K8XF writes ... "As a cw opr ... I would like to know ..."
Hi Mike, 1) If you are considering using the optional sub-RX for diversity reception, then you might prefer INRAD's 8-pole filters simply because they are already matched, i.e. their center frequencies are much tighter than Elecraft's 5-pole filters. (We're talking about tens of Hz for the INRAD filters compare to more like a kHz for the Elecraft filters!) 2) All SSB, CW, and digital TX is done via the "normal" SSB filter (either 2.8 kHz 8-pole or 2.7 kHz 5-pole). Thus many guys will choose the 8-pole 2.8 kHz filter, that it might produce a slightly cleaner transmitted CW signal. This is more important if you run 500 Watts as opposed to 10 Watts. 3) Due to the K3's architecture, it is sometimes desirable to have a crystal filter whose width is close to your DSP passband setting. Specifically when working a weak signal that's close to a strong one. Otherwise, if the strong signal is inside the passband of your crystal filter, it can cause AGC pumping and render the weak signal unreadable. Your needs in this regard will depend on local band conditions. 4) INRAD's 250 Hz filter is actually closer to 370 Hz wide at 6 dB down, while their 400 Hz filter is about 435 Hz wide. That's a difference of roughly 21%, which IMHO is too similar to justify installing both. 5) In addition to the INRAD CW filters offered by Elecraft (1000 Hz, 400 Hz, and 250 Hz), INRAD also offers 500 Hz via their website. See http://www.inrad.net/home.php?cat=140 6) In addition to the INRAD CW filters offered by Elecraft and INRAD, WB2ART and I also offer 700 Hz. Note that this is a special order item which is currently in stock, but which usually entails a preorder waiting list and a 14-week manufacturing lead-time. See http://www.unpcbs.com 7) I suspect that guys who have the P3 (panadapter) tend to set a tighter passband and in turn prefer narrower crystal filters. 73, Gary KI4GGX webmaster, unpcbs.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
