Tom, I have the 1.8 filter in my old K3 #98 and have found over the years that I almost never use it. The DSP Width and Shift controls with the stock 2.7 filter have been adequate for my needs in all SSB contest conditions when using fast AGC. So, if I wanted a narrower filter for SSB, then the 2.1 would be the only one I would consider.
73, Henry - K4TMC On Wed, Dec 24, 2025 at 2:10 PM Jim Brown via Elecraft < [email protected]> wrote: > On 12/24/2025 8:43 AM, Tom Bowles via Elecraft wrote: > > I'm considering adding a 1.8 kHz for SSB and a 250 Hz for CW, but I've > read that the 250 Hz filter often measures wider in practice (around > 330-350 Hz) and may not be as sharp as expected. Has anyone experienced > this, and would you recommend it, or suggest alternatives like the 200 Hz > or 400 Hz instead? > > First, these are ROOFING filters to protect the DSP IF from overload > from very strong nearby stations. It is that DSP that sets the IF > bandwidth. I'm a serious contester, and have used K3s since 2008. The > 250 Hz 8-pole filter is great for CW. I found the 1.8 kHz filter too > narrow for SSB, and prefer the 2.1 kHz filter. If you work RTTY, the 2.8 > kHz filter has much better response than the stock 2.7 kHz filter, which > greatly reduces the incidental AM on transmit with RTTY. If you don't do > RTTY, it doesn't matter. > > 73, Jim K9YC > ______________________________________________________________ > 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] > ______________________________________________________________ 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]
