<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt"><div><span>JPG:</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>There are a lot of rigs, especially the Japanese transceivers, that were designed to use the 6146B/8298A.</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span><br></span></div><div style="color:
rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>The neutralization in the Collins S-Line and KWM-2- series is a bit different from the usual circuit. The original neutralization circuit used a ceramic trimmer as the neutralization capacitor and, unfortunately, in well over 95% of the units, if the final amplifier tubes were replaced with the 6146B/8298A, or with a 6146W with a code date of after mid 1965, the ceramic trimmer literally "burned up".</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;
background-color: transparent; font-style: normal;"><span>The revised neutralization circuit that Collins "came up with", uses an air variable capacitor and there is a fixed capacitor and one resistor that are also changed.</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>Heath had a special run of General Electric 6146B/8298A tubes made to use in the HW-101 series transceivers. However, those tubes were basically 6146A/8298 tubes. Heath put a note in with those tubes which said that the only 6146B/8298A tubes that could be used in the HW-101 were those special
tubes.</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>It was unfortunate that RCA used the 6146B/8298A nomenclature for those tubes. RCA also initially said that the 6146B/8298A tubes were completely backwards compatible with the earlier versions. Because of this, the military changed the 6146W tubes from the 6146A/8298 to the 6146B/8298A WITHOUT changing the nomenclature! Unfortunately, the backwards compatibility did not work out in all situations.</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue',
Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>In the commercial two-way radios, which are type accepted, those radios designed for the 6146 and 6146A/8298 tubes would have to be modified to use the 6146B/8298A tubes. Making such modifications violate the type acceptance! However, especially Motorola, designed the later versions of the Motrac (the HHT "E" models, the LHT, and the MHT) to use the 8552/8032A/6883B tubes (the 12-volt equivalent of the 6146B series).</span></div><div></div><div> </div><div>Glen, K9STH</div><div><br><br></div><div>Website: http://k9sth.com</div><div class="yahoo_quoted" style="display: block;"> <br> <br> <div style="font-family:
HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 12pt;"> <div style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 12pt;"> <div dir="ltr"> <font size="2" face="Arial"> On Monday, October 14, 2013 6:09 AM, Bill Kuhn <BKuhn@kuhngroup.com> wrote:<br> </font> </div> <div class="y_msg_container">Kenwood hybrids use 6146bs.<br><br>Sent from my Windows Phone<br>________________________________<br><br>From: Chris Kepus <mailto:<a ymailto="mailto:ckepus@comcast.net" href="mailto:ckepus@comcast.net">ckepus@comcast.net</a>> <br>Sent: 10/13/2013 10:25 PM<br>To: 'Glen Zook' <mailto:<a ymailto="mailto:gzook@yahoo.com" href="mailto:gzook@yahoo.com">gzook@yahoo.com</a>> ; 'RAY FRIESS' <mailto:<a ymailto="mailto:rayfrijr@msn.com" href="mailto:rayfrijr@msn.com">rayfrijr@msn.com</a>> ; 'Gary H. Harmon, Jr.' <mailto:<a
ymailto="mailto:gharmon@idworld.net" href="mailto:gharmon@idworld.net">gharmon@idworld.net</a>> ; <a ymailto="mailto:heath@puck.nether.net" href="mailto:heath@puck.nether.net">heath@puck.nether.net</a>; 'Heathkit2' <mailto:<a ymailto="mailto:heathkit@mailman.qth.net" href="mailto:heathkit@mailman.qth.net">heathkit@mailman.qth.net</a>> ; 'Heathkit3 LIST' <mailto:<a ymailto="mailto:heathkit@yahoogroups.com" href="mailto:heathkit@yahoogroups.com">heathkit@yahoogroups.com</a>> <br>Subject: Re: [Heathkit] [Heath] 6146B Issues<br><br><br>Glen, <br><br><br><br>Your article on the 6146 family is very informative and helpful. However,<br>it begs the question..what to do with all those 6146B/8298A's? <br><br><br><br>Your article stated that Collins "figured it out" for the later S line<br>transmitters (amazing what necessity fosters).<br><br><br><br>I wonder if anyone has compared the Collins neutralization circuitry for the<br>early
transmitters to the latter ones? Could the later S-line approach<br>(whatever it is) work with other 2X 6146 rigs so that they would be "happy"<br>with the B's? <br><br><br><br>Are there any other known 2X 6146 rigs that can run B's without problems?<br><br><br><br>Glen.anyone?<br><br><br><br>73,<br><br>Chris<br><br>W7JPG<br><br><br><br><br><br><br><br>From: Heath [mailto:<a ymailto="mailto:heath-bounces@puck.nether.net" href="mailto:heath-bounces@puck.nether.net">heath-bounces@puck.nether.net</a>] On Behalf Of Glen Zook<br>Sent: Saturday, October 12, 2013 9:26 AM<br>To: RAY FRIESS; Gary H. Harmon, Jr.; <a ymailto="mailto:heath@puck.nether.net" href="mailto:heath@puck.nether.net">heath@puck.nether.net</a>; Heathkit2;<br>Heathkit3 LIST<br>Subject: Re: [Heath] [Heathkit] 6146B Issues<br><br><br><br>The DX-35, DX-40, and the DX-60 series "load down" the grid circuit. This,<br>in turn, requires considerably higher output from the driver
stage. As<br>such, Heath did not neutralize those transmitters. With the "loaded down"<br>grid, the 6146 in the final amplifier is much less likely to "take off" and<br>neutralization is not usually required. In most cases, the 6146B/8298A or<br>6146W tubes will work fine.<br><br><br><br>Of course, there are always exceptions. As such, I will not say that the<br>later tubes will work in every DX-35, DX-40, and DX-60 series. However,<br>there is a very good chance that the tubes will work fine.<br><br><br><br>Glen, K9STH<br><br><br><br>Website: <a href="http://k9sth.com/" target="_blank">http://k9sth.com</a><br><br><br><br>On Saturday, October 12, 2013 10:48 AM, RAY FRIESS <<a ymailto="mailto:rayfrijr@msn.com" href="mailto:rayfrijr@msn.com">rayfrijr@msn.com</a>> wrote:<br><br>Glen ... question.<br>Does this apply as well to the simple Heathkits like the DX 40 and DX 60?<br>I don't recall off hand that those
simple ones require or even have<br>provision for neutralizing.<br><br>Ray wa7itz<br><br> _____ <br><br><br><br><br><br>Date: Fri, 11 Oct 2013 18:46:40 -0700<br>From: <a ymailto="mailto:gzook@yahoo.com" href="mailto:gzook@yahoo.com">gzook@yahoo.com</a><br>To: <a ymailto="mailto:gharmon@idworld.net" href="mailto:gharmon@idworld.net">gharmon@idworld.net</a>; <a ymailto="mailto:heath@puck.nether.net" href="mailto:heath@puck.nether.net">heath@puck.nether.net</a>; <a ymailto="mailto:heathkit@mailman.qth.net" href="mailto:heathkit@mailman.qth.net">heathkit@mailman.qth.net</a>;<br><a ymailto="mailto:heathkit@yahoogroups.com" href="mailto:heathkit@yahoogroups.com">heathkit@yahoogroups.com</a><br>Subject: Re: [Heath] [Heathkit] 6146B Issues<br><br>There is no list. However, the 6146B/8298A and the 6146W tubes require<br>different neutralization and most of the Heath SB-Line equipment are very<br>"iffy" in whether or not they can
neutralize. Some units seem to work OK<br>but even more have problems. One can modify the neutralization circuit so<br>that the transmitters / transceivers will neutralize. However, for "plug<br>and play", one really needs to use the 6146, 6146A/8298, or 6293 tubes,<br>especially if they have problems neutralizing the tubes.<br><br><br><br>There are those who violently disagree with my article on the 6146 family of<br>tubes:<br><br><br><br><a href="http://k9sth.com/uploads/The_6146_Family_of_Tubes_1.pdf" target="_blank">http://k9sth.com/uploads/The_6146_Family_of_Tubes_1.pdf</a><br><br><br><br>However, over the years, I have literally seen well over 10,000 transmitters<br>that use the various 6146 family of tubes and my observations are outlined<br>in the article.<br><br><br><br>There are those who say that they have used the 6146B/8298A or 6146W in<br>transmitters that were designed for the 6146 or 6146A/8298 without
any<br>problems. I do believe them. However, I have received notice from a LOT<br>more people who say that they have had problems and went back to the earlier<br>tubes. It seems to be how the individual tolerances of the components "add<br>up" as to whether or not the later tubes work.<br><br><br><br>I have worked on individual transmitters, of exactly the same model, with<br>serial numbers within 10 of each other. With those transmitters 1 was happy<br>with the 6146B/8298A and the other 2 were very unhappy.<br><br><br><br>Glen, K9STH<br><br><br><br>Website: <a href="http://k9sth.com/" target="_blank">http://k9sth.com</a><br><br><br><br>On Friday, October 11, 2013 5:13 PM, "Gary H. Harmon, Jr."<br><<a ymailto="mailto:gharmon@idworld.net" href="mailto:gharmon@idworld.net">gharmon@idworld.net</a>> wrote:<br><br>I seem to remember there are some pieces of Heathkit that are not<br>HAPPY-HAPPY-HAPPY with 6146B tubes. Is
this a myth or is there a list of<br>pieces that prefer to not see a 6146B?<br><br><br><br>Thanks and 73, <br><br><br><br>Gary H. Harmon, Jr. - K5JWK<br><br>6003 Archwood<br><br>San Antonio, TX 78239-1504<br><br>210.657.1549h / 210.884.6926c/t<br><br><br><br>"Retirement means every day is a Saturday except Sunday"<br><br><a href="http://www.grissomroadcoc.org/" target="_blank">http://www.grissomroadcoc.org </a><<a href="http://www.grissomroadcoc.org/" target="_blank">http://www.grissomroadcoc.org/</a>> <br><br><br><br><br><br>______________________________________________________________<br>Heathkit mailing list<br>Home: <a href="http://mailman.qth.net/mailman/listinfo/heathkit" target="_blank">http://mailman.qth.net/mailman/listinfo/heathkit</a><br>Help: <a href="http://mailman.qth.net/mmfaq.htm" target="_blank">http://mailman.qth.net/mmfaq.htm</a><br>Post: mailto:<a ymailto="mailto:Heathkit@mailman.qth.net"
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