Brian, Don't worry about the fan - so set it to "nor". Observe the current into the KPA100 and add 400 ma. That is your target for the initial collector current. Take the KAT100 out of the picture for this adjustment - unplug the AUX DC cable from the KAT100. When you go to CW TEST mode and TUNE (with power set to greater than 11 watts), the current rise should be set as close to 400 ma as possible - if the receive current is 230 ma, you would adjust the bias so that the initial TX current is 630 ma. The current will increase rapidly during the TUNE interval, so watch you DMM initially - the first displayed reading may be invalid due to timing, but the second is the reading you want. Exit and re-enter TUNE as many times as required to get it right.
73, Don W3FPR On 5/11/2011 11:35 PM, Brian - N5BCN wrote: > Hi Don, > > Perhaps against my better judgement, I adjusted the bias current of the > KPA100 in the KAT100-2 remoted from the K2. Now I'm thoroughly confused! > :-( > > The current measurements of the KPA100 in the K2 make sense to me: > Power< 11 W, Current ~ 380 mA > Power> 11 W, Current ~ 520 mA > Power> 11 + Fan on Lo, Current ~ 565 mA > Add 400 mA for the bias current, and you get a target of ~965 mA. > > > The current measurements of the KPA100 in the KAT100-2 remoted from the K2: > Power< 11 W, Current ~ 88 mA > Power> 11 W, Current ~ 229 mA > > This makes sense to me because the KPA100 is providing power to the KAT100-2 > now, which apparently draws a lot less current than the K2 plus options. > > Here's what doesn't make sense to me: > Turning on the fan now that it's in the KAT100-2 does not increase the > KPA100's current draw at all, but it makes the current draw of the K2 go up! > > The only connection between the K2 and the KPA100/KAT100 is the data cable > connecting the RS-232 ports. Is this data cable providing current to power > the fan?! If so, how do I factor all this into figuring out a target for > the bias current adjustment? Do I add 400 mA to the 229 mA value and be > done with it? > > Thanks for straightening me out!! > > 73 > > N5BCN - Brian > > > > ----- > K2 #6800 KPA100/KAT100-2, KSB2, KAT2, KIO2, K160RX, KNB2, KAF2, LP-PAN/K2 w/ > Pre-amp, SignaLink USB > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/K2-Remote-KPA100-Bias-Current-Adjustment-tp6350558p6354410.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
