<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue-Light, Helvetica Neue Light, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:8pt"><div id="yiv4860863340"><div><div style="color: rgb(0, 0, 0); font-family: HelveticaNeue-Light, 'Helvetica Neue Light', 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 8pt; background-color: rgb(255, 255, 255);"><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_6_1408462353855_4" style=""><span class="yiv4860863340" id="yiv4860863340yui_3_16_0_6_1408462353855_52" style="">Here is the reply to this that I sent yesterday:</span></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_6_1408462353855_4" style="color: rgb(0, 0, 0); font-size: 11px; font-family: HelveticaNeue-Light, 'Helvetica Neue Light', 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span
class="yiv4860863340" id="yiv4860863340yui_3_16_0_6_1408462353855_55" style=""><br clear="none" class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_11903" style=""></span></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9590" style=""><span class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9589" style="">Some people do use RG58/U cables for the interconnection. However, that
often requires retuning of the equipment as well as, sometimes, not enough injection, especially from the heterodyne oscillator into the transmitter.</span></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9607" style="background-color:transparent;"><br clear="none" class="yiv4860863340" style=""></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9610" style="background-color:transparent;"><span class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9609" style="">It is the capacity of the interconnect cables that affect the tuning of the circuits.</span></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9612" style="background-color:transparent;"><br clear="none" class="yiv4860863340" style=""></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9615" style="background-color:transparent;"><span class="yiv4860863340"
id="yiv4860863340yui_3_16_0_1_1408462353855_9614" style="">If additional circuitry was used in the receivers (SB-300, SB-301, and SB-303), then the price of the kit would have to be increased.
Heath furnished the RG62/U cable in the receiver kit. Therefore, amateur radio operators did not have to obtain cable. Remember, Heath had no idea that the SB-30X receivers were going to be used over 40-years later and, as such, they didn't even consider using RG58/U cables.</span></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9617" style="background-color:transparent;"><br clear="none" class="yiv4860863340" style=""></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9620" style="background-color:transparent;"><span class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9619" style="">Using RG59/U cable for the interconnect cables does result in less capacitance for the assemblies and, sometimes, that works OK on the 10-meter band. But, for best operation, use the 24-inch RG62/U cables.</span></div><div class="yiv4860863340"
id="yiv4860863340yui_3_16_0_1_1408462353855_9620" style="background-color:transparent;"><span class="yiv4860863340" id="yiv4860863340yui_3_16_0_6_1408462353855_65" style=""><br clear="none" id="yiv4860863340yui_3_16_0_1_1408462353855_14028"></span></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9620" style="background-color:transparent;"><span class="yiv4860863340" id="yiv4860863340yui_3_16_0_6_1408462353855_68" style=""><br clear="none"></span></div><div class="yiv4860863340" style=""></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9623" style=""><br clear="none" id="yiv4860863340yui_3_16_0_1_1408462353855_12958"></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_1_1408462353855_9623" style="">You might add an amplifier to each of the 3-outlets in the SB-303 to match the output of the signal without having problems with using cable other than the RG62/U. Doing so would require
some work and expense. However, at least to me, since I am a firm believer in the principles of the conservation of my finances (you can say "cheap and lazy" if you wish) doing so is a lot of work when RG62/U is still readily available.</div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_6_1408462353855_6" style=""></div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_6_1408462353855_8" style=""> </div><div class="yiv4860863340" id="yiv4860863340yui_3_16_0_6_1408462353855_10" style="">Glen, K9STH
<br clear="none" class="yiv4860863340" style="">
<br clear="none" class="yiv4860863340" style="">Website: http://k9sth.net</div> <div class="qtdSeparateBR"><br><br></div><div class="yiv4860863340yqt4105285751" id="yiv4860863340yqt36634"><div class="yiv4860863340yahoo_quoted" id="yiv4860863340yui_3_16_0_6_1408462353855_13" style="display: block;"> <div class="yiv4860863340" style="font-family: HelveticaNeue-Light, 'Helvetica Neue Light', 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 8pt;"> <div class="yiv4860863340" style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 12pt;"> <div class="yiv4860863340" dir="ltr" style=""> <font class="yiv4860863340" size="2" face="Arial" style=""> On Tuesday, August 19, 2014 10:20 AM, Robert Myers <rsmyers@rogers.com> wrote:<br clear="none" class="yiv4860863340" style=""> </font> </div> <br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340"
style=""> <div class="yiv4860863340" style="">Question about the SB-303 / SB-401 interconnection cables *required* for the<br clear="none" class="yiv4860863340" style="">HFO, BFO and LMO.<br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style="">As I am sure most are aware, the SB-303 and SB-401 manuals call for the<br clear="none" class="yiv4860863340" style="">following cables
to be connected between the various SB-303 oscillator<br clear="none" class="yiv4860863340" style="">output sockets and the corresponding SB-401 oscillator input sockets:<br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style="">SB-303 ‘BFO OUT’ -> 24” RG-62/U -> SB-401 ‘RCVR BFO’<br clear="none" class="yiv4860863340" style="">SB-303 ‘HFO OUT’ -> 24” RG-62/U -> SB-401 ‘HET OSC’<br clear="none" class="yiv4860863340" style="">SB-303 ‘LMO OUT’ -> 24” RG-174/U -> SB-401 ‘RCVR LMO’<br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style="">It seems to me that the designers, for some reason, decided to incorporate<br clear="none" class="yiv4860863340" style="">the various cable capacitances (that result from their specified lengths)<br clear="none" class="yiv4860863340" style="">and their characteristic impedances, along with
the input impedances of<br clear="none" class="yiv4860863340" style="">those various oscillator inputs of the SB-401, into what amounts to<br clear="none" class="yiv4860863340" style="">‘essential operating circuitry’ of the corresponding oscillators based on<br clear="none" class="yiv4860863340" style="">the
SB-303. (But why? To save money?)<br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style="">Is the requirement for 'cable weirdness' due to the various oscillators’<br clear="none" class="yiv4860863340" style="">output circuitry within the ‘303, or is it due to the requirements of<br clear="none" class="yiv4860863340" style="">various oscillators’ input circuitry within the ‘401? Or is it a<br clear="none" class="yiv4860863340" style="">combination of both?<br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style="">I mean, if the ‘303 requires a particular capacitance ‘hanging off’ the<br clear="none" class="yiv4860863340" style="">LMO’s output socket (such being provided by exactly 24 inches of RG-174/U)<br clear="none" class="yiv4860863340" style="">in order to function properly, as well as a 50 Ohm load (inside the 401<br clear="none"
class="yiv4860863340" style="">during transceiver), would it not have been better to do something like<br clear="none" class="yiv4860863340" style="">provide all those necessities *within* the ‘303 (right at the LMO<br clear="none" class="yiv4860863340" style="">oscillator) and follow that by an isolating
buffer/voltage-follower (still<br clear="none" class="yiv4860863340" style="">inside the ‘303) with a 50 Ohm output impedance? You could do the same for<br clear="none" class="yiv4860863340" style="">the HET, and BFO oscillators’ circuitry as well – thus allowing for<br clear="none" class="yiv4860863340" style="">arbitrary lengths of, say, RG-58/U cables (not different cables) for<br clear="none" class="yiv4860863340" style="">interconnection of the HET, LMO, and BFO sockets between the two units.<br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style="">Is there a fix for this cable 'weirdness,' allowing the cables to be the<br clear="none" class="yiv4860863340" style="">same type (say, 50 Ohm RG-58 since you need that for the antenna<br clear="none" class="yiv4860863340" style="">connections, for sure), and their lengths to be not critical?<br clear="none" class="yiv4860863340" style=""><br clear="none"
class="yiv4860863340" style="">Thanks,<br clear="none" class="yiv4860863340" style="">Rob Myers, VE3JQL<br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style="">_______________________________________________<br clear="none" class="yiv4860863340" style="">Heath mailing list<br clear="none" class="yiv4860863340" style=""><a rel="nofollow" shape="rect" class="yiv4860863340" ymailto="mailto:Heath@puck.nether.net" target="_blank" href="mailto:Heath@puck.nether.net" style="">Heath@puck.nether.net</a><br clear="none" class="yiv4860863340" style=""><a rel="nofollow" shape="rect"
class="yiv4860863340" target="_blank" href="https://puck.nether.net/mailman/listinfo/heath" style="">https://puck.nether.net/mailman/listinfo/heath</a><br clear="none" class="yiv4860863340" style=""><br clear="none" class="yiv4860863340" style=""></div> </div> </div> </div></div> </div></div></div></div></body></html>