Thank you Don. I think the most confusing part of all was, I was looking for various width settings for the ssb filters. Eventually I came to realize that I had to use the other filters for reduced bandwidth for ssb. After that dawned on me it was relatively easy. Or perhaps I still have not got it correct. Still can't get the display on frequency. I guess I need a decent freq counter. Can't seem to manage with wwv.
cheerio and 73. Garry On Thu, Feb 11, 2010 at 8:52 PM, Don Wilhelm-4 [via Elecraft] <[email protected]> wrote: > Garry and all - at least those who are building new K2s. > > Yes, the filter setup is a bit "tricky", especially when using filter > widths wider than 1.00 kHz. The reason is in the varactors that have > shipped with the more recent K2 kits. What that means is that a filter > width that is indicates as 2.00 kHz wide on the K2 may actually be 2.5 > kHz wide (this is not exact, it all depends on the varactors). The > result of this is that the LSB filter settings listed in the manual will > be about right, but the USB settings will be way off. In other words, > the manual settings will give you a workable filter for the lower > sideband response, but will not work for the upper sideband (USB, RTTYr, > and CWr) settings. (NOTE: the OP1 filter width is not affected by the > varactors - there are no varactors on the KSB2 board). > > The only cure I know is to use Spectrogram or another audio spectrum > analyzer to measure the actual width of the filter (in LSB or CW - not > CWr - or RTTY - not RTTYr). When you use LSB, CW or RTTY, you should > be on the lower sideband, and you can change the width without much > movement of the lower end of the passband frequency. After getting the > filer width as you like it, then refine the low frequency end of the > lower sideband filter (by changing the BFO setting) and then set the USB > BFOs to properly place the sideband. > > If you want specifics on how to set the filters, look at part 3 of the > article on K2 Dial Calibration at my website www.w3fpr.com (while you > are there, you may just want to go through the entire K2 Dial > Calibration procedure which includes adusting the filters. > I have not yet updated the webpage information to include how to handle > this "varactor problem", but since you can see the passband width on the > Spectrogram display, it should be obvious. Just adjust the width of the > filter until the actual width is what you want, and use the K2 display > only as a relative indicator. > > 73, > Don W3FPR > > 2rGarry wrote: >> Congrats on the K2 receiving on 40. It's only a month or so back that I >> finished mine so easy for me to remember the thrill of hitting the switch >> and having it come up working. I used mine on cw for a week or so then >> went >> on to the ssb board which allows digital modes as well as phone. Still >> using it qrp here and may never buy and build the power amp as I have been >> having a blast with it even on qrp. >> >> If you chose the ssb option perhaps you will find as I did that the >> directions for setting up the filters are somewhat confusing however it >> will >> all fall into place eventually. >> >> Cheerio, maybe hear you on the air sometime. >> >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > > ________________________________ > View message @ http://n2.nabble.com/K2-working-on-40M-tp4554916p4559453.html > To unsubscribe from Re: K2 working on 40M, click here. > -- View this message in context: http://n2.nabble.com/K2-working-on-40M-tp4554916p4563834.html Sent from the [K2] mailing list archive at Nabble.com. ______________________________________________________________ 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
