W5JAW has a click free MP but he says making it totally click free required much more work than just the common modifications - the fix included a multi-stage ALC modification.
Two comments from Jim: "As I told you some time back, I worked real hard on optimizing the keying waveform on my rig. It's as close to optimum as I could get it; the result is "Gaussian" in shape. Very narrow bandwidth, yet still clear copy up to 100 WPM. Due to the messy way that Yaesu implemented the keying, it was necessary to modify several stages of the IF string to achieve this without screwing up the QSK operations." and: "Re: Key click mods: The W8JI mod does help a lot, but is far from optimum. Much better than nothing. Because it depends on a simple RC filter on the gate of a MOSFET, it provides a very asymetrical wave shape. Also, since the transfer characteristics of the FET vary widely, the rise/fall times do too. Also, I still enjoy QRQ operations, with QSK, and these simple fixes don't work very well for that. The other problem with these rigs is that even with good wave shaping, there can still be a significant thump on the first dit of a string if there has been a 1 second delay or more since the last character was sent. This is due to the way the ALC works. The power level is controlled by setting a threshold in this circuit. The attack time is very fast, and will create a click, even with earlier waveshaping. I solved this by decoding the CW mode from available logic levels, and then, when in this mode, biased the ALC input just below threshold level. This makes the first dit after a delay look same as any following. I can always tell when someone is using a 1000mp with a simple click fix. No clicks except at the start of a new word." Dunc, W5DC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
