On Mon, 4 Jul 2005 21:18:34 -0400, [EMAIL PROTECTED] wrote: >Hi I was wondering if there would be a problem using a 25 foot length of >cable from my K2 to the computer.
If you're going to run a longer cable, I STRONGLY recommend using twisted pair for the connection between the computer and the K2. The best solution is shielded CAT5; the second best solution is unshielded CAT5, or two runs of braid-shielded twisted pair. This will do two things. First, the twisted pairs will reduce the susceptibility of both the K2 and the computer to "RF in the shack" problems. Second, CAT5 cable has very low capacitance, which allows RS232 to work for longer distances. To gain the benefits of the twisting, use one pair (orange and orange/white, for example) to connect pin 2, with orange to pin 2 and orange/white to pin 5. Likewise, green to pin 3, green/white to pin 5. The overall shield should go to the DB9 shell on each end, not to pin 5. If you are using UN-shielded twisted pair, connect the return of each pair to the DB9 shell, NOT to pin 5. This puts a "band-aid" on pin 1 problems on each end. These techniques solved a nasty RFI problem for me that was causing my computer to grind to a halt at about 10 watts out to a long wire antenna that ended in the shack and ran right past the RS232 cable. Now I can run the K2/100 with my Titan amp at full power with no RFI problems. For more about pin 1 problems, see my website. http://audiosystemsgroup.com/publish 73, Jim Brown K9YC _______________________________________________ Elecraft mailing list Post to: [email protected] 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
