Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id x0ECcbVt022172 for ; Mon, 14 Jan 2019 13:38:38 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1gj1QB-0002Cz-Bl for rs_out_1@blacksheep.org; Mon, 14 Jan 2019 12:32:51 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1gj1Q9-0002Cq-TP for rsgb_lf_group@blacksheep.org; Mon, 14 Jan 2019 12:32:49 +0000 Received: from emout03.email.it ([212.97.34.22]) by relay1.thorcom.net with esmtp (Exim 4.89) (envelope-from ) id 1gj1Q7-0006Es-U4 for rsgb_lf_group@blacksheep.org; Mon, 14 Jan 2019 12:32:48 +0000 Received: from emout03.email.it (localhost [127.0.0.1]) by emout03.email.it (Postfix) with ESMTP id 6FFB996201 for ; Mon, 14 Jan 2019 13:32:07 +0100 (CET) Received: from x220.localnet (62-11-169-126.dialup.tiscali.it [62.11.169.126]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by emout03.email.it (Postfix) with ESMTPSA id 4D418961D1 for ; Mon, 14 Jan 2019 13:31:44 +0100 (CET) From: Claudio Pozzi To: rsgb_lf_group@blacksheep.org Date: Mon, 14 Jan 2019 13:31:34 +0100 Message-ID: <2005923.kzrCmmQryd@x220> User-Agent: KMail/4.14.1 (Linux/3.16.0-4-amd64; KDE/4.14.2; x86_64; ; ) In-Reply-To: <7C7094AC5A724A6097D0AC30B5935EBF@Clemens0811> References: <10049730.U2aOLNr8sH@x220> <7C7094AC5A724A6097D0AC30B5935EBF@Clemens0811> MIME-Version: 1.0 X-Spam-Score: -0.4 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: On Monday, January 14, 2019 12:48:04 PM you wrote: > Hi Claudio, > > >...some people can't live without the SWR meter on the > >transmission line: the harmonics not irradiated return toward > >the Tx [...] Content analysis details: (-0.4 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [212.97.34.22 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.2 FREEMAIL_ENVFROM_END_DIGIT Envelope-from freemail username ends in digit (smtp01[at]email.it) 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (smtp01[at]email.it) 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: 4f449c45f7b1894a9195a328eedaeb30 Subject: Re: LF: Low Pass Filtering Content-Type: multipart/alternative; boundary="nextPart8550983.nGEbCRt9iz" Content-Transfer-Encoding: 7Bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=1.0 required=5.0 tests=FROM_ENDS_IN_NUMS,HTML_60_70, 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 This is a multi-part message in MIME format. --nextPart8550983.nGEbCRt9iz Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" On Monday, January 14, 2019 12:48:04 PM you wrote: > Hi Claudio, > > >...some people can't live without the SWR meter on the > >transmission line: the harmonics not irradiated return toward > >the Tx and the SWR meter show an high value: terrible!!! > > > >but if you have a LPF the SWR is also high BEFORE the filter > > If you have the usual configuration TX->LPF->SWR_Meter->Antenna > the indicated SWR will NOT be spoiled by returning harmonics because > they are attenuated by the LPF and reflected into the TX. > So only extremely weak harmonics make it to the antenna. > Their refeflection by the antenna does'nt change SWR measurably. Yes Clemens, I agree. I mean that without the LPF the SWR meter measure all the harmonics reflected by the antenna, so the SWR measured can be a lot higher and can be cause of MOSFETS failure. I come from vacuum tube Tx and I can survive with high SWR if also the transmitter can ;-) 73 Claudio, IK2PII -- ZE-Light e ZE-Pro: servizi zimbra per caselle con dominio email.it, per tutti i dettagli Clicca qui http://posta.email.it/caselle-di-posta-z-email-it.php?utm_campaign=email_Zimbra_102014=main_footer/f Sponsor: Idee regalo classiche o alternative? Trova l'offerta migliore in un click Clicca qui: http://adv.email.it/cgi-bin/foclick.cgi?mid=13327&d=14-1 --nextPart8550983.nGEbCRt9iz Content-Transfer-Encoding: 7Bit Content-Type: text/html; charset="us-ascii"

On Monday, January 14, 2019 12:48:04 PM you wrote:

> Hi Claudio,

>

> >...some people can't live without the SWR meter on the

> >transmission line: the harmonics not irradiated return toward

> >the Tx and the SWR meter show an high value: terrible!!!

> >

> >but if you have a LPF the SWR is also high BEFORE the filter

>

> If you have the usual configuration TX->LPF->SWR_Meter->Antenna

> the indicated SWR will NOT be spoiled by returning harmonics because

> they are attenuated by the LPF and reflected into the TX.

> So only extremely weak harmonics make it to the antenna.

> Their refeflection by the antenna does'nt change SWR measurably.

 

Yes Clemens, I agree.

 

I mean that without the LPF the SWR meter measure all the harmonics reflected by the antenna, so the SWR measured can be a lot higher and can be cause of MOSFETS failure.

 

I come from vacuum tube Tx and I can survive with high SWR if also the transmitter can ;-)

 

73

Claudio, IK2PII

 

 




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