John, Is this a relatively new KPA100, or did you purchase an older kit from someone who never built it?
The reason I ask is because the older T/R switch design had elements that could cause parasitic oscillations near 40 meters, and often was most noticeable on SSB. If your KPA100 has blue toroid cores for L16 and RFC1, then it is the new design. If you have the new design, then did you fasten the shield directly to the SO-239 jack using the two solder lugs as instructed? These are important. Make a check - remove the KPA100 from the base K2, but keep it connected - in other words turn the KPA100 upside-down on a book or box to the right of the K2. Then try your SSB operation again (into a dummy load please, antennas are not consistent). If it works OK with the KPA100 upside-down, then look for causes of coupling from the KPA100 into the base K2, but if it still mis-behaves, we can look at other things. 73, Don W3FPR On 11/8/2010 6:15 PM, VK7JB wrote: > Hello again folks, > > Sorry about the barrage of posts from me. Just playing with my K2/100 #6998. > > I've noticed that when operating in SSB on 40m, requesting any power 15-20 > W and up will always give me 100W+ output, measured into a dummy load. > Voice peaks are higher and result in Hi Curr warnings occasionally. I can > reduce the power above this threshold only by changing SSBC to 1:1 (normally > run at 2:1 with my MH-2 mic) and winding the power out back to just on 11 W. > > CW and TUNE modes - all OK: power requested and power output track very > well on all bands, including 40m. > > Bands above 40m on SSB are not affected - I mostly work 20m SSB and haven't > noticed the power tracking issue there. ALC seems to control the power out > well there. > > I suspect the Tx chain gain on 40m is too high for the ALC to manage when in > SSB. > > Is there any way of making the ALC more aggressive on 40m SSB, without > affecting the other bands too much? I remember seeing a previous post about > this somewhere but haven't been able to find the details again. > > Any suggestions? > > 73, > > John > VK7JB ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
