It's been 2 years since there were complaints on this forum about the K3 auto-notch. Apparently it was never fixed.
The other day I was working a Ham in Tel Aviv when a carrier came on and covered his signal. The Auto notch worked well but the guys voice was very distorted. To me that's unacceptable. This year at the Dayton Hamvention I talked to someone from Elecraft about the DSP problems and he agreed that the auto notch needs some improvement. I think he was a the product manager. Back in the early 90's I worked with another Engineer on a project we called "The Hamblaster". I published two articles in QEX (October 1991 and January 1992). We developed a PC based sound card that connects to the receiver's audio and performed, among other things, an auto-notch and noise reduction (NR). In our DSP software, the auto-notch was generated by summing the inverted NR output to the input signal. Whether it's a noise reduction or an auto-notch we still used a software algorithm called the LMS (Least Means Square). Most Ham transceiver use the same LMS algorithm and I never heard distorted audio when the notch was engaged. That's especially true with Yaesu, Icom or Kenwood. I'm not sure about the other American brands but I bet they are OK as well. My second complaint is the K3's NR control. Most other manufacturers have an analog like control that simply changes the NR level. I don't understand the logic of having several steps from F1-1 to F4-4 and F5-1 (mixed) to F8-4 (mixed). I would rather have two separate settings. F0 to F9 for the level and if you want a to fiddle with the delay, D0 to D9 in the main menu. I think the level control on other radios is simply a mix of the input signal with the NR output and is similar to the K3's mF5-1 to mF8-4 To me it sounds as if there's a dynamic range problem on the K3 whereby the numbers in the math are over-ranging when the notch is engaged and is causing a "flat-topping" in the audio signal. But that's just a guess! I hope someone at Elecraft reads this and gets the ball rolling to fix the problem! Jack WA9FVP Willco Electronics [email protected] ----- Jack WA9FVP Sent from my TRS-80 :-) -- View this message in context: http://elecraft.365791.n2.nabble.com/Auto-Notch-Revisited-tp7591810.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
