Re: [Elecraft] K2/100, KAT100 strange tuning problem
Bob, There is nothing unique to 40 meters in the KAT100, *but*. Behavior like that *could* be related to a parasitic oscillation in the KPA100. The parasitic usually revealed itself during a TUNE operation with the KAT100 also installed. The KPA100 T/R switch was re-designed to address that very problem. If your KPA100 was ordered before last December, it has the old T/R switch in it, and can have the parasitic problem on 40. I suggest you promptly obtain the KPA100UPKT and install it in your KPA100. 73, Don W3FPR Solosko, Robert B (Bob) wrote: Hello All, I hope that someone can suggest where to start tracing down a rather strange tuning problem that cropped up in the middle of working the IARU on Saturday. The short description is that the K2/100-KAT100 stopped tuning in AUTO mode when in high power mode on 40 meters. Here's some of the details: 1 - Tuning with the K2/100 and KAT100 on 40 meters has worked fine since I completed the KPA100 (rev. D) 6 months ago. 2 - I had no problems tuning for about the first 10 QSOs on 40m, and then the rig suddenly wouldn't tune at all when in high power mode (there were no lightening strikes during that time) - then tuning became erratic. 3 - Tuning worked fine when the power was reduced to low power mode: all I had to do was reduce the power just to the point where the power LEDs on the KAT100 switched from high power to low power and everything worked fine - then increasing the power just to the point where the power LEDs on the KAT1200 switched from low power to high power and the KAT100 wouldn't tune at all. ___ 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
RE: [Elecraft] K2/100, KAT100 strange tuning problem
Thanks Don... My KPA100 was ordered in December and is Rev D, so it's the version with the 40m parasitic problem fixed (it doesn't have RFC 10 on the antenna connector that the earlier versions did)- I wonder if the change to Rev D didn't quite fix the problem. Rev. E came out shortly after I built my KPA100, but I don't know what changed from D to E. Are there other things that I should check? Thanks. Bob W1SRB -Original Message- From: Don Wilhelm [mailto:[EMAIL PROTECTED] Sent: Monday, July 16, 2007 11:17 AM To: Solosko, Robert B (Bob) Cc: elecraft@mailman.qth.net Subject: Re: [Elecraft] K2/100, KAT100 strange tuning problem Bob, There is nothing unique to 40 meters in the KAT100, *but*. Behavior like that *could* be related to a parasitic oscillation in the KPA100. The parasitic usually revealed itself during a TUNE operation with the KAT100 also installed. The KPA100 T/R switch was re-designed to address that very problem. If your KPA100 was ordered before last December, it has the old T/R switch in it, and can have the parasitic problem on 40. I suggest you promptly obtain the KPA100UPKT and install it in your KPA100. 73, Don W3FPR Solosko, Robert B (Bob) wrote: Hello All, I hope that someone can suggest where to start tracing down a rather strange tuning problem that cropped up in the middle of working the IARU on Saturday. The short description is that the K2/100-KAT100 stopped tuning in AUTO mode when in high power mode on 40 meters. Here's some of the details: 1 - Tuning with the K2/100 and KAT100 on 40 meters has worked fine since I completed the KPA100 (rev. D) 6 months ago. 2 - I had no problems tuning for about the first 10 QSOs on 40m, and then the rig suddenly wouldn't tune at all when in high power mode (there were no lightening strikes during that time) - then tuning became erratic. 3 - Tuning worked fine when the power was reduced to low power mode: all I had to do was reduce the power just to the point where the power LEDs on the KAT100 switched from high power to low power and everything worked fine - then increasing the power just to the point where the power LEDs on the KAT1200 switched from low power to high power and the KAT100 wouldn't tune at all. ___ 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
Re: [Elecraft] K2/100, KAT100 strange tuning problem
Bob, Since you do have early updated version of the KPA100 - there is one thing yet to check, and that is the value of C31. If it is not a .22 uf capacitor, it should be changed to the new value. Elecraft will supply one if you ask - the part number is E530295. The capacitor situation was not discovered until after the updated KPA100s began shipping. Under certain conditions the updated KPA100 will oscillate near 600 kHz with the lower value capacitor at C31. I know this is confusing - the older KPA100s had a 40 meter parasitic, likely caused by RFC10 while the newer version has this other oscillation problem if the bypass capacitor is not large enough. Similar outward behavior, but entirely different causes. BTW - the changes from 'D to E' were only to clean up the manual. There is only a loose link between the manual level and the hardware revision level. 73, Don W3FPR Solosko, Robert B (Bob) wrote: Thanks Don... My KPA100 was ordered in December and is Rev D, so it's the version with the 40m parasitic problem fixed (it doesn't have RFC 10 on the antenna connector that the earlier versions did)- I wonder if the change to Rev D didn't quite fix the problem. Rev. E came out shortly after I built my KPA100, but I don't know what changed from D to E. Are there other things that I should check? ___ 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
RE: [Elecraft] K2/100, KAT100 strange tuning problem
Thanks Don, That could be the problem - my Rev D manual says it .033uf. I'll check it out and see it that cures the problem. Thanks again. Bob -Original Message- From: Don Wilhelm [mailto:[EMAIL PROTECTED] Sent: Monday, July 16, 2007 12:32 PM To: Solosko, Robert B (Bob) Cc: elecraft@mailman.qth.net Subject: Re: [Elecraft] K2/100, KAT100 strange tuning problem Bob, Since you do have early updated version of the KPA100 - there is one thing yet to check, and that is the value of C31. If it is not a .22 uf capacitor, it should be changed to the new value. Elecraft will supply one if you ask - the part number is E530295. The capacitor situation was not discovered until after the updated KPA100s began shipping. Under certain conditions the updated KPA100 will oscillate near 600 kHz with the lower value capacitor at C31. I know this is confusing - the older KPA100s had a 40 meter parasitic, likely caused by RFC10 while the newer version has this other oscillation problem if the bypass capacitor is not large enough. Similar outward behavior, but entirely different causes. BTW - the changes from 'D to E' were only to clean up the manual. There is only a loose link between the manual level and the hardware revision level. 73, Don W3FPR Solosko, Robert B (Bob) wrote: Thanks Don... My KPA100 was ordered in December and is Rev D, so it's the version with the 40m parasitic problem fixed (it doesn't have RFC 10 on the antenna connector that the earlier versions did)- I wonder if the change to Rev D didn't quite fix the problem. Rev. E came out shortly after I built my KPA100, but I don't know what changed from D to E. Are there other things that I should check? ___ 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
