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

[Bob kb8tq]

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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