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

[Lux, Jim]

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.