K3 filter/DSP selection?
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Hello, I have a K2 and am considering selling it to fund a bare bones K3. However, what I find awkward about the K2 is the way the cw filters (I only do cw) and the DSP filters are selected ... too much button pushing to get the bandwidth I need and if I go past the best setting I have to scroll all the way thru again. Plus no easy way to activate DSP noise reduction unless I have it pre-programmed. So I'm trying to understand how this is accomplished on the K3. I'd love to have a knob to control the filter and DSP bandwidth, a pushbutton to activate DSP, and another pushbutton to activate DSP noise reduction. I've looked thru the K3 operating manual but am not exactly following it. Could someone please shed a little light on how the K3 performs this and if they find it user friendly? thanks in advance. chuck af4xk ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Chuck
Properly set up in the menus, you just dial the bandwidth you want and the roofing filters automatically kick in where they are called for. One knob to twist and it all happens with a graphical representation on the screen. Couldn't be easier. Buck k4ia K3 #101 In a message dated 6/4/2009 8:07:01 P.M. Eastern Daylight Time, [hidden email] writes: Hello, I have a K2 and am considering selling it to fund a bare bones K3. However, what I find awkward about the K2 is the way the cw filters (I only do cw) and the DSP filters are selected ... too much button pushing to get the bandwidth I need and if I go past the best setting I have to scroll all the way thru again. Plus no easy way to activate DSP noise reduction unless I have it pre-programmed. So I'm trying to understand how this is accomplished on the K3. I'd love to have a knob to control the filter and DSP bandwidth, a pushbutton to activate DSP, and another pushbutton to activate DSP noise reduction. I've looked thru the K3 operating manual but am not exactly following it. Could someone please shed a little light on how the K3 performs this and if they find it user friendly? thanks in advance. chuck af4xk ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html **************Limited Time Offers: Save big on popular laptops at Dell (http://pr.atwola.com/promoclk/100126575x1221354145x1201369495/aol?redir=http:%2F %2Fad.doubleclick.net%2Fclk%3B215221161%3B37268813%3By) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by callen1155
Chuck,
The K3 filtering (both IF and DSP) is quite different than the K2 - in fact, there is no comparison. Bear with me and I will try to explain. The K3 will control the filters with 2 knobs - the SHIFT/LO-CUT and the WIDTH/HI-CUT. The K3 does all its ultimate filtering in DSP (at a 15 kHz DSP IF), and so DSP must be active all the time (it is doing all the work of both filtering and demodulation as well as a number of other tasks). The 8MHz IF filters in the K3 are "roofing filters" whose main task is to keep very strong signals out of the ADC at the front end of the DSP. The DSP itself can handle signals well above S-9 + 30, and has its own AGC (normal or DSP AGC) for signals of normal strength, but the ADC has its limits and would cause bad signal distortion if overloaded. However, the K3 has an additional hardware AGC at the 8MHz IF that will activate only when the signals *inside* the roofing filter passband are stronger than S-9+30. The result is that *if* that hardware AGC is activated, it will cause signal "pumping" (following that strong signal). The solution is to use a more narrow roofing filter to narrow the passband that the ADC input to the DSP is exposed to. The additional roofing filters (if installed) are automatically switched in when you narrow the DSP bandwidth. No button-pushing is necessary. Just move the WIDTH knob and it will happen. What all this roofing filter stuff means for you is that the stock basic K3 with only the 2.7 kHz roofing filter will do a great job unless you have an extremely strong undesired signal within that 2.7 kHz bandpass. For normal operation, that one roofing filter is likely to be sufficient, but if you are operating in contest times or chasing DX where the possibility that there will be several strong stations near the frequency of the weak signal you are trying to copy, you will want additional roofing filters installed to keep the hardware AGC from activating. If initial cost is a consideration, my recommendation is to first use the K3 with only the stock roofing filter, then after a bit of operating, you will know whether and when you need additional roofing filters. Considering wider bandwidth roofing filters: If you are considering ESSB or AM transmitting with the K3, then you need the 6 kHz roofing filter If you are considering FM operation, you will need the 13 kHz roofing filter. 73, Don W3FPR chuck allen wrote: > Hello, > > I have a K2 and am considering selling it to fund a bare bones K3. However, what I find awkward about the K2 is the way the cw filters (I only do cw) and the DSP filters are selected ... too much button pushing to get the bandwidth I need and if I go past the best setting I have to scroll all the way thru again. Plus no easy way to activate DSP noise reduction unless I have it pre-programmed. > > So I'm trying to understand how this is accomplished on the K3. I'd love to have a knob to control the filter and DSP bandwidth, a pushbutton to activate DSP, and another pushbutton to activate DSP noise reduction. I've looked thru the K3 operating manual but am not exactly following it. > > Could someone please shed a little light on how the K3 performs this and if they find it user friendly? > > thanks in advance. > chuck > af4xk > > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.339 / Virus Database: 270.12.53/2154 - Release Date: 06/04/09 05:53:00 > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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