Return-Path: X-Spam-DCC: paranoid 1233; 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=-0.7 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_MESSAGE,RATWARE_GECKO_BUILD 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 tB4CoXtH011888 for ; Fri, 4 Dec 2015 13:50:33 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1a4pkx-0000sV-Cl for rs_out_1@blacksheep.org; Fri, 04 Dec 2015 12:46:35 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1a4pkx-0000sM-2h for rsgb_lf_group@blacksheep.org; Fri, 04 Dec 2015 12:46:35 +0000 Received: from smtpout.karoo.kcom.com ([212.50.160.34]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1a4pjs-0008KX-Qe for rsgb_lf_group@blacksheep.org; Fri, 04 Dec 2015 12:46:33 +0000 X-IronPort-AV: E=Sophos;i="5.20,380,1444690800"; d="scan'208,217";a="146792748" Received: from unknown (HELO [127.0.0.1]) ([82.153.122.51]) by smtpout.karoo.kcom.com with ESMTP; 04 Dec 2015 12:45:11 +0000 Message-ID: <56618AD6.8070205@lineone.net> Date: Fri, 04 Dec 2015 12:45:10 +0000 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: <565D78F1.5060106@lineone.net> <3061063.yGTG6Xp9uk@zv5000> In-Reply-To: <3061063.yGTG6Xp9uk@zv5000> X-Scan-Signature: 7ee575a0a6578bbbbe5ea7af32688fd5 Subject: Re: LF: Beware damage from active antennas Content-Type: multipart/alternative; boundary="------------020702070701090803010809" 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 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 5541 This is a multi-part message in MIME format. --------------020702070701090803010809 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit I assume that as this is high impedance and tiny current into the amplifier that ferrite beads may not be quite so so effective. I do like them though, cheap and easy, removable with no damage. If your whip setup is wide-band, would a low-pass filter be appropriate, or if single band, how about a series-tuned circuit? These should take the edge off any spikes. Hugh, M0DSZ On 03/12/2015 16:29, Claudio Pozzi wrote: > > On Tuesday, December 01, 2015 11:23:09 you wrote: > > > Yes, there are plenty of options for normal Tx/Rx. In fact the > > > existing C/O relay in the 137 transmitter provides more than enough > > > isolation for that > > > > > > But I was on a separate active whip at the time, a quite independent > > > conenction and irrelevent to real operation at the time. It was the > > > fact that the active whip could shove out such an alarmingly high > > > level that concerned me - 13V very sharp spikes. And I forgot to > > > mention in the previous post, those 13V edge spikes went to both +13V > > > and -13V, so technically 26Vp-p > > > > > > Perhaps the homebrew designs others use aren't so robust in their output > > > stages? > > > > > For sharp spikes coming out from the cable I suggest some ferrite bead > or a VK200 choke on the receiver input. I believe they have no > attenuation at LF frequency. > > 73 de Claudio ik2pii > > -- > > Claudio Pozzi - rispondere a cla.po@tiscali.it > > > > > ---- > ZE-Light e ZE-Pro: servizi zimbra per caselle con dominio email.it, > per tutti i dettagli clicca qui > > > Sponsor: > Soluzioni di email hosting per tutte le esigenze: dalle caselle > gratuite a quelle professionali su piattaforma Zimbra, da quelle su > proprio dominio a quelle certificate PEC. Confronta le soluzioni > Clicca qui > --------------020702070701090803010809 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: 8bit I assume that as this is high impedance and tiny current into the amplifier that ferrite beads may not be quite so so effective. I do like them though, cheap and easy, removable with no damage.
If your whip setup is wide-band, would a low-pass filter be appropriate, or if single band, how about a series-tuned circuit? These should take the edge off any spikes.

Hugh, M0DSZ

On 03/12/2015 16:29, Claudio Pozzi wrote:

On Tuesday, December 01, 2015 11:23:09 you wrote:

> Yes, there are plenty of options for normal Tx/Rx. In fact the

> existing C/O relay in the 137 transmitter provides more than enough

> isolation for that

>

> But I was on a separate active whip at the time, a quite independent

> conenction and irrelevent to real operation at the time. It was the

> fact that the active whip could shove out such an alarmingly high

> level that concerned me - 13V very sharp spikes. And I forgot to

> mention in the previous post, those 13V edge spikes went to both +13V

> and -13V, so technically 26Vp-p

>

> Perhaps the homebrew designs others use aren't so robust in their output

> stages?

>

 

For sharp spikes coming out from the cable I suggest some ferrite bead or a VK200 choke on the receiver input. I believe they have no attenuation at LF frequency.

 

73 de Claudio ik2pii

 

--

Claudio Pozzi - rispondere a cla.po@tiscali.it

 

 




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