Chuck, The full 'equation' also depends on your exact filter center IF frequency. It is better to use Spectrogram which provides a visual display of the filter passband placement, and you can set things optimally for any pitch that you desire. There are instructions within the K2 Dial Calibration article on my website http://w3fpr.qrpradio.com and also info at the Elecraft website. You can download the last freeware version of Spectrogram from Tom Hammond's website www.n0ss.com - that version has more than adequate capability for setting the K2 filters and BFO frequencies.
If you want to try a 'formula', I would suggest 2 steps - to change the BFO frequencies by 200 Hz, for each CW/CWr pair of frequencies, increase the lower frequency by 0.2 kHz and decrease the higher frequency by 0.2 kHz - then as a second step - If your crystal set was marked 3.6 (the most common), do nothing, but if it was higher (3.7 or 3.8), reduce all the frequencies above by 0.1 or 0.2 kHz and if your crystal set was 3.4 or 3.5, increase all the frequencies above by 0.1 or 0.2 kHz. Even so, you may be off by up to 100 Hz since the real center frequency will vary from crystal set to crystal set - Elecraft matches the crystals to 10 Hz, and the markings on the crystal bags are only to the nearest 100 Hz. Note that you can achieve better filter passband placement with Spectrogram than with just using the frequency settings listed in the manual for this reason alone. By far, the easiest and most accurate is to use Spectrogram after you complete the K2. At the point where you can receive 10 MHz WWV, you can accurately set the 4 MHz reference oscillator and all the filters so you achieve not only proper filter settings but good dial calibration as well. My website article tells you how to achieve all that with no equipment other than a computer with a soundcard, a stereo cable to connect the K2 to the soundcard and the K2 internal frequency probe. Once you have the filter settings correct for your purposes, write down the settings in case they are ever wiped out (by a Master Reset for instance) - you can restore the correct settings quickly. 73, Don W3FPR > -----Original Message----- > > The receiver sounds great, and compares favorably with my Ten Tec > Omni 6 loaded with INRAD filters. > > When doing the BFO calibration, I followed the recommended > settings, which I understand are based on a 600 Hz pitch. I like > to use narrow filters at a 400 Hz pitch. I'd like to set up for > the following filter sequence: 600, 400, 300, 150 Hz bandwidths. > > Is there a formula I can use to calculate the BFO frequencies I > need for CW normal and reverse to get the pitch and bandwidths I > want? Have others produced their own charts or lists of > customized BFO settings ? I apologize if I've missed something > in the manual or in the list archives. > > 73, > Chuck NI0C > -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.430 / Virus Database: 268.15.6/565 - Release Date: 12/2/2006 9:39 PM _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
