<html><head></head><body><div style="color:#000; background-color:#fff; font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:13px"><div id="yui_3_16_0_1_1470577691523_15451"><span>Rob,</span></div><div id="yui_3_16_0_1_1470577691523_15455" dir="ltr"><span id="yui_3_16_0_1_1470577691523_15454">The offset has to do with the carrier generation, modulator and the filter arrangement. Working from my HW101 schematics, the balanced modulator produces both sidebands and nulls out the carrier (3395.000kHz). For the upper sideband, there is no offset and the double sideband audio passes through the crystal filter with the "carrier" on the high side of the audio. The filter is 2.1kHz wide so only audio gets through and any remaining carrier is nulled out. The sideband is reversed later in the radio. <br></span></div><div id="yui_3_16_0_1_1470577691523_15866" dir="ltr"><span id="yui_3_16_0_1_1470577691523_15454">In lower sideband, the carrier is offset about 2.8kHz which then sends the audio through the filter with the carrier below the audio. Again whatever carrier remains is also attenuated by the filter. The lower sideband is reversed in the later stages of the radio. <br></span></div><div id="yui_3_16_0_1_1470577691523_16081" dir="ltr"><span id="yui_3_16_0_1_1470577691523_15454">In this way, only one audio filter is needed for all modes of the transmitter, CW included. All stages following the modulator are then linear, including the finals which are running AB1.</span></div> <div class="qtdSeparateBR"><br><br></div><div style="display: block;" class="yahoo_quoted"> <div style="font-family: Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 13px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"><font face="Arial" size="2"> On Thursday, August 4, 2016 11:00 AM, "heath-request@puck.nether.net" <heath-request@puck.nether.net> wrote:<br></font></div> <br><br> <div class="y_msg_container">Send Heath mailing list submissions to<br> <a ymailto="mailto:heath@puck.nether.net" href="mailto:heath@puck.nether.net">heath@puck.nether.net</a><br><br>To subscribe or unsubscribe via the World Wide Web, visit<br> <a href="https://puck.nether.net/mailman/listinfo/heath" target="_blank">https://puck.nether.net/mailman/listinfo/heath</a><br>or, via email, send a message with subject or body 'help' to<br> <a ymailto="mailto:heath-request@puck.nether.net" href="mailto:heath-request@puck.nether.net">heath-request@puck.nether.net</a><br><br>You can reach the person managing the list at<br> <a ymailto="mailto:heath-owner@puck.nether.net" href="mailto:heath-owner@puck.nether.net">heath-owner@puck.nether.net</a><br><br>When replying, please edit your Subject line so it is more specific<br>than "Re: Contents of Heath digest..."<br><br><br>Today's Topics:<br><br> 1. Re: SB-401 / SB-303 LMO question (Robert Myers)<br><br><br>----------------------------------------------------------------------<br><br>Message: 1<br>Date: Thu, 4 Aug 2016 03:34:17 -0400<br>From: "Robert Myers" <<a ymailto="mailto:rsmyers@rogers.com" href="mailto:rsmyers@rogers.com">rsmyers@rogers.com</a>><br>To: <<a ymailto="mailto:heathkit@yahoogroups.com" href="mailto:heathkit@yahoogroups.com">heathkit@yahoogroups.com</a>>, <<a ymailto="mailto:heath@puck.nether.net" href="mailto:heath@puck.nether.net">heath@puck.nether.net</a>>,<br> <<a ymailto="mailto:heathkit@mailman.qth.net" href="mailto:heathkit@mailman.qth.net">heathkit@mailman.qth.net</a>><br>Subject: Re: [Heath] SB-401 / SB-303 LMO question<br>Message-ID: <001401d1ee22$9e0d8540$da288fc0$@rogers.com><br>Content-Type: text/plain; charset="iso-8859-1"<br><br>Thanks for all your answers everyone.<br><br>---Rob<br>------------------------<br>Hi<br><br>I have an SB-303 and SB-401 working together as a transceiver in ?locked?<br>mode with the (same) operating frequency for both the Rx and Tx controlled<br>by the Rx.? Can someone explain to me why the LMO frequency on the SB-303 is<br>suppose to change slightly when moving between USB and LSB, please?? I<br>thought I sort of understood this one time.<br><br>Thanks,<br>--- Rob VE3JQL<br><br><br><br>------------------------------<br><br>Subject: Digest Footer<br><br>_______________________________________________<br>Heath mailing list<br><a ymailto="mailto:Heath@puck.nether.net" href="mailto:Heath@puck.nether.net">Heath@puck.nether.net</a><br><a href="https://puck.nether.net/mailman/listinfo/heath" target="_blank">https://puck.nether.net/mailman/listinfo/heath</a><br><br><br>------------------------------<br><br>End of Heath Digest, Vol 68, Issue 3<br>************************************<br><br><br></div> </div> </div> </div></div></body></html>