KSB2 in K2/100
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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
No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.394 / Virus Database: 268.8.1/355 - Release Date: 6/2/2006 _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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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: [hidden email] [mailto:[hidden email]] On Behalf Of Roy Morris Sent: Saturday, June 03, 2006 9:42 AM To: [hidden email] 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: [hidden email] 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 |
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In reply to this post by Roy Morris-6
Roy;
I'm confused. Previous posts indicate you have already made this mod (and the secondary ALC mod) to your KSB2. If so, what have you found? I am contemplating the mod (and possibly the secondary ALC mod) for my K2/100. Thus I am very interested in comments on both mods... On Jun 3, 2006, at 9:41 AM, Roy Morris wrote: > 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 No virus > found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.1.394 / Virus Database: 268.8.1/355 - Release Date: > 6/2/2006 > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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 - Jack Brindle, W6FB ------------------------------------------------------------------------ --------------------- _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Roy Morris-6
Roy,
As this mod is after the balanced modulator it does nothing to affect the mic gain or improve the VOX operation. 73 Stewart G3RXQ On Sat, 3 Jun 2006 12:41:42 -0400, Roy Morris wrote: > 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: [hidden email] 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 |
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In reply to this post by Roy Morris-6
I know this message is a bit old, but I've been too tied up with other
projects to read the reflector mail for the last two months (fyi - the reflector generated over 2000 emails in the last 2 months). The increased gain mod I did for the KSB2 was originally designed to increase the transmit gain in SSB for a barefoot K2. The original K2 had difficulty reaching 10 watts of power output in SSB on 10 meters. When you drove the audio input harder to get to full power, the K2 would start to clip on the audio peaks. This does not create a wider bandwidth signal because the SSB modulator is followed by the SSB filter, but it does increase the audio distortion. I added the extra emitter follower stage to increase the overall IF gain in the SSB transmit signal path. This mod should not be necessary with the KPA100, since it can reach full power with only a few watts of drive. Some folks have reported that the emitter follower stage can cause power output instability when the KPA100 is installed. There is at least one fix around that reduces the gain of the emitter follower stage by increasing the emitter resistor value and apparently eliminates this instability. I would recommend that the emitter follower gain stage not be used in a K2/100 since it does appear to cause a stability problem, and there is no need for the extra gain on 10 meters. -John KI6WX ----- Original Message ----- From: "Roy Morris" <[hidden email]> Sent: Saturday, June 03, 2006 9:41 AM 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: [hidden email] 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 |
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John - KI6WX said:
(fyi - the reflector generated over 2000 emails in the last 2 months). ================================== No wonder I havn't got the house painted! Rick Dettinger K7MW _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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