Re: [Elecraft] K3 Filter response
I am not sure where it ends up but if you use the web to write you will see an upload file button and an add link button. http://n2.nabble.com/file/n2191105/Clipboard01.jpg Clipboard01.jpg -- View this message in context: http://n2.nabble.com/K3-Filter-response-tp2191015p2191105.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K3 Filter response
And why not use it. http://n2.nabble.com/file/n2191129/27k1.jpg 27k1.jpg http://n2.nabble.com/file/n2191129/2k72.jpg 2k72.jpg http://n2.nabble.com/file/n2191129/400H1.jpg 400H1.jpg http://n2.nabble.com/file/n2191129/400H2.jpg 400H2.jpg http://n2.nabble.com/file/n2191129/13kH1.jpg 13kH1.jpg http://n2.nabble.com/file/n2191129/13kh2.jpg 13kh2.jpg -- View this message in context: http://n2.nabble.com/K3-Filter-response-tp2191015p2191129.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K3 Filter response
Hello, I wrote this message directly from my e-mail software as i do habitually. As most of the time i use Yahoo groups, i've a link for files, pictures uploading. I know i've some memory problems (66 y/o) but i never used n2.nabble.com. By looking your 2k7 filter plot, i saw that my anomaly (the little peak at the right part) is also present on your plot. For me it's no more a local anomaly and the question is partially closed. 73, Rudolf AD6XY wrote: I am not sure where it ends up but if you use the web to write you will see an upload file button and an add link button. http://n2.nabble.com/file/n2191105/Clipboard01.jpg Clipboard01.jpg ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K3 Filter response
The anomaly is not really an anomaly, it is just the other side of the down conversion oscillator. For a filter to pass an SSB audio signal the passband needs to go down to 300Hz or so. For this to happen the attenuation for 0Hz and image frequencies can't be that far down. That is all it is though it is probably better with the 8 pole filter. It can also be eliminated by raising the centre frequency, at the expense of bass response. Unfortunately I don't think you can do this on transmit, though perhaps you could adjust your filter offset. That would not work with the USB/LSB inversion below/above 8MHz. Currently the filter is centred on 1.5kHz by default. The best place for it but if you narrow it down with DSP it is probably better to raise this to 1.8kHz. I am not sure how the filter shift relates to the DSP filter and the crystal filter, i.e. which is adjusted, probably both. However, I find I always need to reduce the filter centre frequency to maintain intelligibility as I narrow the DSP bandwidth. So to make sense of a signal within 1.8kHz I need a 1kHz centre frequency. That is not what I would expect which makes me wonder what the shift control actually does. Mike -- View this message in context: http://n2.nabble.com/K3-Filter-response-tp2191015p2191674.html Sent from the Elecraft mailing list archive at Nabble.com. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K3 Filter response
Mike, Thank you for the explanation; i understand now that this false anomaly is present with the 2k7 and 2k8 filters. May i abuse of your knowledge to explain to me the following behavior : During receive, the 2k7 and 2k8 filter seem to give a ~ 300 Hz at -10dB frequency; it's ok for my use; during transmit, the same filters seems to give a ~ 500 Hz at - 10dB relative to the 1 kHz attenuation; i've tried to shift the bandpass, but naturally, the high frequency is shifted too. As i work essentially with digimodes, i can accommodate with that; but what is the cause of this difference ? (coupling capacitor, etc). I've tried to play with EQUALIZER, but the ALC bars begin to get non desired values... 73 QRO fr Rudolf, HB9ARI AD6XY wrote: The anomaly is not really an anomaly, it is just the other side of the down conversion oscillator. For a filter to pass an SSB audio signal the passband needs to go down to 300Hz or so. For this to happen the attenuation for 0Hz and image frequencies can't be that far down. That is all it is though it is probably better with the 8 pole filter. It can also be eliminated by raising the centre frequency, at the expense of bass response. Unfortunately I don't think you can do this on transmit, though perhaps you could adjust your filter offset. That would not work with the USB/LSB inversion below/above 8MHz. Currently the filter is centred on 1.5kHz by default. The best place for it but if you narrow it down with DSP it is probably better to raise this to 1.8kHz. I am not sure how the filter shift relates to the DSP filter and the crystal filter, i.e. which is adjusted, probably both. However, I find I always need to reduce the filter centre frequency to maintain intelligibility as I narrow the DSP bandwidth. So to make sense of a signal within 1.8kHz I need a 1kHz centre frequency. That is not what I would expect which makes me wonder what the shift control actually does. Mike ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
