Don, Yes, I was mostly concerned with my 400 Hz filters, which are the narrowest I have.
I do have an XG2 that I won at Dayton--still un-assembled. And I can handle the procedure you outlined. Thanks for the response. Garry On 4/12/2010 4:27 PM, Don Wilhelm wrote: > Garry, > > The amount of the actual offset is small for the 8 pole filters. It > is not important on wide filters, but with the more narrow ones, it > becomes increasingly important - so yes, for maximum performance in > diversity mode (and only in diversity mode) setting the offset midway > between the measured offset of each filter is a prudent thing to do - > although I would not bother with anything wider than a 1 kHz filter - > the offset expressed as a percentage of the filter width is the > 'telling' parameter - 10 Hz at 2.8 kHz is only 0.34% which is > insignificant, but 10 Hz at 250 Hz is 4% which is significant. > > It is easy to determine the actual filter center (the K3 has the AFV > and dBV displays built-in) - just scan through the response to a > constant signal input level to the K3 to see where the -3 (or -6) dB > points are (the filter center is midway between those two points). > Ifyou do not have an XG2 or other signal generator, run another > transmitter into a dummy load and pick up an S-6 level signal with a > short 'antenna wire' on the K3. Nothing exotic is needed with a > little bit of thought put into what needs to be accomplished. > > 73, > Don W3FPR > > Garry Shapiro wrote: >> Apparently, from what has been previously discussed here, not all the >> 8-pole filters are "no offset" in practice and some models in >> particular might benefit from offset adjustments. And one should not >> forget that these filters are roofers. Unless money is no object, I >> would say to leave the stock filter in place and add another, >> narrower SSB filter. As to what its BW should be, there have been >> scads of opinions expressed on that subject, as well. >> >> Garry, NI6T >> >> On 4/12/2010 5:05 AM, David Ferrington, M0XDF wrote: >>> Since you seem to favour 8 pole, I'd say do it. You should be able >>> to get a rebate on the 2.8kHz against the 2.7kHz. >>> Also, if you are going to get the KRX3, it's simple to align the 8 >>> pole filters - otherwise you need to tell Elecraft what the offset >>> of your 2.7kHz is >> ______________________________________________________________ >> 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 >> > ______________________________________________________________ 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
