[Elecraft] 2.8 kHz filter tilt
Hi again, A little while ago I wrote the message below. I am still searching for ways to compensate for the tilt in my new 2.8kHz crystal filter. One way would be to have a way to set the RX equalizer through a serial command / macro. Is this going to happen soon? Another way would be to have the RX equalizer settings stored by mode so they could be different for USB and LSB. Is this going to happen soon? Am I really asking too much here? I spent money getting the 8 pole 2.8kHz filter hoping it would solve the tonality difference between USB and LSB, but achieved nothing. Recently there was somebody on here wishing that Elecraft would sort these filters weeding out the ones with a bad tilt. Should I order another one hoping to get one with a flatter response? AB2TC - Knut Hello all, I recently replaced the 5-pole 2.7kHz roofing filter in my K3 with the 8-pole 2.8kHz hoping to get rid of the difference in tonality between USB and LSB. But the difference is still there. These two links show the noise spectrum of the receiver in USB and LSB. http://ab2tc.getmyip.com:8000/pictures/usb.png http://ab2tc.getmyip.com:8000/pictures/lsb.png In USB there is a definite upward tilt of the passband and the opposite for LSB. This is quite audible. Is this normal and is there anything I can do about it (other than asking Elecraft to add by mode equalizer)? AB2TC - Knut -- View this message in context: http://elecraft.365791.n2.nabble.com/2-8-kHz-filter-tilt-tp5829094p5829094.html Sent from the [K3] 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
Re: [Elecraft] 2.8 kHz filter tilt
Knut, does that Spectrum Lab software allow you to do time averaging for the plots? If you can average over 500+ samples, it will smooth out the plot and make it more useful and readable. 73, Barry N1EU ab2tc wrote: These two links show the noise spectrum of the receiver in USB and LSB. http://ab2tc.getmyip.com:8000/pictures/usb.png http://ab2tc.getmyip.com:8000/pictures/lsb.png -- View this message in context: http://elecraft.365791.n2.nabble.com/2-8-kHz-filter-tilt-tp5829094p5829146.html Sent from the [K3] 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
Re: [Elecraft] 2.8 kHz filter tilt
I sometimes marvel at the number of different directions Elecraft gets pulled with respect to the K3. I can't imagine two more polar opposite message threads than this one and the recent ones discussing AGC action. I'm not trying to overtly judge the merits of either camp, but one is trying to optimize the rig as an audiophile piece of equipment by eliminating 4db of passband tilt on single strong signals in a conversational setting and the other is trying to optimize its communication capabilities by eliminating IMD mush on multiple low level signals in a contest setting. Hopefully for the sake of Wayne, Eric, Lyle and company schizophrenia is not an acquired disease ... 73, Dave AB7E On 12/12/2010 3:18 PM, ab2tc wrote: Hi again, A little while ago I wrote the message below. I am still searching for ways to compensate for the tilt in my new 2.8kHz crystal filter. One way would be to have a way to set the RX equalizer through a serial command / macro. Is this going to happen soon? Another way would be to have the RX equalizer settings stored by mode so they could be different for USB and LSB. Is this going to happen soon? Am I really asking too much here? I spent money getting the 8 pole 2.8kHz filter hoping it would solve the tonality difference between USB and LSB, but achieved nothing. Recently there was somebody on here wishing that Elecraft would sort these filters weeding out the ones with a bad tilt. Should I order another one hoping to get one with a flatter response? AB2TC - Knut Hello all, I recently replaced the 5-pole 2.7kHz roofing filter in my K3 with the 8-pole 2.8kHz hoping to get rid of the difference in tonality between USB and LSB. But the difference is still there. These two links show the noise spectrum of the receiver in USB and LSB. http://ab2tc.getmyip.com:8000/pictures/usb.png http://ab2tc.getmyip.com:8000/pictures/lsb.png In USB there is a definite upward tilt of the passband and the opposite for LSB. This is quite audible. Is this normal and is there anything I can do about it (other than asking Elecraft to add by mode equalizer)? AB2TC - Knut __ 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
Re: [Elecraft] 2.8 kHz filter tilt
Last time I checked, DSM-IV said it was not known to be contagious. 73, Fred K6DGW - Northern California Contest Club - CU in the 2011 Cal QSO Party 1-2 Oct 2011 - www.cqp.org On 12/12/2010 3:06 PM, David Gilbert wrote: Hopefully for the sake of Wayne, Eric, Lyle and company schizophrenia is not an acquired disease ... __ 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
Re: [Elecraft] 2.8 kHz filter tilt
I think you should save your money. Apparently, they appear to have a lot, if not all, filters that behave this way. Short of having a more symmetrical filter in place the two sidebands aren't ever going to sound the same. I know that theory says we shouldn't be able to hear a difference, but it's quite audible and quite annoying to me. Here's a plot of mine: http://k6mhe.com/n7ws/Elecraft_2_8_Filter.gif Wes N7WS --- On Sun, 12/12/10, ab2tc ab...@arrl.net wrote: From: ab2tc ab...@arrl.net Subject: [Elecraft] 2.8 kHz filter tilt To: elecraft@mailman.qth.net Date: Sunday, December 12, 2010, 3:18 PM Hi again, A little while ago I wrote the message below. I am still searching for ways to compensate for the tilt in my new 2.8kHz crystal filter. One way would be to have a way to set the RX equalizer through a serial command / macro. Is this going to happen soon? Another way would be to have the RX equalizer settings stored by mode so they could be different for USB and LSB. Is this going to happen soon? Am I really asking too much here? I spent money getting the 8 pole 2.8kHz filter hoping it would solve the tonality difference between USB and LSB, but achieved nothing. Recently there was somebody on here wishing that Elecraft would sort these filters weeding out the ones with a bad tilt. Should I order another one hoping to get one with a flatter response? AB2TC - Knut __ 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
