On Thu, 18 Dec 2008 08:14:51 -0800, Joe Planisky wrote: >I recently added the 400 Hz >filter and so far, it makes virtually no difference EXCEPT in the case >where there's a strong signal within +/- 1 kHz or so of the station >I'm trying to work. Note that a "strong signal" might be another ham >station, a broadcast station, RFI, etc.
Yes. Remember that the IF in the K3 has EXTENSIVE IF filtering that perform the function of crystal filters in older radios. Those filters can be adjusted (front panel knob) to virtually any bandwidth between 50 Hz and 6 kHz, and are the equivalent of a selectable filter bank of 20 or more expensive filters! The roofing filter simply sits IN FRONT OF these IF filters. It protects them from overload, AND provides additional skirt selectivity. The radio works fine for routine use with nothing more than the stock 2.7 kHz roofing filter. The roofing filters simply improve performance under difficult conditions. I own two K3s, one with 400 Hz and 1.8 kHz filters, the other with only a 400 Hz filter. I operated from two QTHs during the SSB weekend of Sweepstakes. At one QTH I had the 1.8 kHz filter, at the other I did not. The 1.8 kHz filter helped, but I was still quite happy with the radio that didn't have the 1.8 kHz filter. 73, Jim 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
