Here is an operational scenario: You are CQing in the CQ WW CW contest. There are other loud stations CQing on either side of you. You have adjusted your SHIFT and WIDTH controls to eliminate the adjacent-channel interference while still, you hope, being wide enough to catch anyone calling you.
A weak station replies to your CQ, but he's some distance off your frequency, although still within your bandpass. You'd like to be able to put an audio peaking filter on his signal without affecting the rest of your setup. You don't want to change your sidetone pitch; that's a separate question for a separate discussion. You don't want to use RIT or CWT, because that will bring one of the adjacent loud signals into your bandpass. Anyway, the desired signal is too weak to trigger CWT. Likewise, you don't want to shift your main DSP filter bandpass (the "context"); you've got this set up for where you are and you don't want to change it just for this one 30-second QSO. If you didn't have an APF, you might try narrowing the DSP filter bandwidth, but he's far enough off-frequency that doing so would run the risk of losing his signal, meaning you would have to fiddle with both SHIFT and WIDTH to home in on him, and that takes time to do, plus more time to restore them after the QSO. What you would really like to be able to do is to adjust an audio peak filter's frequency so that it is on top of the received weak signal, but without affecting the context (your DSP shift and width, your sidetone pitch, or your transmit frequency - these should all stay where they were). My suggestion would be to use one of the buttons (DUAL PB seems to be a possible candidate here) to turn the APF feature on, and while the feature is on, the SHIFT and WIDTH controls would adjust the APF frequency and width (or Q) and would have no effect on the context filtering. RIT and SPLIT would still work normally, it's just SHIFT and WIDTH that would have been subverted to do the APF adjustments while the APF is on. If you really did want to adjust the context filter width or shift, you would have to turn APF back off to do so. Once the QSO with the weak station had been successfully concluded, you could either turn APF off, or else leave it on with its width adjusted to include the entire context bandpass, and carry on CQing. My 2c worth. 73, Rich VE3KI ______________________________________________________________ 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
