+++++++++++++++++++++++++++++++ Date: Tue, 15 May 2001 11:53:35 -0700 From: Louis Hlousek Subject: Re: [Elecraft] Minor problems with K2 #1944 Hi Rich, 1.)I would suggest rechecking all the CAL FIL settings for both upper and lower sidebands per the instruction on pages 85 and 86 in the manual . There's lots of numbers to get right and I know I messed up a few times myself before getting them all correct. As I'm sure you know LSB is generally used on 40 and lower and USB on the Higher bands. Also the K2 switches sidebands above 17 meters. Upper and lower ssb operation is determined by the CAL FIL settings. The difference is in the BFO frequency for each of the 4 filters for both USB and LSB operation (8 total filters). Since USB, LSB and IF sideband are swapping around between bands it is possible for it to work right on some bands and not on others. 2.) Your current reading are right in line with mine and another K2 that I have worked with. I set my CAL CUR limit to 3 amps. 3.) Extending the secondary further around T2 seems to help a great deal. It should occupy at least 180 degrees around the coil. More is better. Elecraft's Gary recommends routing the secondary wires between the T2 and the PCB and elevating T2 about 1/16" above the board. I first had my secondary covering 180 degrees but rewinding it to cover about 230 degrees and following Gary's advice got me another 1.5 watts or so. Luigi W7DZN +++++++++++++++++++++++++++++++ Date: Fri, 31 Aug 2001 06:39:55 -0700 From: pqd Subject: Re: [Elecraft] Questions on T2 for K2 a> wind it like the diagram shows. b> the red dot is OK. a 'new' identification technique but it's good to use. david nr1ss 0x8a8 - ----- Original Message ----- From: "Larry Johnson" To: Sent: Friday, August 31, 2001 04:41 Subject: [Elecraft] Questions on T2 for K2 > I'm into the home stretch building K2 S/N 2177, and I have two questions > regarding transformer T2. > > First, Figure 6-26 shows wire ends 1 and 4 coming up through the center > of the core, and ends 2 and 3 coming down through the core. This is > different from the other (non-bifilar) transformers (e.g. Figure 6-25). > To achieve this, the green wire would have to be wound with a handedness > different from all the other toroids, which also means it would cross > the red wire once per turn. (The picture of T2 in the application note > "Winding T2 for maximum output on 12/10M" doesn't show such > crossovers.) Should I just assume that Figure 6-26 is in error, and > wind T2 like the others, or am I missing something? > > Second, one of the FT37-43 ferrite cores that came with the kit has a > red paint dot on it. Does this have any significance? > > BTW, KE1L's "un-modules" have another use, which he didn't mention in > his article: they're great if you building a kit with options, and you > don't want to install components temporarilty to test the base unit. I > was planning to do something along the same lines by sticking jumpers > and component leads directly into the sockets, but his solution of using > headers is obviously better (and made me feel stupid for not thinking of > it myself). I saw the app note just as I was getting to the point of > testing the receiver and I didn't want to wait for a mail-order, but I > found I could unsolder a header from an old computer board, cut it > apart, and use the pieces. Great stuff! > > --73, Larry, K1LJ ++++++++++++++++++++++ ate: Mon, 21 Jan 2002 11:42:30 -0800 From: lhlousek Subject: Re: [Elecraft] Winding of T2 - K2 To: elecraft list , Jeff Anderson << Does it (the winding direction of the secondary T2) matter?>> No. It can be wound either way. The are no dots on the symbol for T2 on the schematic. Dots (as on the symbols for T5 and T6 on the RF board) would signify that relative sense of the windings is important. Also, analysis of the schematic indicates that it isn't. I have both the windings on T2 going the same direction. Lou ----- Original Message ----- From: "Jeff Anderson" To: "ELECRAFT List" Sent: Monday, January 21, 2002 9:28 AM Subject: [Elecraft] Winding of T2 - K2 > Hi All, > > Just when I thought I was getting the hang of this toroid stuff... > The diagram in the manual shows that the secondary winding of this > transformer is wound in the opposite direction of the primary winding. It > seems that this would require each turn of the secondary winding to cross > over a primary winding turn, rather than fit nicely between each primary > turn. Is this correct? Does it matter? > I've looked at Gary's instructions on the web site for winding this > transformer, and the photo shows the secondary windings fitting evenly > between the primary windings, but I can't tell from the photo which > direction the secondary was wound. > How did the rest of you wind T2? How do the windings lay on each other? > Any help is appreciated. > > Thanks, > -- Jeff Anderson KD7PAW > K2 #2320 ++++++++++++++++++ Date: Mon, 26 Aug 2002 08:52:12 -0500 To: , "Elecraft at Mailman. Qth. Net" From: "Timothy A. Raymer" Subject: Re: [Elecraft] Raised T2 falling down Sverre, In addition to Kevin's perf board, another trick that was suggested by one of the forum folks was using double sided foam tape. I got some from Wal-Mart, and used it for mine. It gave just the right amount of height to it. It also came in handy for the K-160 board. That is the only board so far that has the torroids laying horizontally, with the wire connections on only one end. A couple of pieces of double-sided sticky tape keeps them in place, and looking sharp. Tim Raymer At 16:17 08/25/2002 +0200, Sverre Holm - LA3ZA wrote: >I have seen several messages about raising T2 1/16 to 1/8 of an inch >above the board (1-4 mm). Supposedly it helps raise the maximum output >power - I have never measured to check this. >Just wanted to share my experience in case someone else expects their T2 >still to be raised after a long time. Timothy A. Raymer Missouri Department of Health and Senior Services ++++++++++++++++++ From: "Don Brown" To: "Elecraft" Subject: Re: [Elecraft] Winding Transformer T2 in K2 Date: Thu, 14 Nov 2002 22:13:54 -0600 Hi Wind it so the windings go in the same direction and the red and green wires do not cross over Don Brown KD5NDB ----- Original Message ----- From: "Parker Buckley" To: Sent: Thursday, November 14, 2002 5:42 PM Subject: [Elecraft] Winding Transformer T2 in K2 Looking at Fig 6-26 in the assembly manual, and based on the how the ends of winding 3-4 depart the core, it looks like these turns run opposite in direction to 1-2, which would result in the windings crossing at each turn. The figure doesn't show the crossings. Somehow, I bet this is important. Thanks in advance for the help. Parker WD8JOL ++++++++++++++++ Date: Thu, 14 Nov 2002 23:40:27 -0600 To: "Parker Buckley" , From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: [Elecraft] Winding Transformer T2 in K2 Hi Parker: >Looking at Fig 6-26 in the assembly manual, and based on the how the ends >of winding 3-4 depart the core, it looks like these turns run opposite in >direction to 1-2, which would result in the windings crossing at each >turn. The figure doesn't show the crossings. Somehow, I bet this is >important. Thanks in advance for the help. Actually, you can wind the secondary in EITHER direction (WITH or CROSSING the turns). But if you wind it scroosing the turns (as instructed) I believe the wires will come off the core more appripriately placed than if they were laid on to lay WITH the other turns. Your choice. No diff in operation. 73, Tom Hammond N0SS +++++++++++++++++