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

["Ken" <ken.h.wright@btinternet.com>]

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" <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 
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" <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 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
> > ___________________________________________________________
> > Preisknaller: WEB.DE DSL Flatrate für nur 16,99 Euro/mtl.!
> > http://produkte.web.de/go/02/