Return-Path: X-Spam-DCC: paranoid 1182; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.5 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_50_60,HTML_MESSAGE,RATWARE_GECKO_BUILD,SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u9EFBCNj031573 for ; Fri, 14 Oct 2016 17:11:16 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1bv2Da-0002jF-Oe for rs_out_1@blacksheep.org; Fri, 14 Oct 2016 14:08:10 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1bv2Da-0002j6-67 for rsgb_lf_group@blacksheep.org; Fri, 14 Oct 2016 14:08:10 +0100 Received: from smtpout.karoo.kcom.com ([212.50.160.34]) by relay1.thorcom.net with esmtp (Exim 4.87) (envelope-from ) id 1bv2DW-0006KN-Uh for rsgb_lf_group@blacksheep.org; Fri, 14 Oct 2016 14:08:09 +0100 X-IronPort-AV: E=Sophos;i="5.31,493,1473116400"; d="scan'208,217";a="124059283" Received: from unknown (HELO [127.0.0.1]) ([109.176.246.47]) by smtpout.karoo.kcom.com with ESMTP; 14 Oct 2016 14:08:02 +0100 Message-ID: <5800D853.2060304@lineone.net> Date: Fri, 14 Oct 2016 14:06:27 +0100 From: LineOne User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:31.0) Gecko/20100101 Thunderbird/31.1.2 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <57FD3F9F.80409@lineone.net> <3018579.iHz3xfyXX4@x220> <57FE86C5.3080408@lineone.net> <57FE889A.5020605@posteo.de> In-Reply-To: <57FE889A.5020605@posteo.de> X-Scan-Signature: eb65b97b00a71049be1fa526941c7b31 Subject: Re: LF: Audio link Content-Type: multipart/alternative; boundary="------------080407020509060505010805" 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.11 Content-Length: 7913 Status: O X-Status: X-Keywords: X-UID: 9076 This is a multi-part message in MIME format. --------------080407020509060505010805 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Hello Stefan. The QRM is direct from the circuits in the computer, having a cast alloy frame, grounding it helps tremendously most of the time. What I will do is to feed the balanced 300ohm radio antenna input terminals from some twin screened RF cable I have and run it out though the rear wall of the shack, this being a grounded steel panel, and back in just far enough to pick up the antenna terminals. Having to use the large horizontal loop antenna in an inverted-L configuration for LF and MF doesn't help but I have no choice. 73, Hugh, M0DSZ On 12/10/2016 20:01, DK7FC wrote: > Hi Hugh, > > But then the problem should be solved when placing the isolation audio > transformer on the laptops end, so the wire does not act as an > antenna. Did you try that? > Maybe grounding the laptop to the mains earth is another idea, but > only when using the audio transformer. > > 73, Stefan > > Am 12.10.2016 20:53, schrieb LineOne: >> Hello Claudio. >> >> Any combination of grounding wire, or no wire, makes no difference, >> the QRM is directly radiated. If you see my "shack" there's just >> enough room to sit by the desk so I can't rearrange equipment any >> better. "Cosy" would be a nice description. >> The laptop is usually OK but it is charged by time switch about every >> 2.5 hours and when fully charged, if the timer is still, on it can >> wipe 10 to 20dB s/n off the signal in spite of having a linear charger. >> >> 73, Hugh, M0DSZ >> >> On 12/10/2016 15:37, Claudio Pozzi wrote: >>> >>> On Tuesday 11 October 2016 20:38:07 you wrote: >>> >>> > To avoid having laptop running in the shack, which occasionally >>> >>> > produces some QRM, I can send received audio from the shack to a >>> >>> > desktop computer in the house on a twisted telephone pair. This works >>> >>> > but any wire connection between shack and this desktop introduces some >>> >>> > spurious signals on 136khz even if I use an audio isolating >>> transformer. >>> >>> > >>> >>> The AC 230 power supply in the shack and the desktop computer >>> grounding wire are equipotential, share the same grounding system? >>> >>> 73 de Claudio ik2pii >>> >>> >>> >>> >>> ---- >>> ZE-Light e ZE-Pro: servizi zimbra per caselle con dominio email.it, >>> per tutti i dettagli clicca qui >>> >>> >>> Sponsor: >>> Registra i domini che desideri ed inizia a creare il tuo sito web >>> Clicca qui >>> >> --------------080407020509060505010805 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: 8bit Hello Stefan.

The QRM is direct from the circuits in the computer, having a cast alloy frame, grounding it helps tremendously most of the time. What I will do is to feed the balanced 300ohm radio antenna input terminals from some twin screened RF cable I have and run it out though the rear wall of the shack, this being a grounded steel panel, and back in just far enough to pick up the antenna terminals. Having to use the large horizontal loop antenna in an inverted-L configuration for LF and MF doesn't help but I have no choice.

73, Hugh, M0DSZ

On 12/10/2016 20:01, DK7FC wrote:
Hi Hugh,

But then the problem should be solved when placing the isolation audio transformer on the laptops end, so the wire does not act as an antenna. Did you try that?
Maybe grounding the laptop to the mains earth is another idea, but only when using the audio transformer.

73, Stefan

Am 12.10.2016 20:53, schrieb LineOne:
Hello Claudio.

Any combination of grounding wire, or no wire, makes no difference, the QRM is directly radiated. If you see my "shack" there's just enough room to sit by the desk so I can't rearrange equipment any better.  "Cosy" would be a nice description.
The laptop is usually OK but it is charged by time switch about every 2.5 hours and when fully charged, if the timer is still, on it can wipe 10 to 20dB s/n off the signal in spite of having a linear charger.

73, Hugh, M0DSZ

On 12/10/2016 15:37, Claudio Pozzi wrote:

On Tuesday 11 October 2016 20:38:07 you wrote:

> To avoid having laptop running in the shack, which occasionally

> produces some QRM, I can send received audio from the shack to a

> desktop computer in the house on a twisted telephone pair. This works

> but any wire connection between shack and this desktop introduces some

> spurious signals on 136khz even if I use an audio isolating transformer.

>

 

The AC 230 power supply in the shack and the desktop computer grounding wire are equipotential, share the same grounding system?

 

73 de Claudio ik2pii

 

 




----
ZE-Light e ZE-Pro: servizi zimbra per caselle con dominio email.it, per tutti i dettagli clicca qui

Sponsor:
Registra i domini che desideri ed inizia a creare il tuo sito web
Clicca qui



--------------080407020509060505010805--