Return-Path: Received: from rly-ma10.mx.aol.com (rly-ma10.mail.aol.com [172.20.116.54]) by air-ma05.mail.aol.com (v121_r5.5) with ESMTP id MAILINMA053-8d049647789184; Wed, 07 Jan 2009 04:36:24 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-ma10.mx.aol.com (v121_r4.4) with ESMTP id MAILRELAYINMA102-8d049647789184; Wed, 07 Jan 2009 04:36:11 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LKUpA-0004pO-AR for rs_out_1@blacksheep.org; Wed, 07 Jan 2009 09:35:40 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LKUp9-0004pF-NJ for rsgb_lf_group@blacksheep.org; Wed, 07 Jan 2009 09:35:39 +0000 Received: from web28101.mail.ukl.yahoo.com ([217.146.182.121]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1LKUp9-00047n-Ij for rsgb_lf_group@blacksheep.org; Wed, 07 Jan 2009 09:35:39 +0000 Received: (qmail 77538 invoked by uid 60001); 7 Jan 2009 09:35:33 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.co.uk; h=X-YMail-OSG:Received:X-Mailer:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type:Message-ID; b=tqf+GC2/3CroQuQaH6RIjn0vveRNZ1sUL9UjBWN+z8thvS/xd75jd9W09YseDUo6XODfRaObKq1JaoGv8ipbxVxhViabRmaEwc4CVN/qBLgxLQAem6EXZ7YriUTBqCh+vXP/qPSFIl4Zia4lwVkXcyWkEEgxj7kH1f83zoYn7Xg=; X-YMail-OSG: d.T0OfAVM1mtfdQwKRwJ_7jJPOdD5uKR7W5VAkOdGW.daXYRXB75GvN9igp61gW9053IAAPN5hhu39uhQgMwzixNo7pdChNRRRcVB35F3sxI.0uDUBWIxTsvU79KHz.jj9vNuTd9FDNZsXYuQGLmYDuiT7fON6TkwpYBK6Tz46l1xheIZiV16Iq6Me4c_uGAKtejUC4Z9aNSaQ-- Received: from [86.130.69.9] by web28101.mail.ukl.yahoo.com via HTTP; Wed, 07 Jan 2009 09:35:33 GMT X-Mailer: YahooMailWebService/0.7.260.1 Date: Wed, 7 Jan 2009 09:35:33 +0000 (GMT) From: M0FMT To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 Message-ID: <879844.77154.qm@web28101.mail.ukl.yahoo.com> X-Karma: 0: DomainKey-Status: good (testing) Subject: Re: LF: Razor blade RX .... Try a Cohere? Content-Type: multipart/alternative; boundary="0-2141442297-1231320933=:77154" 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=CLICK_BELOW,HTML_20_30, HTML_LINK_CLICK_HERE,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 --0-2141442297-1231320933=:77154 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable =C2=A0Hi Rik and LF =C2=A0 But that's the point, =C2=A0an envelope detector will not detect CW (ON / OF= F Keying) unless A/ you have a local oscillator (DC rx) to create a beat in=20= the detector, added complication in design or B/ unless the carrier has got=20= noise on it (sparker) or it is modulated, added bandwidth for no extra intel= ligence. =C2=A0 If we go away from a simple detector RX and add amplification to an envelope= detector the recovered DC from a CW signal could be used to operate a switc= h to activate a Buzzer, light or side tone oscillator but=C2=A0I don't think= thats in the spirit of the spirit of the challenge. =C2=A0 However a Coherer detector does everything for CW in one simple easy to cons= truct mechanical device with no fiddling with cats whiskers or the risk of c= utting a vital artery with a sharp razor blade! And no need for high impedan= ce cans. =C2=A0 I rest my case for the Coherer detector.I think Edouard Branly=C2=A0and Oliv= er Lodge=C2=A0got it dead right! =C2=A0 The challenge is to make a QSO using the Razor Blade RX I am working on it.=20= But a counter Challenge is to use a Coherer for a two way QSO, I am working=20= on that also. However it's very cold in my garage right now so don't expect=20= a result from me soon but better setup ops may have a result sooner. =C2=A0 Regards 73 petefmt --- On Wed, 7/1/09, Rik Strobbe wrote: From: Rik Strobbe Subject: Re: LF: Razor blade RX .... Try a Cohere? To: rsgb_lf_group@blacksheep.org Date: Wednesday, 7 January, 2009, 8:11 AM MCW: what a waste of bandwidth, Mal will allert OFCOM ! 73, Rik=C2=A0 ON7YD - OR7T At 00:42 7/01/2009, you wrote: =C2=A0No problem! Use MCW! Has been typical for 500 kHz. 73 DJ1ZB =C2=A0"M0FMT" schrieb:=20 Hi Mal and LF =C2=A0 I am disapointed in you Mal to be considering an envelope detector. A true C= W man, I would have thought, should only entertain the use of a Cohere detec= tor! =C2=A0 Having played with them, I was surprised how well they work over a range 136= kc/s to 433mc/s (the extent of my power RF O/P) probably work over a much la= ger range of frequencies but not tested by me. =C2=A0 http://home.earthlink.net/~lenyr/coherer.htm =C2=A0 73 pefmt =C2=A0 --- On Tue, 6/1/09, mal hamilton wrote: From: mal hamilton Subject: Re: LF: Razor blade RX To: rsgb_lf_group@blacksheep.org Date: Tuesday, 6 January, 2009, 9:21 PM Your own cct and ideas and the headphone construction. Not info from the web= . g3kev =C2=A0 ----- Original Message -----=20 From: riese-k3djc@juno.com=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, January 06, 2009 7:58 PM Subject: Re: LF: Razor blade RX 310113517964=C2=A0=C2=A0 E bay too =C2=A0 On Tue, 6 Jan 2009 18:00:45 -0000 "mal hamilton" wri= tes: Since I mentioned a Razor blade and fence wire RX a while back I have had se= veral requests for a circuit. To give others the opportunity to submit a cct= I will await replies. This method was used successfully=C2=A0 at Coldiz and= other POW camps to receive BBC broadcasts. Let us know how you would approach the subject. This is applicable to MF/LF=20= since the broadcasts at the time were receicved on these bands. Build one and have a QSO using this RX g3kev =C2=A0 =C2=A0 ____________________________________________________________=20 Fashion Design Education - Click Here! No virus found in this incoming message. Checked by AVG - http://www.avg.com=20 Version: 8.0.176 / Virus Database: 270.10.3/1877 - Release Date: 1/5/2009 7:= 20 PM =C2=A0=20 Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm for more inform= ation.=20 =20 --0-2141442297-1231320933=:77154 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
=20 --0-2141442297-1231320933=:77154--
 Hi Rik and LF
 
But that's the point,  an envelope detector will not detect CW (ON= / OFF Keying) unless A/ you have a local oscillator (DC rx) to create a bea= t in the detector, added complication in design or B/ unless the carrier has= got noise on it (sparker) or it is modulated, added bandwidth for no extra=20= intelligence.
 
If we go away from a simple detector RX and add amplification to an env= elope detector the recovered DC from a CW signal could be used to operate a=20= switch to activate a Buzzer, light or side tone oscillator but I don't=20= think thats in the spirit of the spirit of the challenge.
 
However a Coherer detector does everything for CW in one simple easy to= construct mechanical device with no fiddling with cats whiskers or the risk= of cutting a vital artery with a sharp razor blade! And no need for high im= pedance cans.
 
I rest my case for the Coherer detector.I think Edouard Branly=  and Olive= r Lodge got it dead right!
 
The challenge is to make a QSO using the Razor Blade RX I am working on= it. But a counter Challenge is to use a Coherer for a two way QSO, I am wor= king on that also. However it's very cold in my garage right now so don't ex= pect a result from me soon but better setup ops may have a result sooner.
 
Regards 73 petefmt

--- On Wed, 7/1/09, Rik Strobbe <rik.strobbe@fys.kuleuven.be> wrote:
From: Rik Strobbe <rik.strobbe@fys.kuleuven.be>Subject: Re: LF: Razor blade RX .... Try a Cohere?
To: rsgb_lf_group@bl= acksheep.org
Date: Wednesday, 7 January, 2009, 8:11 AM

MCW: what a waste of bandwidth, Mal will allert OFCO= M !

73, Rik  ON7YD - OR7T

At 00:42 7/01/2009, you wrote:<= BR>
 No problem! Use MCW!=20= Has been typical for 500 kHz.

73 DJ1ZB


 "M0FMT" <m= 0fmt@yahoo.co.uk> schrieb:
Hi Mal and LF
 
I am disapointed in you Mal to be considering an envelope detector. A tr= ue CW man, I would have thought, should only entertain the use of a Cohere d= etector!
 
Having played with them, I was surprised how well they work over a range= 136kc/s to 433mc/s (the extent of my power RF O/P) probably work over a muc= h lager range of frequencies but not tested by me.
 
http://home.earthlink.net/~lenyr/coherer.htm
 
73 pefmt


 


--- On Tue, 6/1/09, mal hamilton <g3kevmal@talktalk.net> wrote:
From: mal hamilton <g3kevmal@talktalk.net>
Subject: Re: LF: Razor blade RX
To: rsgb_lf_group@blacksheep.org
Date: Tuesday, 6 January, 2009, 9:21 PM

Your own cct and ideas and the headphone construction. No= t info from the web.
g3kev
 
----- Original Message -----
From: riese-k3djc@juno.com
To: rsgb_lf_group@blacksheep.org
Sent: Tuesday, January 06, 2009 7:58 PM
Subject: Re: LF: Razor blade RX

310113517964   E bay too
 
On Tue, 6 Jan 2009 18:00:45 -0000 "mal hamilton" <g3kevmal@talktalk.net> writes:
Since I mentioned a Razor blade and fence wire RX a while= back I have had several requests for a circuit. To give others the opportun= ity to submit a cct I will await replies. This method was used successfully&= nbsp; at Coldiz and other POW camps to receive BBC broadcasts.
Let us know how you would approach the subject. This is applicable to MF= /LF since the broadcasts at the time were receicved on these bands.
Build one and have a QSO using this RX
g3kev
 
 



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