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Re: LF: Re: Re: RE: Noise cancelling by using optic transmission of RX

To: [email protected]
Subject: Re: LF: Re: Re: RE: Noise cancelling by using optic transmission of RX signals
From: "John RABSON" <[email protected]>
Date: Tue, 29 Dec 2009 10:31:04 +0100
In-reply-to: <[email protected]>
References: <[email protected]> <[email protected]> <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
Agreed we should be careful.  My Creative Labs soundcard (external USB) has 
SPDIF optical connectors as well as electrical.  The Optical Out connector 
emits a faint red light but I can't find any mention of safety in the user 


*********** REPLY SEPARATOR  ***********

On 18/12/2009 at 09:16 mal hamilton wrote:

>Radio Amateurs BEWARE - Appliance Operators DO NOT TOUCH
>----- Original Message -----
>From: "Ken" <[email protected]>
>To: <[email protected]>
>Sent: Thursday, December 17, 2009 10:43 AM
>Subject: LF: Re: RE: Noise cancelling by using optic transmission of RX
>> Optical fibres are fine for transmission and remove all the problems of
>> interference and cross talk at a stroke, but please be careful and
>> optical safety precautions when using lasers and other light sources. I
>> worked on optical systems for many years during my time with BT, and
>> safety took priority over every thing else. All optical fibres need to
>> 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
>> In theory it's a good Idea which I had some weeks before without working
>> 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
>> 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
>> 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
>> stand weather/UV and mechanical conditions outside for a long time.
>> Horst DO1KHS
>> ___________________________________________________________
>> Preisknaller: WEB.DE DSL Flatrate für nur 16,99 Euro/mtl.!

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