spares, I don't want to take the time to fool with them. Just thought I'd ask before tossing them in the recycle bin. Joe Gray W5JG

Re: [time-nuts] help

On 5/1/16 1:26 PM, jimlux wrote: On 5/1/16 12:26 PM, Bill Baker via time-nuts wrote: My problem: I'd like some kind of off-the-shelf device that can take the time code and switch on or impulse another circuit-- specifically I'd like to trigger a 180 year-old fog bell (I'm a lighthouse nut as

Re: [time-nuts] synchronization for telescopes

Attila, I don't think a cheap receiver like a LEAxxx will quite get you there. On Mon, May 2, 2016 at 1:10 AM, Attila Kinali wrote: > Moin, > > Let's quickly recap what the requirements are and what has been discussed > so far: > > What I think has the best chances of success

Re: [time-nuts] Fw: Optical transfer of time and frequency

Javier, On 05/01/2016 02:54 PM, Javier Serrano wrote: On Sun, May 1, 2016 at 9:50 AM, Magnus Danielson wrote: If I recall correctly, there where some White Rabbit stuff available from vendors, was it only Ethernet switches or also cards? Yes, the switch is

Re: [time-nuts] help

On 5/1/16 12:26 PM, Bill Baker via time-nuts wrote: My problem: I'd like some kind of off-the-shelf device that can take the time code and switch on or impulse another circuit-- specifically I'd like to trigger a 180 year-old fog bell (I'm a lighthouse nut as well, www.henryisland.com) on

[time-nuts] help

My problem: I'd like some kind of off-the-shelf device that can take the time code and switch on or impulse another circuit-- specifically I'd like to trigger a 180 year-old fog bell (I'm a lighthouse nut as well, www.henryisland.com) on the hour and maybe be able to impulse my minute school

Re: [time-nuts] Using lasers for data transmission

Thank you, I personally were talking about 1400nm 1mw lasers, however. Supplying just above the threshold current is not a problem. does the raising time can be reduced if using lower current/voltage raises or falls? I mean: how's calculated the raise time, full-scale pulse or for a mW/mA or

Re: [time-nuts] Using lasers for data transmission

On 5/1/16 9:48 AM, Mark Sims wrote: There are "eye-safe" wavelengths that some laser diodes can operate at (generally greater than 1300 nm). These are much less prone to damage eyes. Basically your eyeball juice blocks the wavelength. Still, there is some potential for cornea and lens

Re: [time-nuts] Fw: Optical transfer of time and frequency

On Sun, May 1, 2016 at 5:44 PM, Tom Van Baak wrote: > This particular issue -- how to synchronize (or, at least phase compare) > multiple oscillators by a two-way laser link over a few km to within 500 ps > -- is really quite interesting. It would, for example, allow me to

[time-nuts] Using lasers for data transmission

Also, a lot of laser diodes don't like to be "cold-started". Your modulation scheme needs the laser to always be on at some minimum level above Ith. Just crudely switching from off to on can quickly kill the diode.

[time-nuts] Using lasers for data transmission

There are "eye-safe" wavelengths that some laser diodes can operate at (generally greater than 1300 nm). These are much less prone to damage eyes. Basically your eyeball juice blocks the wavelength. Still, there is some potential for cornea and lens damage at higher powers.

[time-nuts] My TS-2100 Started Working Today???

Hey Guys, sorry I've been MIA for a while. Things happened, moved 500+ miles, etc, etc... I haven't had some of my time servers on in years, including my TS-2100. Yesterday I was running some Ethernet cable in my house and also mounted a GPS antenna up in the attic. Fired up a few time servers,

Re: [time-nuts] Fw: Optical transfer of time and frequency

> Has anybody experienced with free-space optical gigabit Ethernet > links? I am curious about whether the transceivers have a fixed > latency or at least a latency one can easily quantify online. This is > the trickiest part for adding WR support on top of a given physical > layer. Hi Javier,

[time-nuts] synchronization for telescopes

Moin, Let's quickly recap what the requirements are and what has been discussed so far: 1) Time sync system of two (multiple?) sites spaced around 2km to better than 1ns, preferably 100ps. 2) System has to be mobile, no fixed installation 3) No amateur radio license available 4) Total cost

Re: [time-nuts] Fw: Optical transfer of time and frequency

On Sun, May 1, 2016 at 9:50 AM, Magnus Danielson wrote: > If I recall correctly, there where some White Rabbit stuff available from > vendors, was it only Ethernet switches or also cards? Yes, the switch is available from two vendors that I know of. They are

Re: [time-nuts] Using lasers for data transmission

On 5/1/16 3:22 AM, Bruce Griffiths wrote: The solution with high power is to use a beam expander so that the unaided eye cannot collect a power greater than the safe limit. Using near IR beams also helps. Bruce IR is a problem for eye safety, because IR doesn't trigger the blink reflex, so

Re: [time-nuts] Using lasers for data transmission

Dear Ilia On Sun, May 1, 2016 at 6:40 PM, Ilia Platone wrote: > The problem would be modulating a 10GBASE-T signals into a single laser > beam, and demodulating it using (I think) an APD. > The White Rabbit cards use SFP (small form-factor pluggable) lasers that plug into

Re: [time-nuts] Misc topics

I got a large reply to give the 8662 away, let the old/new one arrive and be ok, and the first one who contacted me will get mine. Good luck with the repair of the power supply. The 8662 works correct occasionally, starts up and then not but is in specs. I will be in San Francisco IMS /MTT

Re: [time-nuts] Using lasers for data transmission

The solution with high power is to use a beam expander so that the unaided eye cannot collect a power greater than the safe limit. Using near IR beams also helps. Bruce On Sunday, 1 May 2016 9:00 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: >

Re: [time-nuts] Using lasers for data transmission

Threshold current should not be a problem because if there's no data the laser could go into "power saving mode". As am modulation a simple buffer/r2r network DAC should do the job. The signals to transmit are three: Tx, and two bidirectional. Ilia. Il 01/05/2016 10:27, Dr. David Kirkby

Re: [time-nuts] Using lasers for data transmission

> Hi, > Several (many?) years ago National Geographic magazine show a picture taken here in southern California of the state government sending red laser signals between different mountain tops to keep track what was going on near fault lines > There were no technical details on what was taking

Re: [time-nuts] Using lasers for data transmission

The problem would be modulating a 10GBASE-T signals into a single laser beam, and demodulating it using (I think) an APD. except the one depending on light travel, that shouldn't be a problem if using White Rabbit, there could be some problem with the modulating and transmitter/receiver delay

Re: [time-nuts] Z3801A recovering

After about three hours: https://dl.dropboxusercontent.com/u/19599147/Z3801A%203hr.png Ignore the graph discontinuity at the beginning. I had to power cycle to change to UTC. Joe Gray W5JG On Sun, May 1, 2016 at 1:30 AM, Joseph Gray wrote: > In past discussions about

Re: [time-nuts] Z3801A recovering

In past discussions about replacing a 6-channel Oncore in a Z3801A with an 8-channel VP Oncore, some claimed that the VP had to first be put into 6-channel mode, others indicated this was not necessary. Earlier tonight, I put a VP (still in 8-channel mode) into my malfunctioning Z3801A. Monitoring

Re: [time-nuts] Fw: Optical transfer of time and frequency

Javier, If I recall correctly, there where some White Rabbit stuff available from vendors, was it only Ethernet switches or also cards? Cheers, Magnus On 05/01/2016 01:14 AM, Bruce Griffiths wrote: On Sunday, 1 May 2016 10:52 AM, Bruce Griffiths wrote:

[time-nuts] Using lasers for data transmission

Hi, Several (many?) years ago National Geographic magazine show a picture taken here in southern California of the state government sending red laser signals between different mountain tops to keep track what was going on near fault lines. There were no technical details on what was taking