On Wed, 27 Apr 2005 10:50:58 -0500 (CDT), [EMAIL PROTECTED] wrote: >Two issues. First, I noticed RF on 160m to 40m when using the >microphones into the Rigblaster.
Most ham gear, including the K2, has what is known in the pro audio world as a pin 1 problem at its mic and control inputs. I don't know about the Rigblaster, but I would be surprised if it doesn't also have the problem. The RIGHT place to connect the shield of any cable is the chassis, not the circuit board (often called "mic ground" or "control ground"). See my website for applications notes about this. http://audiosystemsgroup.com/publish.htm Also see AES48, an international standard that addresses this issue, and includes a tutorial annex (that I helped write). http://www.aes.org/publications/standards/courtesy.cfm?ID=44 I have fixed the pin 1 problems by doing three things. First, I have added a short jumper between the mic jack and the chassis, and extended it to the shell of the headphone jack. Second, I make all of my shield connections to the shell of the mic connector. Third, I've replaced the "stock" RS232 cable with shielded CAT5. That shield, AND the returns of all the control lines, go to the shell of the DB9 connectors at both ends (the computer end and the K2 end), and NOT to pin 5. Before I made this change, my computer would lock up at 10 watts. Now I can use the K2 drive my Titan at 1 kW with no problem. Jim Brown K9YC _______________________________________________ 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
