Thanks Don. I will have to experiement more using the DUAL PB. I have that button set up for APF right now. --Ed—
Sent from Mail for Windows 10 From: Don Wilhelm Sent: Wednesday, February 20, 2019 6:00 PM To: Ed G; [email protected] Subject: Re: [Elecraft] K3 XFIL Button Ed, Keep in mind that the DSP provides the ultimate filter width, the one situation you asked about - roofing filter wider than the DSP filter is already present - just set the filter configuration to "lie" about the actual filter width, and the roofing filter will be switched in at a DSP width that is wider than the roofing filter. The other (DSP filter wider than the roofing filter) does not make much sense to me. Yes, in the filter configuration, you can tell the K3 that the (for example) 400Hz filter is really a 600 Hz filter, then you have accomplished what you desire. I do not have much use for the XFIL button and never use it. I let the Width control (or HiCut/LoCUT for SSB) switch in whichever roofing filter is appropriate and consistent with the DSP width I have selected and it works well. The DSP filter width is a "brick wall filter" and you will not be able to hear signals outside that bandwidth. Keep in mind the purpose of the roofing filters. In a crowded band, the roofing filters keep strong adjacent stations from activating the Hardware AGC which is there to protect the ADC from overloading. In other words (again using the 400Hz roofing filter example), if you have the DSP bandwidth set at 300Hz centered on [150Hz plus sidetone pitch = 750 Hz], and you have a very strong signal at 850 Hz, you will not hear the strong signal because of the DSP width, but it will activate the hardware AGC causing the AGC to 'pump' and the receiver sensitivity will be reduced as a result of that 'pumping' - even though you cannot hear the signal. As an alternative, you might want to try turning on DUAL PB in the menu which will give you a wider passband that is attenuated from the narrow filter peak (or focus). I believe that will give you what you seek. 73, Don W3FPR On 2/20/2019 5:15 PM, Ed G wrote: > Seems like the K3 XFIL button essentially does the same thing as the DSP > width knob. That is, depending on how the user has set up the filter > configuration, both DSP and filter selected are pretty much automatic and > linked together. Adjusting the width knob will result in a particular crystal > filter being selected, and similarly, using the XFIL button to select a > filter will automatically adjust the DSP setting. > > On occasion, I would like to be able to use a wider DSP setting with a > narrower crystal filter, or a narrower DSP setting with a wider crystal > filter. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ______________________________________________________________ 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
