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 wALGp5Qb002409 for ; Wed, 21 Nov 2018 17:51:11 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1gPVae-0006V4-9H for rs_out_1@blacksheep.org; Wed, 21 Nov 2018 16:43:00 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1gPVad-0006Uv-Vq for rsgb_lf_group@blacksheep.org; Wed, 21 Nov 2018 16:42:59 +0000 Received: from mail-ed1-x52b.google.com ([2a00:1450:4864:20::52b]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1gPVab-0002aP-I1 for rsgb_lf_group@blacksheep.org; Wed, 21 Nov 2018 16:42:58 +0000 Received: by mail-ed1-x52b.google.com with SMTP id d3so5406252edx.7 for ; Wed, 21 Nov 2018 08:42:57 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=XjveMTfhmuDiBJ9nzU4V2ECouUwnCFl2jb2wkPATkWA=; b=EmD7rydBxa4xPMkqJnzzhYfGw57VVOlCPyqJRxGsKvpP596j+nCcScutmIB4yuyPdt xvLT5dxxlLgp5lWCY82UkRfktV+swyxiuvDSHaJJdjUA2js9qivHrHkHFZ843Ha3GYng 2nHp4SaZ34AUcxbYvvySjR/0cRVb1oi6Vt/Yv1OwHFLocIdg6x1TocH5Yrr4hATpr/4t dXK4t6IcXCvCsKGUB1JgjaTy2sgfEjQAqbKI8IPg+aTKqDmPX/Pn2oDuRA1tXd5rG8dv HaQ8q9ftpjVyPUdqgvu59bL7pAxLAhHk4ELGTLTmrLg6ItL1l8C2cXEeI1jlo8/K5ZEj OtOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=XjveMTfhmuDiBJ9nzU4V2ECouUwnCFl2jb2wkPATkWA=; b=RDWOKGRf9qBIW9OG6/htwk7/bFV3/qcylBbzeP83dSga4q62XZl4MnO4HMwmVKtDun v+338EmBEzqjT8LLdVNRABOTfiU5fs4ybErS4F5BSEQt5vnfc2YqcAJlF5QH47lfjN4A 4SEtkKzgG4zp77GP5fZAWmMIT7sbtFxzs34Hb5FPbEi3gkBScIbOJCXqRG9484tHrob0 aX9DYS/b8W0zpp1VLzsVDqkqfTFXbDj4398B7nM5YdgBn/QigIq3lgnj2fD5tCdCWKeR m9/CSnmtGntHsBsJNQ/hf0cARAav4XGQvBOKOQnpRqnEgGvYSu2sbrvYNcxqKG1I5sWf +GNQ== X-Gm-Message-State: AA+aEWbsjEiCPIXlX/xNFouZT9KqUVl7rhJ9zg/9snpPcswKekK+XhIw nG7cDeRfYvjDJPMH1P0Sv41CMXqVTHpmA21fow4zm3yP X-Google-Smtp-Source: AFSGD/UO2asC6A56iAzewe/dV0gu0LMy8bhQsEB8cUGMyHI8/OWlMWZx05xxv4M7ATAl9oqoc8OCMJ9Mqz1PP9W53oU= X-Received: by 2002:a50:9784:: with SMTP id e4mr6247889edb.165.1542818576617; Wed, 21 Nov 2018 08:42:56 -0800 (PST) MIME-Version: 1.0 From: Andy Talbot Date: Wed, 21 Nov 2018 16:42:45 +0000 Message-ID: To: rsgb_lf_group , "rsgb_lf_group@blacksheep.org" X-Spam-Score: 0.0 (/) 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: I got an answer from the design team at Elad, including a circuit of the receiver front end, and it looks safe enough. On receiver a PE4283 solid state relay places a short circuit across the transformer feeding the A/D chip. There is also a BAR66 clamp diode at this point, clamping to ~ 1.2V pk-pk max. The BAR66 is a [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [2a00:1450:4864:20:0:0:0:52b listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (andy.g4jnt[at]gmail.com) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 195b836cb7437e99aa05107459888659 Subject: LF: Re: Elad FDM-DUO on LF Content-Type: multipart/alternative; boundary="00000000000036561b057b2f71bf" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_40_50,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 --00000000000036561b057b2f71bf Content-Type: text/plain; charset="UTF-8" I got an answer from the design team at Elad, including a circuit of the receiver front end, and it looks safe enough. On receiver a PE4283 solid state relay places a short circuit across the transformer feeding the A/D chip. There is also a BAR66 clamp diode at this point, clamping to ~ 1.2V pk-pk max. The BAR66 is a high peak current surge protection device with maximum 1.8 ohm forward resistance at 100MHz, 5mA https://www.mouser.com/ds/2/196/bar66series-87696.pdf If using the Rx-2 ant input, there is an additional BAR66 on this. I'd still be happier seeing circuitry that specifically opens the Rx path to the A/D when on transmit, but those clamps and the switched short look good enough. (And the fact teh BAR device is rated to 100MHz suggests its OK for protection at high VHF back-leakage too). Andy www.g4jnt.com --00000000000036561b057b2f71bf Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I got an answer from the design= team at Elad, including a circuit of the receiver front end, and it looks = safe enough.

On receiver a PE4283 solid = state relay places a short circuit across the transformer feeding the A/D c= hip.=C2=A0 =C2=A0There is also a BAR66 clamp diode at this point, clamping = to ~ 1.2V pk-pk max.=C2=A0 The BAR66 is a=C2=A0 high peak current surge pro= tection device with maximum 1.8 ohm forward resistance at 100MHz, 5mA
=
https://www.mouser.co= m/ds/2/196/bar66series-87696.pdf

If using the Rx-2 ant input, there is an additional BAR66 on this.<= /div>

I'd still be happier seeing circuitr= y that specifically opens the Rx path to the A/D when on transmit, but thos= e clamps and the switched short look good enough. (And the fact teh BAR dev= ice is rated to 100MHz suggests its OK for protection at high VHF back-leak= age too).

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