Hi Don, and All, All done. Ken, K3IU, sent me his plots of various fixes and it convinced me to change out the resistors. The results seem to me to be dramatic. Here are the results before and after changing the resistors.
|--c80+c81=5600 pf only-------| +new r19+r20 ________________________ ____________ SSB 80M 3773 100W "80" 100W "80" 40M 7251 100W "99" 100W "75" 30M 10114 90W "110" 105W "85" 20M 14290 70W "110" 100W "100" 17M 18136 100W "90" 100W "70" 15M 21350 110W "100" 105W "80" 12M 24950 100W "110" 105W "70" 10M 28400 100W "110" 105W "70" CW 80M 3600 105W "60" 100W "60" 40M 7050 110W "70" 100W "60" 30M 10115 98W "110" 100W "60" 20M 14050 100W "70" 100W "60" 17M 18080 100W "70" 100W "60" 15M 21100 100W "60" 100W "60" 12M 24900 100W "60" 100W "60" 10M 28050 110W "70" 100W "60" The fix definitely smoothed out the power on cw and ssb. Still a dip at 20 and 30 meters, but Ken's plots show this and I get 100 W plus on all bands. I got some hot rig here, a keeper. I just got VC9W IOTA NA-014 on 14015, first try with 100 Watts. With all the techniques we have learned using 5 Watts or less, 100 Watts is like shooting fish in a barrel. I can see how the amp is nice for cracking really big pileups, and for traffic net work. Someone, asked a while ago what K2 builders would have done different if they could do it over again. For me, I wouldn't change a thing! The mistakes I made were all inexpensively repairable, and I learned something about the radio, and it gave me the confidence to know that whatever happens, I can fix it. I will redo the wattmeter calibrations soon for the KAT100/KPA100. All three of my external wattmeters were pretty close, so close enough for government work. I may even parallel a resistor in my MFJ-949E dummy load to bring down the resistance a little bit. I need to calibate my wattmeters too with an rf probe. Thanks to all, Steve, W2MY K2 #402 -----Original Message----- From: W3FPR - Don Wilhelm [mailto:[EMAIL PROTECTED] Sent: Sunday, July 31, 2005 5:29 PM To: Steven Pituch; [email protected] Subject: RE: [Elecraft] Power Out of KPA100 Steve, Put in the new resistors Scott sent to you (yes, the 5600 pf capacitors can stay) and then calibrate the wattmeters in the KPA100 and the KAT100 and you should be all set. If you can buy, beg, borrow or otherwise acquire a good 50 ohm non-reactive dummy load you will find the wattmeter calibration much more accurate. I recommend using an RF Probe to measure the RF Voltage at the dummy load rather than relying on any wattmeter - even the best are spec'ed for only 5% of full scale when properly calibrated, so on a 100 watt scale, even the best can be off by as much as 5 watts - the run of the mill wattmeters can only be trusted to 20% of full scale (20 watts possible error on a 100 watt scale) until proven otherwise. 73, Don W3FPR -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.9.7/60 - Release Date: 7/28/2005 _______________________________________________ Elecraft mailing list Post to: [email protected] 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
