I am starting to notice that the adjusting the BFO for a given bandpass response also shifts the frequency. Of course frequency shift is what a BFO setting is all about. I guess the K2 doesn't have an IF shift like most rigs. If I set the BFO for each filter width, to give the same frequency, what will happen to the bandpass response.
I have these questions because of my new KSB2 option. But I also noticed the problem with the CW filters in the CW mode. I can live with a little bit of shift on CW and SSB. But I can't really live with it on the digital modes. I understand from reading the KSB2 docs, that tx is always from the OP1 filter, including the RTTY mode. So it is essential that I get BFO on the other filters to match OP1 as close as possible. That probably means the crystal filter characteristics will determine the center frequency of the bandpass. Is this correct? The real question I have is how to adjust the frequency shift accurately. I have a idea to float. I have the XG1 signal source for 7040 kHz at S9. I can use MixW to measure the beat audio frequency down to 0.1 Hz. I assume I can set the BFO for each filter to the same audio frequency as OP1. I understand I may not be able to get right on the same frequency due to the resolution of DACs. I can correct the shift between tx and rx with MixW. But the frequency shift might change from filter to filter. Right now I've set the filter widths in RTTY mode for 2500, 1000, 500, & 250 Hz for starters. I set SSB for OP1, OP1, 2200, & 1800 Hz. Do I have a handle on the issue, or am I missing something? 73, Steve N6VL K2 #2289 _______________________________________________ Elecraft mailing list Post to: [email protected] 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
