From: "g3zjo" <g3zjo@npton.plus.com>
To: <rsgb_lf_group@blacksheep.org>
Date: Tue, 29 Dec 2009 21:59:28 -0000
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Subject: RE: LF: Re: Re: RE: Noise cancelling by using optic  transmission of RX signals
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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: owner-rsgb_lf_group@blacksheep.org
[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Ken
Sent: 29 December 2009 21:37
To: rsgb_lf_group@blacksheep.org
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=20
to know is the type of fibre on the sound card, i.e, multi mode or
single=20
mode. Multi mode fibre is usually 50/125 microns and single mode 9/125=
=20
microns, the first number is the core diameter, the second the overall
fibre=20
diameter, as you can see you do not want to try and launch a multi mod=
e=20
light source into a single mode fibre..

73s.
Ken.
M0KHW
----- Original Message -----=20
From: "John RABSON" <john.rabson@numeo.fr>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, December 29, 2009 9:31 AM
Subject: Re: LF: Re: Re: RE: Noise cancelling by using optic
transmission of=20
RX signals


Agreed we should be careful.  My Creative Labs soundcard (external USB=
)
has=20
SPDIF optical connectors as well as electrical.  The Optical Out
connector=20
emits a faint red light but I can't find any mention of safety in the
user=20
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" <ken.h.wright@btinternet.com>
>To: <rsgb_lf_group@blacksheep.org>
>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 problem=
s
of
>> interference and cross talk at a stroke, but please be careful and
>observe
>> optical safety precautions when using lasers and other light source=
s.
I
>> worked on optical systems for many years during my time with BT, an=
d
>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 St=F6cker" <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 uni=
ts
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 cabl=
e
>would
>> stand weather/UV and mechanical conditions outside for a long time.
>>
>> Horst DO1KHS
>> ___________________________________________________________
>> Preisknaller: WEB.DE DSL Flatrate f=FCr nur 16,99 Euro/mtl.!
>> http://produkte.web.de/go/02/
>>
>>
>>
>>






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