When I built my K2 a year and a half ago, I also had to decide between bare K2 vs KAF2 vs KDSP2, and went through the archives. In the end I went with the KDSP2, but some of the points I considered along the way:
Bare K2: - built-in IF filters do work very well, but I read some reports that strong stations nearby can produce some « blow-by », and that either the KAF2 or KDSP2 can help clean it up. - At some point, Elecraft may cease production of the K2, and if I leave my K2 bare, I may not get the chance to upgrade it later. KAF2: - cheap, very easy to use - for CW, reports seem to indicate it performs about the same as the KDSP2 - has a nice LPF stage that cuts down background hiss, seems to be better than the KDSP2 in this regard. Some people have added a KAF2-style LPF to their KDSP2 with good results. KDSP2: - much more configurable than KAF2 - has noise reduction feature, I thought this might come in handy if I have the K2 as a second radio, and have it sitting on my club’s SSB calling frequency. It does keep the radio very quiet, almost like a voice squelch. - also has automatic notch filter, in case I need it - can go very narrow. I had good experiences with the DSP filtering in my KX3, which was really effective in digging out some very weak sigs on our QRP net (although so far I have mainly used the K2 for rag chewing, haven’t really done any side-by-side comparisons with KX3) - Code for the DSP is open source, so might be fun to play with. However, I think the development kits are now out of production, and I think maybe the chip in my KDSP2 was not in a socket, but soldered directly to the board (someone correct me if I am wrong). So, there are some barriers to playing with the DSP code, and if I wanted to experiment in DSP techniques, a much easier way would probably be to use a generic PC with sound card and GNUradio or similar development environment. - KDSP2 chews a lot more power than KAF2, which may be an issue if you like to run off batteries. You can disable the KDSP2 through the menu, which significantly reduces but doesn’t eliminate the additional power draw. If you power-cycle the K2, the disable setting of the KDSP2 is forgotten, and the KDSP2 will become active again. - the KDSP2 is a lot more complicated to use than KAF2. This means you have more flexibility, and some people like having lots of settings to play with, so it can be a plus. But it can also be a minus as it can be hard to remember how to change some of the less commonly adjusted settings. Having said that, the defaults on the KDSP2 are usually fine. So, is the KDSP2 a worthwhile upgrade? For your SSB friend, I would say yes. For a primarily CW operator like yourself who already has a KAF2, it might be harder to justify. Is the upgrade cost-effective? Well, the KDSP2 is significantly more expensive than the KAF2, and it is a personal choice whether the extra value/fun brought by the KDSP2’s additional features warrants the additional cost. After all, it is a hobby :-) -- 73 de Matt VK2RQ On 5 novembre 2015 at 10:44:52 AM, David Inger (ingerassocia...@cox.net) wrote: A friend has a fairly recent K2 with the KAF2 audio filter option. He asked me to remove the KAF2, build the KDSP2 board and install it in his K2. This got me to thinking: I also have a K2 wiht the KAF2 installed. My friend works mainly SSB; I work main CW and digital modes. Is the DSP board a significant improvement over the bare K2 or even with the KAF2 installed (which seems to be tailored for CW reception)? In general, radios that I have owned with AF DSP have been pretty much a disappointment. So is the KDSP2 a worthwhile and cost-effective upgrade? 73 de K6SBA David in Santa Barbara, CA ______________________________________________________________ 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 Message delivered to matt.vk...@gmail.com ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
