APF effectiveness...
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APF ringing and over powering...
I have had input from two Elecraft support fellows one of which was helpful. That being move the receiver off frequency (RIT) about 10Hz then adjust the APF center frequency to match. Some help - yes. But... The Elecraft implementation of APF in MCU 4.22 just before the current MCU 4.25 needs more work. The APF in the IC-781 from 1988/9 is much more effective with plenty of gain without ringing. The FT-1000 (early production only) and IC-7800 APFs are better than the K3's. The Yaesu MP series I have to admit, is useless. Elecraft either needs to tweak it for perhaps less gain and a little wider BW or give the user the tools to do it ourselves. I hope the folks at Elecraft will put some attention to this feature. it can be a powerful tool. I still find it amazing that this little 9.5 pound K3 sitting next to my 52 pound IC-7800 and 51 pound IC-781 is as good and in some cases better than either of those radios. Also nice is power consumption - listening on the K3 consumes only 33 watts with an Astron SS-30 while the two Icom's consume 100 watts each. 73, Bob - W6OPO ______________________________________________________________ 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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Hi Bob,
While agree that the APF could use a bit more gain ( I always end up turning up AF Gain once the APF is enabled), I find it leagues ahead of the APF in my ex-7700- which I believe had the same APF as the 7800. I even complained to Icom about its ineffectiveness. At the time I was running the 7700, I also had my Alpha Delta speaker system with its own APF- and there was no contest between the two. I thought perhaps there was a problem with my 7700's APF until I heard from others that also thought it was a useless feature on the 7700. Dale W4OP ----- Original Message ----- From: "Bob Lanning" <[hidden email]> To: <[hidden email]> Sent: Tuesday, January 25, 2011 3:11 PM Subject: [Elecraft] APF effectiveness... > APF ringing and over powering... > > I have had input from two Elecraft support fellows one of which was > helpful. That being move the receiver off frequency (RIT) about 10Hz > then adjust the APF center frequency to match. Some help - yes. > > But... > > The Elecraft implementation of APF in MCU 4.22 just before the current > MCU 4.25 needs more work. The APF in the IC-781 from 1988/9 is much > more effective with plenty of gain without ringing. The FT-1000 (early > production only) and IC-7800 APFs are better than the K3's. The Yaesu > MP series I have to admit, is useless. Elecraft either needs to tweak > it for perhaps less gain and a little wider BW or give the user the > tools to do it ourselves. > > I hope the folks at Elecraft will put some attention to this feature. it > can be a powerful tool. > > I still find it amazing that this little 9.5 pound K3 sitting next to my > 52 pound IC-7800 and 51 pound IC-781 is as good and in some cases better > than either of those radios. Also nice is power consumption - listening > on the K3 consumes only 33 watts with an Astron SS-30 while the two > Icom's consume 100 watts each. > > 73, > > Bob - W6OPO > > ______________________________________________________________ > 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 -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.872 / Virus Database: 271.1.1/3402 - Release Date: 01/25/11 02:34:00 ______________________________________________________________ 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 Bob - W6OPO
I've found that using the APF with the 400 filter (or wider) dialed-in
provides less ringing than using APF with the 50 filter (DSP) dialed-in. Either way, it's effectiveness is excellent, and that from a twelve-year FT-1000D owner. 73, Kent K9ZTV Jefferson City, MO ______________________________________________________________ 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 Bob - W6OPO
Bob,
I would recommend you review the forum discussions on this subject last year from September thru November. This was discussed extensively. The K3 APF has been optimized. To reduce the sharp high Q audio sound would entail reducing the Q and flattening out the response. In essence reducing its peaking effectiveness. Yaesu had the best APF to date in their early FT1000D's. They modified the APF to broaden the response and lower the Q to please those that didn't like the sound of high Q audio peaking. This rendered the APF almost useless. They later came out with a mod to restore the APF to its original design. The Elecraft K3 APF is a derivative of this fantastic circuit and Elecraft is quite aware of the Yaesu APF history. Here is a response from Elecraft copied from an earlier discussion on this subject that was nearing its conclusion. We will not lower the Q of the existing APF function. We might add > > more Q selections -- someday. But we're not going to rush into further > > changes. Our priority right now is to correct some issues (mostly with > > SSB) and do a new beta release at the end of the week that includes APF. > > > > 73, > > Wayne > > N6KR > > There has been many glowing reports on the APF here in the forum. For me it is absolutely super to use now. It has added a new level to my 160 DXing. I am now able to copy and ambitiously seek new ones on 160 which were down in the noise and unreadable before. 73, Bob K6UJ ______________________________________________________________ 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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