OK, after reading a good number of post on aligning the K2 transmitter, and
adding my own observations, I think I finally have my head around the process. I don't know that this has been summarized in a single post, and the intent of this post is to verify what I think I now know, plus provide some information for future builders. Firstly, I am not a heavyweight (or even a lightweight for that matter) in RF electronics or circuitry, but I obviously know enough to be able to assemble a kit such as the K2. Having said (typed?) that, if I am off base with my assumptions and observations about the alignment process, would those in the know please point out the errors in my logic. There are two key points about the alignment process. First, from what I have read here on the reflector, it appears that the ALC circuit is bypassed whenever the K2 is placed into 'tune' mode. Because of this, there is a good chance you will see different power level readings on the internal watt meter each time the K2 is place into 'tune'. These different power levels are also reflected on an external watt meter (I'm using an OHR WM-2 ). In my own case I was seeing three different ranges of power output (roughly 1.4-1.7, 2.2-2.7, 3.8-4.1). Second, and this is the important one, these power level fluctuations really don't matter because the process is really not about setting the output power level. The goal is to peak the inductors. And this can be done no matter what power level is showing on the watt meter. Having the OM-2 did help make sense of the process. No matter what the power level was, the peak spot for the inductor was consistent across the various levels. In other words, you adjust the inductor/caps to achieve the peak level of power for whatever range of power is showing on the watt meter. In normal use, I'm achieving an output level consistent with what I have dialed power control to. It seems my reception has also improved. Hopefully this will help make some sense of the transmitter alignment process. And again, if I am off base in any way, please point this out. 73 Don Herring W4DHH ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Don,
Your analysis is "right on". The only thing I can add is that *if* during the tuning process, the output power rises significantly (let's say to greater than 5 watts), there is a possibility that you will not be able to discern the peak because the RF Gain of the transmit stages may hit a limit and mask the peak. That is why the instructions tell you to reduce the power if it soars too high. You can reset the power level by either moving the Power control or exit TUNE and re-enter it. I use the later method, just a tap followed by a press of the TUNE button - my fingers are well practiced at it!. 73, Don W3FPR On 9/9/2010 9:16 AM, Don Herring wrote: > OK, after reading a good number of post on aligning the K2 transmitter, and > adding my own observations, I think I finally have my head around the > process. > > I don't know that this has been summarized in a single post, and the intent > of this post is to verify what I think I now know, plus provide some > information for future builders. > > Firstly, I am not a heavyweight (or even a lightweight for that matter) in > RF electronics or circuitry, but I obviously know enough to be able to > assemble a kit such as the K2. > > Having said (typed?) that, if I am off base with my assumptions and > observations about the alignment process, would those in the know please > point out the errors in my logic. > > There are two key points about the alignment process. > > First, from what I have read here on the reflector, it appears that the ALC > circuit is bypassed whenever the K2 is placed into 'tune' mode. Because of > this, there is a good chance you will see different power level readings on > the internal watt meter each time the K2 is place into 'tune'. These > different power levels are also reflected on an external watt meter (I'm > using an OHR WM-2 ). In my own case I was seeing three different ranges of > power output (roughly 1.4-1.7, 2.2-2.7, 3.8-4.1). > > Second, and this is the important one, these power level fluctuations really > don't matter because the process is really not about setting the output > power level. The goal is to peak the inductors. And this can be done no > matter what power level is showing on the watt meter. > > Having the OM-2 did help make sense of the process. No matter what the > power level was, the peak spot for the inductor was consistent across the > various levels. > > In other words, you adjust the inductor/caps to achieve the peak level of > power for whatever range of power is showing on the watt meter. > > In normal use, I'm achieving an output level consistent with what I have > dialed power control to. It seems my reception has also improved. > > Hopefully this will help make some sense of the transmitter alignment > process. > > And again, if I am off base in any way, please point this out. > > 73 > > Don Herring > W4DHH > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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