No worries, SPDIF or more specifically TOSLINK only uses a Red LED for
optical audio transfer. My Laptop has an SPDIF connector shining out the
front it is hardly likely to be a dangerous laser where a child could
easily put their eye to it. I hope.

Eddie G3ZJO


-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Ken
Sent: 29 December 2009 21:37
To: [email protected]
Subject: Re: LF: Re: Re: RE: Noise cancelling by using optic
transmission of RX signals

If it is red then the optical wavelength is about 850nm, what you also
need 
to know is the type of fibre on the sound card, i.e, multi mode or
single 
mode. Multi mode fibre is usually 50/125 microns and single mode 9/125 
microns, the first number is the core diameter, the second the overall
fibre 
diameter, as you can see you do not want to try and launch a multi mode 
light source into a single mode fibre..

73s.
Ken.
M0KHW
----- Original Message ----- 
From: "John RABSON" <[email protected]>
To: <[email protected]>
Sent: Tuesday, December 29, 2009 9:31 AM
Subject: Re: LF: Re: Re: RE: Noise cancelling by using optic
transmission of 
RX signals


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 
manual.

F5VLF

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

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

>Radio Amateurs BEWARE - Appliance Operators DO NOT TOUCH
>
>G3KEV
>
>
>----- 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
>signals
>
>
>> 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
>> ___________________________________________________________
>> Preisknaller: WEB.DE DSL Flatrate für nur 16,99 Euro/mtl.!
>> http://produkte.web.de/go/02/
>>
>>
>>
>>






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