Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mc05.r1000.mx.aol.com (Internet Inbound) with ESMTP id D6AC438000108; Sun, 9 Oct 2011 08:15:22 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1RCsGt-0006SP-4a for rs_out_1@blacksheep.org; Sun, 09 Oct 2011 13:14:23 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1RCsGs-0006SG-KB for rsgb_lf_group@blacksheep.org; Sun, 09 Oct 2011 13:14:22 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1RCsGr-0006z7-HQ for rsgb_lf_group@blacksheep.org; Sun, 09 Oct 2011 13:14:22 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id p99CEK9g014522 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 9 Oct 2011 14:14:20 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id p99CEJoh016682 for ; Sun, 9 Oct 2011 14:14:19 +0200 Message-ID: <4E918FF1.1010407@iup.uni-heidelberg.de> Date: Sun, 09 Oct 2011 14:13:37 +0200 From: =?ISO-8859-15?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4E91694C.8060900@orange.fr> <4E9169AD.8090609@wanadoo.fr> <4E918C0E.30401@freenet.de> In-Reply-To: <4E918C0E.30401@freenet.de> X-Spam-Score: 1.6 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,HTML_TAG_EXIST_TBODY=0.126,RATWARE_GECKO_BUILD=1.426 Subject: Re: Fwd: Re: LF: Laser link... Content-Type: multipart/alternative; boundary="------------080207070009000905020604" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30,HTML_MESSAGE, HTML_TAG_EXISTS_TBODY autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:463783744:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d604d4e91905a15c2 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------080207070009000905020604 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id p99CEK9g014522 Hi Wolf, Thanks for the comments. Do you have a hint for a suitable CMOS VCO that=20 is easy to get (Reichelt ;-) ) and good for 137 kHz? 73, Stefan Am 09.10.2011 13:57, schrieb wolf_dl4yhf: > Hi all, > > just my few cents.. > > if you frequency-modulate the LF (or VLF) signal with a reasonable=20 > square-wave carrier, there are no problems with linearity. Any=20 > reasonable CMOS VCO will suffice. Similar for the receiver. Absolutely=20 > no need to 'go digital', when the supplied power is limited. > > Cheers, > Wolf . > > (who tried something similar with a red 'Luxeon' LED some time ago,=20 > but the system wasn't reliable lacking affordable narrow-band optical=20 > filters for the receiver) > > Am 09.10.2011 11:30, schrieb Jean-L. RAULT: >> >> >> >> =09 >> >> =09 >> >> =09 >> >> =09 >> >> >> >> I wonder if an analog laser link has enough linearity to carry your LF >> signals (bad lienarity =3D=3D> noise and intermod effects) >> A digital laser link would be better, but would increase the complexit= y >> of the project :o) >> >> Jean-Louis F6AGR >> >> >> >> >> >> Le 08/10/2011 19:26, Stefan Sch=E4fer a =E9crit : >> > Thanks Dex and Scott, >> > >> > Enough stuff to study now. The seconds page seems more useful for m= e. >> > Ok about that OT. >> > >> > 73, Stefan >> > >> > Am 08.10.2011 21:09, schrieb Scott Tilley: >> >> Hi Stefan >> >> >> >> http://www.k3pgp.org/laser.htm >> >> >> >> I use his detector and modulator circuits for my system. >> >> >> >> 73 Scott >> >> >> >> >> >> >> >> >> >> On 10/8/2011 10:09 AM, Stefan Sch=E4fer wrote: >> >>> LF, >> >>> >> >>> Just thought about trying a LF RX in the forest and feed the sign= al >> >>> via a laser link to the building here. There is a good direct vie= w >> >>> to several suitable places, a good 1000m distant from the city. A >> >>> simple laser diode, driven at 15 to 20 mA should work fine for so= me >> >>> hours when having a solar panel that charges during the day. You >> >>> know these small lamps for the garden with a solar panel, switchi= ng >> >>> on automatically when it gets dark... >> >>> Just seen HA6PC at OE3GHB-grabber but nothing here or at DF6NM (y= es >> >>> Mal, i know, you've all worked them in the past...). >> >>> Pure AM is probably not the best choice, rather FM. >> >>> Does someone of you has useful experiance of such a laser system = or >> >>> even a ready to use circuit or some hints about a compact IC that >> >>> does the job? >> >>> >> >>> No warnings about the danger of laser light please. >> >>> >> >>> 73, Stefan/DK7FC >> >>> >> >>> PS: Sri for beeing a bit OT >> >>> >> >>> >> >> >> > >> > >> >> =20 > --------------080207070009000905020604 Content-Type: text/html; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id p99CEK9g014522 Hi Wolf,

Thanks for the comments. Do you have a hint for a suitable CMOS VCO that is easy to get (Reichelt ;-) ) and good for 137 kHz?

73, Stefan

Am 09.10.2011 13:57, schrieb wolf_dl4yhf:
Hi all,

just my few cents..

if you frequency-modulate the LF (or VLF) signal with a reasonable square-wave carrier, there are no problems with linearity. Any reasonable CMOS VCO will suffice. Similar for the receiver. Absolutely no need to 'go digital', when the supplied power is limited.

Cheers,
=A0=A0=A0 Wolf .

(who tried something similar with a red 'Luxeon' LED some time ago, but the system wasn't reliable lacking affordable narrow-band optical filters for the receiver)

Am 09.10.2011 11:30, schrieb Jean-L. RAULT: 












I wonder if an analog laser link has enough linearity to carry y=
our LF=20
signals (bad lienarity =3D=3D> noise and intermod effects)
A digital laser link would be better, but would increase the complexity=20
of the project :o)

Jean-Louis F6AGR





Le 08/10/2011 19:26, Stefan Sch=E4fer a =E9crit :
> Thanks Dex and Scott,
>
> Enough stuff to study now. The seconds page seems more useful for me.
> Ok about that OT.
>
> 73, Stefan
>
> Am 08.10.2011 21:09, schrieb Scott Tilley:
>> Hi Stefan
>>
>> http://www.k3pgp.org/laser.htm
>>
>> I use his detector and modulator circuits for my system.
>>
>> 73 Scott
>>
>>
>>
>>
>> On 10/8/2011 10:09 AM, Stefan Sch=E4fer wrote:
>>> LF,
>>>
>>> Just thought about trying a LF RX in the forest and feed the=
 signal=20
>>> via a laser link to the building here. There is a good direc=
t view=20
>>> to several suitable places, a good 1000m distant from the ci=
ty. A=20
>>> simple laser diode, driven at 15 to 20 mA should work fine f=
or some=20
>>> hours when having a solar panel that charges during the day.=
 You=20
>>> know these small lamps for the garden with a solar panel, sw=
itching=20
>>> on automatically when it gets dark...
>>> Just seen HA6PC at OE3GHB-grabber but nothing here or at DF6=
NM (yes=20
>>> Mal, i know, you've all worked them in the past...).
>>> Pure AM is probably not the best choice, rather FM.
>>> Does someone of you has useful experiance of such a laser sy=
stem or=20
>>> even a ready to use circuit or some hints about a compact IC=
 that=20
>>> does the job?
>>>
>>> No warnings about the danger of laser light please.
>>>
>>> 73, Stefan/DK7FC
>>>
>>> PS: Sri for beeing a bit OT
>>>
>>>
>>
>
>

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