It's very unlikely you'd find any benefit from using this mod running 5 watts PEP on any band. That mod was specifically to provide full K2 output for those units who, because of the combination of the particular K2 and mic used, don't make a full 10 watts PEP output on all bands. The mod would help at 100 watts in the same sense that it helps at 10 watts: it provides the overall gain to make sure one can get a full 100 watts PEP on all bands.
In SSB mode, the power output from the K2 is a function of the overall gain of the transmitter RF system and, within limits, the amount of audio supplied to the balanced modulator. The overall gain of the transmitter RF system falls off at the higher frequencies and is usually the least on 10 meters. So most operators who notice low output notice it on 10 meters. Of course, there's a limit to amount of audio the balanced modulator can handle, so simply adding audio gain isn't always the best choice. Indeed, excess audio gain can backfire with distortion, although the speech amplifier I.C. used in the K2 has an internal automatic gain control that should limit the distortion in most situations. John took a different approach with his 2N2222 mod. He increased the transmit RF path gain mostly by providing a better impedance match at the output of the balanced modulator. His notes say that it provides about 10 dB of gain. I'm using an electret mic that, with my particular K2, provides full SSB output from 160 through 10 meters, although there is very little "headroom" at 10 meters. I get just 10 watts output in SSB mode on 10 meters without the KPA100 switched in and 100 watts PEP with the KPA100. Although I've not added John's mod, it has been on my "to do" list in case I'd like to play with a microphone with less output. I can say from first-hand experience helping John test some of his mods and through incorporating them on my K2 that John's mods are well thought out, well engineered and have always worked very well. Several of his mods have become in integral part of the K2 as currently shipped. Ron AC7AC -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Roy Morris Sent: Saturday, June 03, 2006 9:42 AM To: elecraft@mailman.qth.net Subject: [Elecraft] KSB2 in K2/100 I would like to hear from anyone who has K2/100s with both the unmodified KSB2 and the modified KSB2 with the KI6WX 2N2222 amp mod (and 1.08 firmware). How does this mod affect mic gain and VOX operation? How does the absence of this mod affect mic gain and VOX operation? Does the mod help SSB modulation on 10 meters with the power level set at 5 watts? Do you find this mod helpful at 100 watts? Thanks for your input. Roy Morris W4WFB _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
