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Message-ID: <6F962616C1CC4C1B844AF099CB1BB55D@lindavideo>
From: "Ken" <ken.h.wright@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <1542517694@web.de>
Date: Thu, 17 Dec 2009 10:43:27 -0000
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Subject: LF: Re: RE: Noise cancelling by using optic transmission of RX signals
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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" <horst.stoecker@web.de>
To: <rsgb_lf_group@blacksheep.org>
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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