> BTW, I hope the KPA800/1600 will either provide negative > going ALC as an option or have a built-in fast acting > attenuator to obviate the need for external power control if > they want a broader audience than K3 owners ;-)
I would hope they have an attenuator that can be adjusted in 0.5 dB steps on a per band basis to match available drive to the level required for rated output. The problem with many rigs and rig/amplifier combinations is that the rig has excess gain in the early stages to allow "headroom" on the band with lowest overall gain and ALC (external or internal) is used as the primary means of controlling (limiting) output power. Unfortunately, ALC can only come into play once the desired level is reached and the excess gain gives rise to significant overshoot/click/wave sharpening issues. One can see significant variation in gain vs. band looking at the QEX article on the Tokyo High Power HL-2.5kl. The amp includes a fixed 3 dB pad on the input but the output power (gain) varies from a low of 1400 W (11.4 dB) on 1.8 MHz to a high of 2050 W (13.1 dB) on 10 MHz. In fact, overall system performance would be improved by using a fixed 2 dB attenuator followed by selectable 0.5 and 1.0 dB pads. Negative going ALC is fine to touch up the level (within the .5 dB bands) and to provide a "failsafe" tool to reduce drive if the SWR or collector/drain current goes too high but it has no place as the primary power (gain) setting tool. 73, ... Joe, W4TV > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Larry Phipps > Sent: Monday, December 03, 2007 10:30 AM > To: elecraft@mailman.qth.net > Subject: [Elecraft] Neat K3 Video! > > > Right on, Bill. Joe's comments are some of the most useful I > have seen in all the K3 related postings. With all the menu > choices the K3 has, it seems like they could have > incorporated (could still incorporate?) the option of > "industry standard" or "Elecraft" choices for some of these > functions. I think we have already heard from Eric on the > subject of ALC. I don't use it for the reasons he gave, but > some people do, and I believe he has said that it will be > addressed. > > BTW, I hope the KPA800/1600 will either provide negative > going ALC as an option or have a built-in fast acting > attenuator to obviate the need for external power control if > they want a broader audience than K3 owners ;-) > > 73, > Larry N8LP > > > > KK7P re W4TV: > >Please be assured that we appreciate your thoughtful and > constructive > comments on the K3. > > I strongly second that Lyle...I only wish Joe had > been one of your beta testers because of the quality of > his suggestions. Keep that in mind for the K4! ;-) > > 73, Bill W4ZV > > _______________________________________________ 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
