I have a small number of ex equipment semiconductor quantum well semiconductor
lasers (1550nm) and PIN diodes on PCB cards. These are pigtailed with single
mode fibre terminated in FC connectors. The cards have an FC bulkhead adaptor
so that they can be connected together to form a short one-way radio over fibre
link. These are modern (current) devices and capable of carrying radio over
fibre from DC to about 2.0 - 2.4GHz. This would form a high performance, but
short, fibre link (antenna isolator), but with access to some SM fibre with FC
connectors the link could be up to 100km long, depending on a number of factors!
These are offered for a small donation to the Bawdsey remote receiver project,
plus postage. Contact me off list if you are interested. I must stress that I
am unable to provide further assistance in setting up the fibre optic links or
devices. You are on your own!
Relevant optical safety, using lasers, needs to be observed.
[email protected]
73 de Sam
On 17 Dec 2009, at 10:43, "Ken" <[email protected]> wrote:
Optical fibres are fine for transmission and remove all the problems of
interference and cross talk at a stroke, but please be careful and observe
optical safety precautions when using lasers and other light sources. I worked
on optical systems for many years during my time with BT, and optical safety
took priority over every thing else. All optical fibres need to have a perfect
cleave on the ends, and the connectors be absolutely clean, if you are not
launching into an optical connector then alignment will be a problem, similarly
at the receive end.
73.
Ken
M0KHW
----- Original Message ----- From: "Horst Stöcker" <[email protected]>
To: <[email protected]>
Sent: Thursday, December 17, 2009 9:01 AM
Subject: LF: RE: Noise cancelling by using optic transmission of RX signals
In theory it's a good Idea which I had some weeks before without working it out.
Years before I also have made tests with FTA (free to air) optical
transmissions with a DL2CH-Transceiver and a TRX-Kit by Aatis which is quite
much simpler.
Even with that it was no problem to link between two points about a few meters.
In this case you should think about an IR-LED. Unfortunately, the Aatis
receiver has a photo transistor instead of a diode. But it should be no great
deal to modify that.
The problems with FTA optic transmission for this application are imho:
- You have to be sure, that no one can be injured by the laser beam, especially
at unattended operation.
- Think about how many hours/the beam has it's full power before becoming much
weaker.
- The optics must be kept clean. This could be a problem if the units are out
of reach.
- The units have to be mounted absolutely stable. For Example, on a swinging
fibre rod you'll never bring a laser beam exactly to the rx area.
I bet, (FTA) optical transmission just changes one problem with a few others.
But the transmission with optical cable seems interesting.
What type of cable do you suggest? I do not think, my TOS-Link cable would
stand weather/UV and mechanical conditions outside for a long time.
Horst DO1KHS
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