Return-Path: Received: from rly-mg08.mx.aol.com (rly-mg08.mail.aol.com [172.20.83.114]) by air-mg09.mail.aol.com (v126.13) with ESMTP id MAILINMG092-a2d4b2974e619a; Wed, 16 Dec 2009 19:02:18 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-mg08.mx.aol.com (v125.7) with ESMTP id MAILRELAYINMG087-a2d4b2974e619a; Wed, 16 Dec 2009 19:01:44 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NL3kp-0003jV-HG for rs_out_1@blacksheep.org; Wed, 16 Dec 2009 23:58:03 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NL3ko-0003jM-TE for rsgb_lf_group@blacksheep.org; Wed, 16 Dec 2009 23:58:02 +0000 Received: from lnx500.hrz.tu-darmstadt.de ([130.83.156.225]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NL3mr-0008WH-0c for rsgb_lf_group@blacksheep.org; Thu, 17 Dec 2009 00:00:11 +0000 Received: from FILE-SERVER-HST.hst.e-technik.tu-darmstadt.de (File-Server-HST.hst.e-technik.tu-darmstadt.de [130.83.212.129]) by lnx500.hrz.tu-darmstadt.de (8.14.2/8.14.2/HRZ/PMX) with SMTP id nBGNdxdf031422 for ; Thu, 17 Dec 2009 00:39:59 +0100 (envelope-from schaefer@hst.tu-darmstadt.de) Received: from [127.0.0.1] (helo=File-Server-HST.hst.e-technik.tu-darmstadt.de) by FILE-SERVER-HST.hst.e-technik.tu-darmstadt.de with AVK MailGateway; for ; Thu, 17 Dec 2009 01:00:33 +0100 Content-class: urn:content-classes:message MIME-Version: 1.0 X-MimeOLE: Produced By Microsoft Exchange V6.5 Date: Thu, 17 Dec 2009 01:00:36 +0100 Message-ID: <38A51B74B884D74083D7950AD0DD85E828ACB7@File-Server-HST.hst.e-technik.tu-darmstadt.de> In-Reply-To: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: LF: Noise cancelling by using optic transmission of RX signals; amendment Thread-Index: Acp+lxx/qujYoWOaRWimQ3vuSUXi+QADtvmw From: =?iso-8859-1?Q?Stefan_Sch=E4fer?= To: X-AVK-Virus-Check: AVB 19.627;16.12.2009 X-PMX-TU: seen v0.99a by 5.5.8.383112, Antispam-Engine: 2.7.2.376379, Antispam-Data: 2009.12.16.234819 X-PMX-SPAMCHECK: outgoing mail X-Karma: unknown: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CA7EAB.F3ECD9C3" Subject: LF: Noise cancelling by using optic transmission of RX signals; amendment X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.3 required=5.0 tests=HTML_50_60, HTML_FONTCOLOR_UNKNOWN,HTML_MESSAGE 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-IP: 193.82.116.20 X-Mailer: Unknown (No Version) ------_=_NextPart_001_01CA7EAB.F3ECD9C3 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Dave, LF,=20 Yes, a transverter would be an other possibility but it would be much more= complex I think, just when regarding the needed power (compared to a LED)= . And you would get new problems when you receive on a "new" frequency, e.= g. in the 2m band when there is another noise that is not coming from LF= ;-) =20 I have a further idea:=20 DL2CH, Hans-Hellmuth Cuno (who was even qrv on LF before some years) prese= nted a laser TRX in the CQDL (I think 2001). I have built this TRX and did= some fascinating tests with a simple laser diode out of a laser pointer.= I satisfactorily transmitted music/AF via the laser beam on a distance of= 200m without a noticeable quality loss.=20 Instead of a transmitting LED and fibre optic cable it should be possible= to transmit a LF signal via a laser beam to the shack. We could call it= a 2,2km/650nm transverter ;-) Let's imagine someone has a garden in a distance of 200m, perhaps on a hil= lside apart the city where no qrm is, but with a road between the house th= at makes it impossible to use a cable. So he could operate e.g. a grabber= to the internet from that clear region! Sure, if there is strong rain or= fog and so on, it will be difficult but that are all possibilities, one= could try without the need for much energy! I would try this with my lase= r TRX but there is no need for me (not yet) in the moment. As we know, there are existing internet links via laser beams since many= years...=20 Another word to the fibre optical transmission: Sure there are many method= s suppressing noise coming from the coax screen. The optical solution is= just one. But I think the advantage is, that this method decouples the pr= eamp from the RX for 100%, say with an attenuation of 1000000000000000 dB= (to come back for joking ;-) ). There is no need for choosing the right= core out of the right material and the right number of turns at both side= s of the right cable that is placed in the right way and so on and on. If= the optic method is used, this theme is just finished, just like the ques= tion "would it even be better when I apply 10 turns more or take 2 cores= and/or bury the coax 5m into the earth?"=20 Perhaps it's no so easy as I think but in the moment it seems to be a good= solution for me that is really working fine. GN or GM de Stefan/DK7FC =20 =20 73, Stefan =20 -----Urspr=FCngliche Nachricht----- Von: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacks= heep.org] Im Auftrag von Dave G3WCB Gesendet: Mittwoch, 16. Dezember 2009 22:27 An: rsgb_lf_group@blacksheep.org Betreff: LF: RE: Noise cancelling by using optic transmission of RX signal= s =20 Hello, Stefan. =20 This is very interesting. I have a MiniWhip on a pole some distance from= the house, and it seems that most of the interference (ADSL hash) seems= to be re-radiated by the coax outer and picked up by the antenna. =20 A relatively short optical link of one or two metres may still reduce the= pick-up, as it would break the "copper" connection to the antenna. =20 Alternatively, it might be possible to transvert the amplified LF signal= up to a vhf frequency and then set up a remote RX some distance away. =20 You could switch the power on and off by using a pressure switch from a di= scarded washing machine connected to the shack by a lenght of 6mm plastic= tubing. Apply slight positive pressure to turn on the antenna circuitry! =20 73, Dave G3WCB IO91RM nr Windsor, S.E. England.=20 =20 ------_=_NextPart_001_01CA7EAB.F3ECD9C3 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Hi Dave, LF,

Yes, a transverter would= be an other possibility but it would be much more complex I think, just when regarding the needed powe= r (compared to a LED). And you would get new problems when you receive on a= “new” frequency, e.g. in the 2m band when there is another noise that is not com= ing from LF ;-)

 

I have a further idea:

DL2CH, Hans-Hellmuth Cuno= (who was even qrv on LF before some years) presented a laser= TRX in the CQDL (I think 2001). I have built this TRX and did some fascinating= tests with a simple laser diode out of a laser pointer. I satisfactorily transmi= tted music/AF via the laser beam on a distance of 200m without a noticeable quality loss= .

Instead of a transmitting= LED and fibre optic cable it should be possible to transmit a LF signal via a laser beam to th= e shack. We could call it a 2,2km/650nm transverter ;-)

Let’s imagine someon= e has a garden in a distance of 200m, perhaps on a hillside apart the city where no qrm is, bu= t with a road between the house that makes it impossible to use a cable. So= he could operate e.g. a grabber to the internet from that clear region! Sure,= if there is strong rain or fog and so on, it will be difficult but that are= all possibilities, one could try without the need for much energy! I would try= this with my laser TRX but there is no need for me (not yet) in the moment.

As we know, there are exis= ting internet links via laser beams since many years…

Another word to the fibre= optical transmission: Sure there are many methods suppressing noise coming from the coax screen.= The optical solution is just one. But I think the advantage is, that this meth= od decouples the preamp from the RX for 100%, say with an attenuation of 1000000000000000 dB (to come back for joking ;-) ). There is no need for choosing the right core out of the right material and the right number of= turns at both sides of the right cable that is placed in the right way and so on= and on. If the optic method is used, this theme is just finished, just like th= e question “would it even be better when I apply 10 turns more or take= 2 cores and/or bury the coax 5m into the earth?”

Perhaps it’s no so= easy as I think but in the moment it seems to be a good solution for me that is really working fi= ne.

GN or GM de Stefan/DK7FC

 

 

73, Stefan

 

-----Urspr=FCngliche Nachrich= t-----
Von: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] Im Auftrag von Dave G3WCB
Gesendet: Mittwoch, 16. Dez= ember 2009 22:27
An: rsgb_lf_group@blackshee= p.org
Betreff: LF: RE: Noise canc= elling by using optic transmission of RX signals

 <= /span>

Hello, Stefan.

 

This is very interesting. I have= a MiniWhip on a pole some distance from the house, and it seems that most of the interference (ADSL hash) see= ms to be re-radiated by the coax outer and picked up by the antenna.

 

A relatively short optical link= of one or two metres may still reduce the pick-up, as it would break the "copper" connection to= the antenna.

 

Alternatively, it might be possib= le to transvert the amplified LF signal up to a vhf frequency and then set up a remote RX some distance awa= y.

 

You could switch the power on and= off by using a pressure switch from a discarded washing machine connected to the shack by a lenght of 6mm plastic tubing. Apply slight positive pressure to turn on the ant= enna circuitry!

 

73, Dave G3WCB IO91RM nr Windsor,= S.E. England. 

 

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