Return-Path: Received: (qmail 52606 invoked from network); 30 Dec 2003 18:19:22 -0000 Received: from unknown (HELO ptb-mxscan01.plus.net) (212.159.14.235) by ptb-mailstore01.plus.net with SMTP; 30 Dec 2003 18:19:22 -0000 Received: (qmail 4688 invoked from network); 30 Dec 2003 18:19:22 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Priority: 3 X-MSMail-Priority: Normal X-Spam-detection-level: 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from ptb-mxcore01.plus.net (212.159.14.215) by ptb-mxscan01.plus.net with SMTP; 30 Dec 2003 18:19:21 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim) id 1AbOSf-00016q-7L for dave@picks.force9.co.uk; Tue, 30 Dec 2003 18:19:21 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AbORo-0000wL-UX for rs_out@blacksheep.org; Tue, 30 Dec 2003 18:18:28 +0000 Received: from [217.72.192.165] (helo=mailgate5.cinetic.de) by post.thorcom.com with esmtp (Exim 4.14) id 1AbORo-0000wC-AP for rsgb_lf_group@blacksheep.org; Tue, 30 Dec 2003 18:18:28 +0000 Received: from web.de (fmomail03.dlan.cinetic.de [172.20.1.236]) by mailgate5.cinetic.de (8.11.6p2/8.11.2/SuSE Linux 8.11.0-0.4) with SMTP id hBUIHvQ11107 for rsgb_lf_group@blacksheep.org; Tue, 30 Dec 2003 19:17:57 +0100 Date: Tue, 30 Dec 2003 19:17:57 +0100 Message-ID: <200312301817.hBUIHvQ11107@mailgate5.cinetic.de> MIME-Version: 1.0 Organization: http://freemail.web.de/ From: "Hans-Albrecht Haffa" To: rsgb_lf_group@blacksheep.org Subject: LF: TR-Switch for new TX Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on post.thorcom.com X-Spam-Status: No, hits=0.1 required=5.0 tests=HTML_MESSAGE,MIME_HTML_ONLY autolearn=no version=2.60 X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-PN-SPAMFiltered: yes X-Spam-Rating: 1

Dear Lowfers,
just I am designing a TR-switch for my new TX. Estimated Power about 60dbm/60 Ohm.
The current situation with my TX 70W/60 Ohm:

The RX-Path is swiched via two reed-Relays (homemade coaxial ones, for qsk operation) to the receiver input, the TX-Path is switched via a reed-relay to the PA both from the common input of low-pass-filter, whitch is allways in the aerial path. My RX is an EKD 300 (Funkwerk Köpenick, late DDR). In transmit operation this will cause an sidetone with an pretty high volume, but not too much annoying noisy.

My experiments with an 1 Watt driver circuit:

The signal Path: Oscillator - Driver 1 Watt - Attenuator switchable 0d B...50 dB - TR-relays - RX-Input

TR-relays is a series of one Vac-Relay and three Reed-Relays (2 spst, 1 spdt).

All build up with coax connectors. It seems to be that I am still far away from a S9 signal durig transmitting, even with this 1 Watt-Driver.
How You have solved this task? What is done in commercial equipment with similar power?
Is it necesary to have anyway a mute circuit for the receiver? An input voltage of 1 Volt will not be dangerous for the RX-input and cause some distortionin the audio-signal, but for a sidetone this is not a problem.
Waiting for reply

55,

Hans-Albrecht Haffa

DK 8 ND

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