On 8/28/21 9:51 AM, AC0XU (Jim) 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??
Take a look at the standard fiber optic modules that plug into a
switch. They typically have a very simple logic level interface to the
diode.
here's a $27 dollar example - but I think you might want to iterate
around - I recall finding cheaper ones - part of it is which fiber
cable/connector you use, and part of it is what the backside interface
looks like. I can't find it now, but you can get the mating electrical
connector, or you can solder wires.
https://www.fs.com/products/11555.html?attribute=77&id=219732
The OVRO-LWA uses fiber to connect the remote antenna preamp with ~1km
fiber to the receiver at 30-90 MHz - they use a laser diode on the Tx
end and a receiver on the Rx end. They're pretty cheap. They've done
quite a bit of testing of various schemes, and measuring noise
performance and loss.
dig around here: http://www.tauceti.caltech.edu/LWA/lwamemos.html
In particular memo 12
http://www.tauceti.caltech.edu/LWA/memos/memo12.pdf - gives a couple
part numbers.
If you need Sandy Weinreb's report (from 2019, referenced by Larry
D'Addario in memo 12) - you could probably email him, or I can look for
a copy.
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