Return-Path: Received: from rly-db03.mx.aol.com (rly-db03.mail.aol.com [172.19.130.78]) by air-db10.mail.aol.com (v121_r4.4) with ESMTP id MAILINDB103-ab9496491921d; Wed, 07 Jan 2009 06:27:29 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-db03.mx.aol.com (v121_r4.4) with ESMTP id MAILRELAYINDB037-ab9496491921d; Wed, 07 Jan 2009 06:27:19 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LKWYb-0007Ce-JM for rs_out_1@blacksheep.org; Wed, 07 Jan 2009 11:26:41 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LKWYZ-0007CR-N7 for rsgb_lf_group@blacksheep.org; Wed, 07 Jan 2009 11:26:39 +0000 Received: from smtp-out-1.talktalk.net ([62.24.128.231] helo=smtp.talktalk.net) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1LKWYX-0007zW-Mc for rsgb_lf_group@blacksheep.org; Wed, 07 Jan 2009 11:26:39 +0000 X-Path: TTSMTP X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: At8GAJwgZElOlWZt/2dsb2JhbACCQS4hgUaGXQbEKoV1 Received: from unknown (HELO mal769a60aa920) ([78.149.102.109]) by smtp.talktalk.net with SMTP; 07 Jan 2009 11:26:31 +0000 Message-ID: <005d01c970ba$ca1f0bb0$0301a8c0@mal769a60aa920> From: "mal hamilton" To: References: <879844.77154.qm@web28101.mail.ukl.yahoo.com> Date: Wed, 7 Jan 2009 11:26:31 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Spam-Score: 0.1 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,HTML_TAG_EXIST_TBODY=0.126 Subject: Re: LF: Razor blade RX .... Try a Cohere? Content-Type: multipart/alternative; boundary="----=_NextPart_000_005A_01C970BA.C9E5D340" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.7 required=5.0 tests=CLICK_BELOW,HTML_20_30, HTML_LINK_CLICK_HERE,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-IP: 193.82.116.20 ------=_NextPart_000_005A_01C970BA.C9E5D340 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Pete and co You are wandering away from the subject. My question was not on the merits o= f detectors etc, simply how to build a razor blade detector and suitable ear= phone using scrap parts available in a trench or Jail, for instance in 1940 I have all the answers if you get stuck and I did not get it from an interne= t source. Its fundamental knowledge that a radio amateur should know and esp= ecially if the BIG BANG should happen g3kev =20 ----- Original Message -----=20 From: M0FMT=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Wednesday, January 07, 2009 9:35 AM Subject: Re: LF: Razor blade RX .... Try a Cohere? 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 beat=20= in the detector, added complication in design or B/ unless the carrier has g= ot noise on it (sparker) or it is modulated, added bandwidth for no extra in= telligence. If we go away from a simple detector RX and add amplification to an=20= envelope detector the recovered DC from a CW signal could be used to operate= a switch to activate a Buzzer, light or side tone oscillator but I don't th= ink 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 r= isk of cutting a vital artery with a sharp razor blade! And no need for high= impedance cans. I rest my case for the Coherer detector.I think Edouard Branly and O= liver 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=20= working on that also. However it's very cold in my garage right now so don't= expect a result from me soon but better setup ops may have a result sooner. 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 ON7YD - OR7T At 00:42 7/01/2009, you wrote: No problem! Use MCW! Has been typical for 500 kHz. 73 DJ1ZB "M0FMT" schrieb:=20 Hi Mal and LF I am disapointed in you Mal to be considering an envelope dete= ctor. A true CW man, I would have thought, should only entertain the use of=20= a Cohere detector! Having played with them, I was surprised how well they work ov= er a range 136kc/s to 433mc/s (the extent of my power RF O/P) probably work=20= over a much 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 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 i= nfo from the web. g3kev ----- 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 E bay too On Tue, 6 Jan 2009 18:00:45 -0000 "mal hamilton" writes: Since I mentioned a Razor blade and fence wire RX a whil= e back I have had several requests for a circuit. To give others the opportu= nity to submit a cct I will await replies. This method was used successfully= at Coldiz and other POW camps to receive BBC broadcasts. Let us know how you would approach the subject. This is=20= 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 __________________________________________________________= __=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 =20 Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm for m= ore information.=20 =20 ----------------------------------------------------------------------------= -- No virus found in this incoming message. Checked by AVG - http://www.avg.com=20 Version: 8.0.176 / Virus Database: 270.10.3/1879 - Release Date: 1/6/2009=20= 5:16 PM ------=_NextPart_000_005A_01C970BA.C9E5D340 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable
Pete and co
You are wandering away from the subject. My= =20 question was not on the merits of detectors etc, simply how to build a razor= =20 blade detector and suitable earphone using scrap parts available in a trench= or=20 Jail, for instance in 1940
I have all the answers if you get stuc= k and I=20 did not get it from an internet source. Its fundamental knowl= edge=20 that a radio amateur should know and especially if the BIG BANG=20 should happen
g3kev
 
----- Original Message -----
M0FMT <= /DIV>
Sent: Wednesday, January 07, 2009 9= :35=20 AM
Subject: Re: LF: Razor blade RX ...= . Try=20 a Cohere?

 Hi Rik and LF
 
But that's the point,  an envelope detector will not detec= t CW=20 (ON / OFF Keying) unless A/ you have a local oscillator (DC rx) to=20 create a beat in the detector, added complication in design or B/ un= less=20 the carrier has got noise on it (sparker) or it is modulated, added=20 bandwidth for no extra intelligence.
 
If we go away from a simple detector RX and add amplification t= o an=20 envelope detector the recovered DC from a CW signal could be used to= =20 operate a switch to activate a Buzzer, light or side tone oscillator= =20 but I don't think thats in the spirit of the spirit of the=20 challenge.
 
However a Coherer detector does everything for CW in one simple= =20 easy to construct mechanical device with no fiddling with cats whisk= ers=20 or the risk of cutting a vital artery with a sharp razor blade! And=20= no=20 need for high impedance cans.
 
I rest my case for the Coherer detector.I think Edouard Branly and Oliver Lodge got i= t dead=20 right!
 
The challenge is to make a QSO using the Razor Blade RX I am=20 working on it. But a counter Challenge is to use a Coherer for a two= way=20 QSO, I am working on that also. However it's very cold in my garage=20 right now so don't expect a result from me soon but better setup ops= may=20 have a result sooner.
 
Regards 73 petefmt

--- On Wed, 7/1/09, Rik=20 Strobbe <rik.strobbe@fys.kuleuven.be>=20 wrote:
From:=20 Rik Strobbe <rik.strobbe@fys.kuleuven.be>
Subject: Re: LF= :=20 Razor blade RX .... Try a Cohere?
To:=20 rsgb_lf_group@blacksheep.org
Date: Wednesday, 7 January, 2009,=20= 8:11=20 AM

MCW: what a waste of bandwidth, Mal will a= llert=20 OFCOM !

73, Rik  ON7YD - OR7T

At 00:42 7/01/200= 9,=20 you wrote:
 No problem!= Use=20 MCW! Has been typical for 500 kHz.

73=20 DJ1ZB


 "M0FMT" <m0fmt@yahoo.co.uk> schrieb= :=20
Hi Mal and LF

 
I am disapointed in you Mal to be considering an envelope=20 detector. A true CW man, I would have thought, should only=20 entertain the use of a Cohere detector!

 
Having played with them, I was surprised how well they wor= k=20 over a range 136kc/s to 433mc/s (the extent of my power RF O/P= )=20 probably work over a much lager range of frequencies but not=20 tested by me.

 
http://home.ea= rthlink.net/~lenyr/coherer.htm

 
73 pefmt





 
--- On Tue, 6/1/09, mal hamilton <g3kevmal@talktalk.net= >=20 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=20 construction. Not info from the web.
g3kev

----- Original Message -----
From: riese-k3djc@juno.com
To: rsgb_lf_group@blacksheep.or= g=20
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" <<= A href=3D"mailto:g3kevmal@talktalk.net" target=3D_blank=20= rel=3Dnofollow>g3kevmal@talktalk.net> writes:
Since I mentioned a Razor blade and f= ence=20 wire RX a while back I have had several requests for a=20 circuit. To give others the opportunity to submit a cct=20= I=20 will await replies. This method was used successfully&nb= sp;=20 at Coldiz and other POW camps to receive BBC broadcasts.=
Let us know how you would approach the subject. This= is=20 applicable to MF/LF since the broadcasts at the time wer= e=20 receicved on these bands.
Build one and have a QSO using this RX
g3kev

 


 


______________________________________________________= ______=20
Fashion Design Education= - Click=20 Here!

No virus found in this incoming message.
Checked by AVG - http://www.avg.com
Version: 8.0.176 / Virus Database: 270.10.3/1877 - Rel= ease=20 Date: 1/5/2009 7:20=20 PM


 


Disclaimer: http:= //www.kuleuven.be/cwis/email_disclaimer.htm for=20 more information.=20



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