++++++++++++++++++++++++++ See also K2 Option Notes ++++++++++++++++++++++++++ Date: Wed, 15 Aug 2001 17:29:42 -0400 From: "Mark J. Dulcey" Subject: [Elecraft] K2 Un-Modules I wrote an article about some little things I built recently... I'm thinking this could become a Tech Note at Elecraft, but I'd like comments first. Here's the link: http://mail.buttery.org/mark/unmodule/ Let me know what you think... The beginning of the article (to give you an idea what it's about): The K2 modules (KSB2, KNB2, K160RX, KAT2) add useful capabilities to the K2. However, there are times when you might want to remove one or more modules from your K2. Installing many of the modules requires that you remove jumpers and/or components from the RF board of the K2, so you can't remove the modules by simply unplugging them. The usual procedure for removing a module is to unplug the module, and then put back the removed components and jumpers. If you are permanentely removing the module, that's fine, but you might want to take it out temporarily, for any of the following reasons: * Troubleshooting a problem * Comparative performance testing (how does a module affect sensitivity, dynamic range, or ultimate filter rejection?) * Minimizing weight and/or power consumption for field use Enter the Un-Modules! By building these simple circuits on header connectors, you can remove one or more modules from your K2 without any need to modify your RF board. The Un-Modules are simple and inexpensive to build, too! +++++++++++++++++++++++ Date: Thu, 16 Aug 2001 08:17:19 -0400 From: "Mark J. Dulcey" Subject: Re: [Elecraft] K2 Un-Modules Jay Rutherford wrote: > Mark, > > Nice work on the un-modules. I think they should have a place on > the Elecraft page for tips and hints. I do seem to recall a couple of > other parts, though, that come and go with the SSB module? I have > so many of the little mods on board that I forget which are which. I referred to the schematic and the building instructions when I designed the un-modules; all the parts are accounted for. When you install the KSB2, you remove one coupling capacitor, plus two jumpers. The three parts of that un-module account for all of those. The interesting one is the Un-KNB2. When you install the KNB2, you remove three resistors from the board (the -5dB pad), replacing one of them with a jumper. You also remove a bypass jumper from the board. The Un-KNB2 puts the -5dB pad on the un-module, so you can just plug it in and leave the jumper that you installed in place of R89 in place on the RF board. Looking at the schematic, the pad ends up where W5 is, rather than where it is shown; in effect, R89 has taken the place of W5, and W5 has been replaced by the circuit formed by R88, R89, and R90. Obviously, the effect is exactly the same. The purpose of that 5dB pad, by the way, is to make sure that the gain distribution of the K2 is similar, whether or not you have the KNB2 installed. The KNB2 has a bandpass filter (used primarily for its group delay rather than its filter characteristics) with a 6dB insertion loss; the pad introduces a similar loss at the same point in the circuit. +++++++++++++++++++++++++++ Date: Fri, 31 Aug 2001 07:41:44 -0400 From: Larry Johnson Subject: [Elecraft] Questions on T2 for K2 --- snip --- 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 +++++++++++++++++ Date: Thu, 27 Sep 2001 07:02:51 -0400 From: "Mark J. Dulcey" Subject: Re: [Elecraft] KSB2 & KAF2 Edmund T. Wright wrote: > Thanks to all who gave advice. > > I have ordered the KSB2 & KAF2 modules. As suggested I have read through > the K2 manual and found that instructions for the KSB2 module modifications > are there. The KAF2, being new, is not described, but I am certain that > when I receive those modules that I will be able to figure out what to do to > facilitate installing that modules. The KAF2 is trickier. You can't just install the connectors like you do for the other options, because the bypass jumpers go in the same board locations as the connectors. You could put in the connectors, and then build something similar to my unmodules (http://mail.buttery.org/mark/unmodule/); you would need two connectors (3 and 5 pin) with jumpers connecting pins 1 and 2 of the two connectors together. (I'm planning to add KAF2 info to the article soon...) ++++++++++++++++++++ From: "Mike Rioux" To: "'Francis Belliveau'" , Subject: RE: [Elecraft] How do I config the K2 to put out RF on the original BNC connector? Date: Sat, 10 May 2003 10:42:17 -0400 Try Ke1l's site for the 'unmodules': http://mail.buttery.org/mark/unmodule/ Mike, W1USN +++++++++++++++++++