Steve Ellington wrote: > > After filtering the cw signal down to 50hz and you kick in an audio filter > that has 10db or gain, your jaw drops, your eyes glaze over and you > immediately start slobbering about how signals POP OUT OF THE NOISE. >
I've never had an FT-1000D but I know some who do swear by the APF. We had a previous thread about this which resulted in a circuit simulation analysis by Al W6LX. This is using the **EXACT** circuit in the FT-1000D which I found sent to Al. Al's analysis is below (in PowerPoint): http://sites.google.com/site/ft1000apf/w6lxanalysisoftheapfcircuitintheft-1000 You can see the APF has a 6 dB BW of ~50 Hz and ~8.5 dB gain. So how do I emulate that in the K3? I have both the 500 Hz 8-pole and 200 Hz 5-pole filters in my main RX. Normally I set the filter gain to 1 dB for the 500 and 2 dB for the 200, based on Wayne's recommendations. However, you can emulate the APF by setting the gain for the 200 Hz to 8 dB. Now my rig transitions from 1 dB to 8 dB gain as I go to 200 Hz BW or lower, and I have ~7 dB gain over the 500 Hz filter at DSP BW = 50 Hz, which is very close to the FT-1000D APF's characteristics. By pure coincidence I had my rig set to 1822.5 as I was doing this. Lo and behold, at 2:45 PM here I just heard G3FPQ very weak here at 2.5 hours before sunset. Indeed this emulated APF did seem to help, but I'm going to do much more listening before I draw any conclusions. If you have a 200 Hz filter, you might want to give this a try. 73, Bill -- View this message in context: http://n2.nabble.com/K3-honest-question-re-Audio-Peak-Filter-tp4237359p4237738.html Sent from the Elecraft 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
