I prefer the 500Hz filter over more narrow ones. Less IMD on the RX signal.
Bob, K4TAX Sent from my iPhone > On Dec 31, 2017, at 9:55 PM, K9MA <[email protected]> wrote: > > I use similar settings for CW, with both filters. I haven't tried DSP > bandwidth of 250 Hz with the 400 Hz crystal filter, but based on the filter > characteristics, I don't think it would make much difference. Also, the 250 > Hz filter drifts around so much with temperature that it's hard to keep it > centered properly. > > Compare the responses here: > > http://www.elecraft.com/K3/K3_filter_plots.htm > > Anyhow, all I'm saying is that even for a pretty hard-core CW contester, I'm > not sure the narrow filter is worth the investment. > > Now, my previous rig, an FT-1000D, which is inferior to the K3 in almost > every other way, actually has better skirt rejection on CW, but that's with > cascaded crystal filters, both of either 500 or 250 Hz bandwidth. I'm not > sure that's because of an inherent limitation of the K3 DSP, or just the > filter algorithm chosen (perhaps to limit latency?). > > 73, > Scott K9MA > > >> On 12/31/2017 21:32, [email protected] wrote: >> 400Hz is definitely my favorite CW and RTTY filter. I also use the 250Hz >> roofing filter (switched in at 350Hz) when the QRM gets bad, what document >> shows that this offers little improvement? >> >> John KK9A >> >> >> K9MA wrote: >> >> Assuming it's for a K3(s), I don't think you will find the 250 Hz filter >> very useful. The response that both Elecraft and I measured shows that >> the narrow filter really isn't much better. Were I to do it again, I >> would only use the 400 Hz ones. >> >> 73, >> Scott K9MA >> >>> On 12/31/2017 17:02, doug dietz wrote: >>> Guys >>> i ordered a 400hz filter by mistake. I have use for a 200h or 1k, 18.k >>> What ya got >>> doug49707 at gmail.com Doug WD8Z >> ______________________________________________________________ >> 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] > > > -- > Scott K9MA > > [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] ______________________________________________________________ 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]
