On Tue, 29 Dec 2009 01:23:42 -0600, Jim Miller KG0KP wrote: >My selection was for the 250 and I am very happy with it >and actually see the 200 as being RARELY used if at all. It is narrow >enough that if the responding cw station is off frequency, you will NOT hear >them at all.
Let's clarify a few things about these very narrow roofing filters. First, when you install any roofing filter, you tell the K3 what bandwidth it is, what slot it's in, and how much passband attenuation it has (so that the K3 can add gain to correct for it). Second, as you operate, contesting or otherwise, a good operator will constantly be readjusting bandwidth and RIT to respond to callers. My CW roofer is 400 Hz, and I usually operate with an IF bandwidth of 250-350 Hz in CW mode, so it is virtually always engaged. When the going gets rough, whether because he's weak or there's QRM, I'll quickly narrow up the IF to pull him out of the mud. The time you want that 200 Hz roofer is when there's strong QRM within a few hundred Hz of your frequency. This is a "5% of the time" filter, not a general purpose filter. It's for the guy who's a serious contester, his rig is bought and paid for, and he's got a few bucks laying around. The 400 Hz and 500 Hz filters are good general use CW filters. When I bought my K3s, I put the 400 Hz filters in the next to the last filter slots, figuring that someday I might want the 200 Hz filters. And someday I still might. I sure did Sunday morning, trying to copy JT1CO within 200 Hz of a Seattle area station during the 160M Stew Perry contest. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
