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 <[email protected]> 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) <[email protected]>
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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