[time-nuts] Re: Query about List and about 10 MHz Distro

[Dana Whitlow]

Bob,

In my case simply disconnecting the long interconnecting cables at both
ends almost
completely eliminated the problem.  Hence my expectation that use of fiber
optics
would be effective.

Dana


On Sat, Aug 28, 2021 at 7:27 PM Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
> Anything you do that has a bunch of 10 MHz cables running out from here or
> there
> will impact your ability to listen to WWV at 10 MHz :)  Other than killing
> all the sources,
> there is no silver bullet.
>
> Bob
>
> > On Aug 28, 2021, at 7:57 PM, Dana Whitlow <k8yumdoober at gmail.com> wrote:
> >
> > Bob, my own motivation  for going to fiber was entirely different.  I
> > simply wanted to
> > run 10 MHz all over the place from reference sources in disparate
> > locations in the
> > house, and I quickly discovered that cable leakage was embarrassingly
> > severe.  So
> > I shut down and began contemplating a fiber link.  But then reality set
> in
> > and I realized
> > that running fiber across the house had its own big problems, so I set
> the
> > project aside.
> >
> > Dana
> >
> >
> > On Sat, Aug 28, 2021 at 3:32 PM Bob kb8tq <kb8tq at n1k.org> wrote:
> >
> >> Hi
> >>
> >> With a whole variety of pretty good OCXO’s going for cheap money
> >> on eBay, it’s likely less expensive to do cleanup oscillators on the
> link
> >> compared to going crazy with low noise optical this or that. Yes, you
> >> will be getting something in the high 150’s for noise, but still pretty
> >> good
> >> for $10.
> >>
> >> If you need better, spend $50 or so on a 10811. Still less money than
> >> some of the crazy fiber stuff.
> >>
> >> With either one, send over a high enough frequency that the loop isn’t
> >> dealing with reference spurs in any significant way. Given the clock
> rates
> >> Ethernet runs at these days, that part should be fairly straightforward.
> >>
> >> This *assumes* that there is a crossover somewhere practical between
> >> the fiber noise and the noise on the optical gear. You should be able to
> >> work out what it is with some fairly normal phase noise or ADEV testing.
> >>
> >> Bob
> >>
> >>> On Aug 28, 2021, at 3:03 PM, Dana Whitlow <k8yumdoober at gmail.com>
> wrote:
> >>>
> >>> I was looking for something similar about 18 months or so ago.
> Although
> >> I
> >>> haven't taken any
> >>> action yet, I concluded that one could do a nice job for under $200 per
> >>> segment, including the
> >>> transmitter and receiver modules and lots of connectorized multimode
> >>> fiber.  What I *don't* know
> >>> is what the phase noise performance would be, except that I do know
> that
> >>> the fiber's VF *is*
> >>> materially influenced by temperature.
> >>>
> >>> I was looking primarily at the HFBR-2416 for the fiber receiver, and
> the
> >>> HFBR-1412 (standard
> >>> power) or the HFBR-1414 (high power option) for the transmitter
>  Unlike
> >>> most of the available
> >>> models, these are fundamentally analog devices, meaning that you can
> >>> transmit sinewave
> >>> 10 MHz through them.  At the time I was looking, Mouser was selling
> these
> >>> for about $20 each.
> >>>
> >>> See the datasheet at
> >>>
> >>
> https://www.mouser.com/datasheet/2/678/AV02-0176EN_2019-02-15-1827546.pdf
> >>> with particular attention to page 21 regarding the HFBR-2416 receiver.
> >>>
> >>> I was also looking at Fiber Instrument Sales for patch cords.  We
> bought
> >> a
> >>> lot of fiber stuff from
> >>> them at Arecibo, and I was always happy with them.  See:
> >>>
> >>
> https://www.fiberinstrumentsales.com/catalog-cable-assemblies?gclid=Cj0KCQjwvaeJBhCvARIsABgTDM7eNTkP2nQbyFzhcwDE38VnSEP879MBKV1ZyDq2YrnEtOn7_VfzjbkaAtpfEALw_wcB
> >>>
> >>> Somebody had pointed out yet another source of connectorized fibers
> >> ("patch
> >>> cords") to me, but I cannot find the name
> >>> at the moment.
> >>>
> >>> Dana   K8YUM
> >>>
> >>>
> >>> On Sat, Aug 28, 2021 at 11:52 AM AC0XU (Jim) <
> James.Schatzman at ac0xu.com>
> >>> wrote:
> >>>
> >>>> I am hoping that you can help me about a couple of things:
> >>>>
> >>>> 1) My time-nuts summaries sometimes appear unformatted and unreadable.
> >> All
> >>>> the text from all the postings is crammed together without spacing.
> How
> >> can
> >>>> I fix it?
> >>>>
> >>>> 2) I want to distribute 10 MHz references by fiber. There are
> >>>> RF-over-Fiber products available, but too expensive for me (thousands
> of
> >>>> $$$ per xmit/rcv set).  I am thinking that it should be possible to
> use
> >>>> fiber Ethernet components to do this. I don't mean IEEE 1588 but a
> much
> >>>> simpler, no-computer-required, solution. Possibly just converting sine
> >> wave
> >>>> (coax) to square wave (fiber) to sine wave (coax). I am looking for a
> >> low
> >>>> cost solution. Any thoughts or recommendations??
> >>>>
> >>>> Thanks!
> >>>>
> >>>> Jim
> >>>> _______________________________________________
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> >>>>
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