Return-Path: Received: from mtain-mh07.r1000.mx.aol.com (mtain-mh07.r1000.mx.aol.com [172.29.96.219]) by air-me01.mail.aol.com (v127_r1.1) with ESMTP id MAILINME011-8ba04b9039a129c; Thu, 04 Mar 2010 17:52:17 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mh07.r1000.mx.aol.com (Internet Inbound) with ESMTP id 9C5C7380000BB; Thu, 4 Mar 2010 17:52:15 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NnJsp-0002zN-LI for rs_out_1@blacksheep.org; Thu, 04 Mar 2010 22:51:07 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NnJso-0002zE-VG for rsgb_lf_group@blacksheep.org; Thu, 04 Mar 2010 22:51:06 +0000 Received: from web28101.mail.ukl.yahoo.com ([217.146.182.121]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1NnJso-0002oI-Py for rsgb_lf_group@blacksheep.org; Thu, 04 Mar 2010 22:51:06 +0000 Received: (qmail 15921 invoked by uid 60001); 4 Mar 2010 22:51:00 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.co.uk; s=s1024; t=1267743060; bh=6+jgSgMdUcwYGBazKse9NVrE4JfzwwF3wtyLGi82Z+k=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=ozkMat3jTN2Czvl0fjb8W1vZPPM1igxHi62qWLG+APnlpaSr7iH8gn9JJPKitHg3sT8O+AQcdVTWcbrCRw+dNQ8FPsg4NmteOdjnqt381HtgsUe9JSsh14ogZl345r9x4vjRqUj1/01yc7CIFR/Q6P2HUDm2egLI4gqS2MTziqI= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.co.uk; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=zj6UQ8Zy++kAyAQs7nmQUMzhPr8jwXZd9n2yjT/J9cJl2OGESIHzbHpssQpKr6AJdOvCrpMEnJDeixOgMwmcEtivvYtecLciQJAcYrYuzqoji3hpd7L1UHeSbJbWTHq/5JGUc7j3XG3F+6Dnx881UdKv/1c08Pv5kHuPcRgiOE8=; Message-ID: <754354.15151.qm@web28101.mail.ukl.yahoo.com> X-YMail-OSG: nEzAAGUVM1luwjzKbRRDDQbAhA38C2U3ytzj1couJhjPgMZuK95WrHYf1ipWRsnEO_OTAaKo63fkk7KjfyXVSKmYzIwPu_DeCzAj1qYf5pexzgwJBXCDjXXmekPUfa5D1AA.fEbY_.ZHZxRuNX75Hg.0YZGZ.171AubMpKyXxyePx0JY6IgNduPmdK6AW1ZiVGC4nbV1A37DCWpuDtwUSiVi1738p8gVX181JSiYGfVGRbSBt287n_YjLlHdey.kKPlabVPvG6iouPb3ANBYB8W8RHE- Received: from [86.143.244.65] by web28101.mail.ukl.yahoo.com via HTTP; Thu, 04 Mar 2010 22:51:00 GMT X-Mailer: YahooMailClassic/9.2.12 YahooMailWebService/0.8.100.260964 Date: Thu, 4 Mar 2010 22:51:00 +0000 (GMT) From: M0FMT To: rsgb_lf_group@blacksheep.org In-Reply-To: <0E8B88C624C64C22B6B981E80B2F6B66@IBM7FFA209F07C> MIME-Version: 1.0 DomainKey-Status: good (testing) Subject: Re: LF: 9kHz: soundcard RX Content-Type: multipart/alternative; boundary="0-364591396-1267743060=:15151" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.2 required=5.0 tests=CELL_PHONE_BOOST,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-AUTHENTICATION: mail_rly_antispam_dkim-d272.2 ; domain : yahoo.co.uk DKIM : pass x-aol-sid: 3039ac1d60db4b90399f5d31 X-AOL-IP: 193.82.116.20 --0-364591396-1267743060=:15151 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable If I have understood the issue, it=A0is that you are saying sound cards ar= e very venerable to damage when fed with an external antenna to the mic so= cket? If that is the assertion then I am say that I have had a good survival rat= e when doing just that over a relatively long period of time. Also other= pieces of kit are connected to=A0antennas like very very expensive=A0tran= sceivers and modems connected to antenna like telephone wires... there is= potential hazard to all these devices. So we do take a risk when connecti= ng any sensitive electronic device to an external antenna but the risk can= be mitigated by ensuring the antenna is removed when not in use and espec= ially during lightning storms and / or by adding some form of static bypas= s arrangement. And yes a pair of back to back=A0diodes appear to prevent= damage because of their voltage limiting characteristic. It is a precauti= on=A0I would recommend as a minimum protection but you can never be sure= how well they would actually work. Its a risking business play with high= external antennas but that's what we do. =A0 That is my point and nothing else.=A0 73 es GL petefmt --- On Thu, 4/3/10, Chris wrote: From: Chris Subject: Re: LF: 9kHz: soundcard RX To: rsgb_lf_group@blacksheep.org Date: Thursday, 4 March, 2010, 16:25 Not sure what your point is, surely you're just saying the diodes are doin= g their job? Chris, G4AYT. ----- Original Message -----=20 From: M0FMT=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, March 04, 2010 7:07 AM Subject: Re: LF: 9kHz: soundcard RX never blown a sound card up yet in over almost ten years of use. Two back= to back diodes on the antenna lead close to the input plug. Don't leave= it connected during thunderstorms. Most modems are left connected day and= night to very very long over head telephone wires for years with out prob= lems. Vastly over hyped problem. 73 es GL petefmt --- On Wed, 3/3/10, Horst St=F6cker wrote: From: Horst St=F6cker Subject: LF: 9kHz: soundcard RX To: rsgb_lf_group@blacksheep.org Date: Wednesday, 3 March, 2010, 9:32 >And what about a simple band pass filter to supress the 50Hz and it's har= monics? Necessary or dispensable? You can hear (!) the difference. I just took a 10mH coil from Reichelt to= improve my soundcard-RX before one of the last SAQ activities. Despite of more or less excellent digital filtering of SpecLab it's a good= idea. One should not keep the soundcard busy with unwanted signals. What I am not sure about is the use of an audio transformer. It might have= some influence to the signal. As it just has to keep the soundcard from= beeing blown it might be a good idea to take a cheap soundcard instead of= the audio transformer - and maybe a second in spare. Stefan, what USB-soundcard you bought for 10 EUR ? Horst DO1KHS ___________________________________________________________ GRATIS f=FCr alle WEB.DE-Nutzer: Die maxdome Movie-FLAT! Jetzt freischalten unter http://movieflat.web.de =20 --0-364591396-1267743060=:15151 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
If I have understood the issue, it&nbs= p;is that you are saying sound cards are very venerable to damage when fed= with an external antenna to the mic socket?
If that is the assertion then I am say that I have had a good surviva= l rate when doing just that over a relatively long period of time. Also ot= her pieces of kit are connected to antennas like very very expensive&= nbsp;transceivers and modems connected to antenna like telephone wires...= there is potential hazard to all these devices. So we do take a risk when= connecting any sensitive electronic device to an external antenna but the= risk can be mitigated by ensuring the antenna is removed when not in use= and especially during lightning storms and / or by adding some form of st= atic bypass arrangement. And yes a pair of back to back diodes appear= to prevent damage because of their voltage limiting characteristic. It is= a precaution I would recommend as a minimum protection but you can= never be sure how well they would actually work. Its a risking business= play with high external antennas but that's what we do.
 
That is my point and nothing else. 

73 es GL= petefmt

--- On Thu, 4/3/10, Chris <c.ashby435@btinternet.= com> wrote:

From: Chris <c.ashby435@btinternet.com><= BR>Subject: Re: LF: 9kHz: soundcard RX
To: rsgb_lf_group@blacksheep.org=
Date: Thursday, 4 March, 2010, 16:25

Not sure what your point is, surely you'r= e just saying the diodes are doing their job?
Chris, G4AYT.
----- Original Message -----
From: M0FMT
Sent: Thursday, March 04, 2010 7:07= AM
Subject: Re: LF: 9kHz: soundcard RX=

never blown a sound card up yet in over almost ten years= of use. Two back to back diodes on the antenna lead close to the input pl= ug. Don't leave it connected during thunderstorms. Most modems are left co= nnected day and night to very very long over head telephone wires for year= s with out problems. Vastly over hyped problem.

73 es GL petefmt
--- On Wed, 3/3/10, Horst St=F6cker <horst.stoecker@web.de&g= t; wrote:

From: Horst St=F6cker <horst.stoecker@web.d= e>
Subject: LF: 9kHz: soundcard RX
To: rsgb_lf_group@blacksheep.o= rg
Date: Wednesday, 3 March, 2010, 9:32

>And what about a simple band pass filter to sup= ress the 50Hz and it's harmonics? Necessary or dispensable?

You can= hear (!) the difference. I just took a 10mH coil from Reichelt to improve= my soundcard-RX before one of the last SAQ activities.

Despite of= more or less excellent digital filtering of SpecLab it's a good idea. One= should not keep the soundcard busy with unwanted signals.

What I= am not sure about is the use of an audio transformer. It might have some= influence to the signal. As it just has to keep the soundcard from beeing= blown it might be a good idea to take a cheap soundcard instead of the au= dio transformer - and maybe a second in spare.

Stefan, what USB-sou= ndcard you bought for 10 EUR ?

Horst DO1KHS
____________________= _______________________________________
GRATIS f=FCr alle WEB.DE-Nutzer= : Die maxdome Movie-FLAT!
Jetzt freischalten unter http://movieflat.web.de<= /A>


<= /DIV>

=20 --0-364591396-1267743060=:15151--