APF
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The subject line should read APF of course, sorry!
Sam, thank you for the tips on APF. One remark though: "Switching between the two filters is as easy as HOLDING the SHIFT knob in." I suppose you mean the WIDTH knob... 73 Richard - HB9ANM ______________________________________________________________ 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
Richard - HB9ANM
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Sam;
Your explanation is really good Sam, but it seems that something doesn't follow for me. cut...======================== >Turn on the RIT control (tap the RIT button). Next, lower the RIT >frequency -20 Hz. (You must have CONFIG:PB CTRL in the config menu set >to .01 to move in 10 Hz steps). If your pitch is set to 500 Hz, then the >tone of the CW should now be 480 Hz. Next, turn on the APF by HOLDING >the DUAL PB button. Adjust the APF using the SHIFT Fc Knob (now APF >control). Move the APF down -20 Hz to match the CW signal. Once you have >the signal in the center of the new 480 Hz tone you should hear that the >CW signal pops up about 5 or 6 dB.... >Ok, I did this, first setting my pitch at 500 Hz, which actually even cut out some ringing! I got the station centered, etc., turned RIT down -20, activated APF, but then the problem began. I am not sure what the "SHIFT Fc Knob" is--if it is just the regular "Shift-Lo" knob then this doesn't do anything for me when I turn it. Is this the right knob? Do I need something turned on in CONFIG for it to work? I have had my K3 a little more than 1yr., and I sort of remember that MAYBE I could move the passband once at first, but I my be remembering bad! Thanks for the help. 73 Scott AA0AA; XE1/AA0AA ______________________________________________________________ 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 |
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1st of all let me be clear, I was merely quoting from my notes that I
had copied from a post (or web site?) that Dusty K3WC wrote that said yes it was the Shift knob Dusty was speaking of calling it the Shift Fc (frequency) knob when I turn mine it says (in the VFO B window) APF *0.48 (my pitch is set for 480hz) so I have to turn the Shift knob until I see it say APF 0.46 meaning it's at 460hz or 20hz below my default pitch of 480hz sorry I'm not as good as Dusty at explaining these things sm On 12/7/2013 7:04 PM, Scott Monks wrote: > Sam; Your explanation is really good Sam, but it seems that something > doesn't follow for me. > > cut...======================== > >> Turn on the RIT control (tap the RIT button). Next, lower the RIT >> frequency -20 Hz. (You must have CONFIG:PB CTRL in the config menu >> set to .01 to move in 10 Hz steps). If your pitch is set to 500 Hz, >> then the tone of the CW should now be 480 Hz. Next, turn on the APF >> by HOLDING the DUAL PB button. Adjust the APF using the SHIFT Fc >> Knob (now APF control). Move the APF down -20 Hz to match the CW >> signal. Once you have the signal in the center of the new 480 Hz >> tone you should hear that the CW signal pops up about 5 or 6 >> dB.... Ok, I did this, first setting my pitch at 500 Hz, which >> actually even cut out some ringing! I got the station centered, >> etc., turned RIT down -20, activated APF, but then the problem >> began. > > I am not sure what the "SHIFT Fc Knob" is--if it is just the regular > "Shift-Lo" knob then this doesn't do anything for me when I turn it. > Is this the right knob? Do I need something turned on in CONFIG for > it to work? > > > I have had my K3 a little more than 1yr., and I sort of remember that > MAYBE I could move the passband once at first, but I my be > remembering bad! > > Thanks for the help. 73 > > > Scott > > AA0AA; XE1/AA0AA -- GB & 73 K5OAI Sam Morgan ______________________________________________________________ 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 |
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In reply to this post by Scott Monks
IMHO K3WC's APF suggestion is WAY TOO COMPLICATED. I use APF virtually all the time and never use RIT, SHIFT, etc. Just HOLD DUAL PB to actuate APF and use the VFO to zero beat. COARSE (10 Hz) VFO steps is usually close enough but you can switch to FINE (1 Hz) if necessary for ultra weak signals. I also strongly endorse N6KR's suggestion below:
"I suggest setting the passband width to about 250-300 Hz when using APF." This is extremely important since bandwidths too narrow will introduce additional ringing to the APF which already borders on ringing. I actually use a 200 Hz XFIL but set to actuate at DSP 400 Hz. With WIDTH set to 400 Hz, the signal first goes through the relatively broad (4.0 shape factor) 200 Hz XFIL, then a 400 Hz DSP and finally the narrow APF. This makes the cascaded XFIL/DSP look more like 250 Hz, reduces ringing, still allows you to hear off-frequency callers (although attenuated) and helps your ears discriminate weak signals from noise by providing a wider background sample of noise. 73, Bill W4ZV
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I too often use APF on both the K3 and KX3. I prefer tuning APF with 1
Hz steps. The KX3 enables 1 HZ steps when APF is enabled. I miss that feature with the K3. A new feature request; when in SPLIT and VFO A at 1 Hz, leave VFO B at 10 Hz. John KN5L On 12/08/2013 04:48 AM, Bill W4ZV wrote: > I use APF virtually all > the time and never use RIT, SHIFT, etc. Just HOLD DUAL PB to actuate APF > and use the VFO to zero beat. COARSE (10 Hz) VFO steps is usually close > enough but you can switch to FINE (1 Hz) if necessary for ultra weak > signals. ______________________________________________________________ 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 |
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In reply to this post by Bill W4ZV
I agree with Bill. There's no need to fiddle with the RIT control. I think Dusty's original suggestion implies that he found the APF to be more effective at a slightly lower frequency (20Hz lower) than his nominal CW pitch setting. This may be true but it can be more easily accomplished by tuning the signal a bit lower in frequency with the main VFO. Then just tweak the APF center frequency with the SHIFT knob.
Dusty's suggestion may appeal to some because it doesn't shift your transmit frequency 20Hz off of zero beat. In the grand scheme, however, 20Hz off of zero beat is hardly noticeable. The important thing here is to play with the APF and learn how to use it. You don't have to wait for weak signals. You can experiment with medium strength signals. Then once you get the hang of it you'll be good to go when trying to pull out a weak one. But don't expect the APF to pull them all in. The APF has its limitations. 73, Mike K2MK
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In reply to this post by Richard Squire - HB9ANM
Hi all, and Sam;
>________________________________ > >Message: 7 >Date: Sat, 07 Dec 2013 19:38:20 -0600 >From: Sam Morgan <[hidden email]> >To: "[hidden email]" <[hidden email]> >Subject: Re: [Elecraft] APF >Message-ID: <[hidden email]> >Content-Type: text/plain; charset=ISO-8859-1; format=flowed > >1st of all let me be clear, I was merely quoting from my notes that I >had copied from a post (or web site?) that Dusty K3WC wrote > >that said >yes it >calling it the Shift Fc (frequency) knob > >when I turn mine it says (in the VFO B window) >APF *0.48 (my pitch is set for 480hz) >so I have to turn the Shift knob until I see it say APF 0.46 >meaning it's at 460hz or 20hz below my default pitch of 480hz >Sam, you are doing fine in explaining, Thanks! I searched around on my hard drive and found the piece that Dusty wrote--I also had downloaded it and saved it but I didn't mark where I got it, just his call. The problem WAS, that using the shift in APF wouldn't move anything (only showed FC *0.50 in the VFO B window). I went to Fred's book and found that Dual PB needed to be set to APF in the CONFIG (mine some how got set to "nor"). Putting that right has completely changed things! I had about given up on using APF but now it works as it should and I feel good! Thanks for helping me straighten that out, Sam and Bill, W4ZV. Now I can get back to trying to get a valid contact with T32RC--I have worked them 3 times on CW and they have never logged my call correctly even though I thought they had it. Thanks all--as always, good help here! 73 and good DX, Scott AA0AA; XE1/AA0AA ______________________________________________________________ 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 |
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