Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-1.8 required=5.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED, RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: : mailn 1480; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v5NIDHdO024785 for ; Fri, 23 Jun 2017 20:13:18 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1dOSvy-0003rN-K0 for rs_out_1@blacksheep.org; Fri, 23 Jun 2017 19:03:54 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1dOSvy-0003rE-9i for rsgb_lf_group@blacksheep.org; Fri, 23 Jun 2017 19:03:54 +0100 Received: from smtp1web.tin.it ([212.216.176.195]) by relay1.thorcom.net with esmtp (Exim 4.89) (envelope-from ) id 1dOSvv-0008Ic-CF for rsgb_lf_group@blacksheep.org; Fri, 23 Jun 2017 19:03:52 +0100 Received: from feu5 (10.192.64.15) by smtp1web.tin.it (8.6.060.43) id 58893FFA02FAA008 for rsgb_lf_group@blacksheep.org; Fri, 23 Jun 2017 20:03:49 +0200 Received: from (80.180.102.8) by wmlighttin.pc.tim.it; Fri, 23 Jun 2017 20:03:49 +0200 Message-ID: <15cd61fd613.marcocadeddu@tin.it> Date: Fri, 23 Jun 2017 20:03:49 +0200 (CEST) From: "marcocadeddu@tin.it" To: Mime-Version: 1.0 X-Originating-IP: 80.180.102.8 X-Scan-Signature: 49f0f587e44d6711c57b8a4e950ba850 Subject: R: LF: Transformer questions. Content-Type: text/plain;charset="UTF-8" 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 2.75 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by lipkowski.org id v5NIDHdO024785 Status: O X-Status: X-Keywords: X-UID: 12073 Hello Chris, probably the other LFers are around to have a fresh bier :-) today here +40°C... I don't know (or remember..) which kind of antenna are you using: how much the impedance changes with the other conditions have you huge change of impedance? have you a variometer in place? In my case from rainy to dry weather I have more detuning than change of impedance and the variometer is enough for these adjuments. I have also a separation/matching transformer in line but it was adjusted after resonating the antenna (it matches the few tens of ohms to 50 ohms value). If you need really to match the impedance you could install a transformer with more taps, but remember to not switch during transmission!! my matching separating transformer is made on 2 stacked FT240-43 cores with 20 turns on the 50 ohm side. Marco, IK1HSS ----Messaggio originale---- Da: dead.fets@gmail.com Data: 23-giu-2017 14.03 A: Ogg: LF: Transformer questions. Hello LF'ers, Two 500 watt Class D amps combined. The output transformer of the combiner is now an auto transformer. This feeds, via RG-213 to outdoors, where an isolating transformer, that is a conventional primary / secondary transformer with taps for impedance matching then feeds my loading coil and then the antenna. Can I wind the isolating transformer as a 1 : 1 and do impedance matching (which changes with weather / foliage growth) indoors using a tapped combiner auto transformer? I want to change the impedance matching / isolating transformer anyway as it runs a bit hot on long TX sequences. I tried an auto trans former as the impedance matching one outside, but had serious RF into the mains causing various issues, a conventional isolating / impedance transformer fixed all that, so I assume it needs to stay, even as a 1 :1 ? Thanks. -- Best regards, Chris mailto:dead.fets@gmail.com