Dave, I would believe you are experiencing ground loop problems rather than feedback - yes, groundloops can introduce feedback of a type, but here in ham corcles we usually relate feedback to the RF type. Check by operating into a dummy load - if it persists, it is ground loop problems and not RF feedback.
When you transmit (either keying or SSB speech), there is a varying load on the power supply - that varying load translates into a small varying voltage drop on the power supply leads which can couple into the external speaker (which I figure is an amplified speaker). Use a separate power supply for the speaker and things may tame down a bit. Check the resistance of the entire power wiring to the KPA100 (including the DC return (ground) lead) and make sure that resistance is very low (in the milliohm range), and be certain the connections to the power supply are tight and low resistance. 73, Don W3FPR > -----Original Message----- > > I have a significant feedback problem with my K2/KPA100. When > transmitting there feedback (sounds as clear and as loud as a PA system) > through an attached external speaker. The only partial solution I have > found is to use a sea rate power supply for the K2 and NOT connect the > power supply to ground. This makes a noticeable reduction in the > feedback. However, as soon as I attach the power supply to ground the > feedback returns. It seems there should be a solution other than not > connecting the power supply to ground. > Suggestions and help will be gratefully appreciated. > > Dave Fleming KB3HCL > -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.441 / Virus Database: 268.18.2/692 - Release Date: 2/18/2007 4:35 PM _______________________________________________ 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
