According to Icom (who has it on some of their rigs): "The APF changes the audio frequency response by boosting a particular frequency to enhance a desired CW signal... The peak frequency can be adjusted"
So this is an adjustable frequency audio filter such as we've used for the past 3/4 century. As Doug, KR2Q, noted, the K3 is capable of a 50 Hz bandpass. That's about as narrow as a CW signal being keyed at 20 or 30 wpm can be fit into. Narrower will attenuate the CW sidebands so the dots and dashes start "slurring" together. I've used an audio filter many times and found them of very limited value to me if the receiver has a decent I.F. bandpass characteristic. That said, if it it's reasonable to implement, people want it, and it can be switched out, I'm all for it. Ron AC7AC ______________________________________________________________ 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
