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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