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Filter skirts are much improved...but...

K2CM
K2CM Member ✭✭
edited June 2020 in SmartSDR for Windows
0.15.13 The filter skirts are MUCH improved. I am now able to isolate a single station with the 50hz filter on a crowded band on CW. Great! I am now having an issue with noise causing some ringing with the narrow filters. Has anyone else noticed this?

Comments

  • Greg
    Greg Member ✭✭
    edited September 2013
    I agree and was just about to post the same thing about the skirts. I was a fox in a qrp fox hunt last night and the filters were well improved over the last hunt. Still think they could be better but it was a welcome improvement. 73 Greg AB7R
  • W5UN_Dave
    W5UN_Dave Member ✭✭
    edited February 2019
    Yes much improved, but I would like to see the skirts even sharper, especially the 50 hz filter. A good 25 hz filter with extremely sharp skirts would be much welcomed also. I still await the 5 hz audio peaking filter. Until one digs out noise level signals on the low bands, one will not understand the benefit of this. Elecraft K3 wins this battle for now
  • Ed, K0KC
    Ed, K0KC Member ✭✭
    edited September 2017
    I was on CW for a bit last night and also noticed "ringing" with narrow CW filters.
  • K2CM
    K2CM Member ✭✭
    edited September 2019
    Same here. It's more noticeable with weaker signals.
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    I changed this topic to a Problem topic so we can investigate further. Anyone else hearing this?
  • Al_NN4ZZ
    Al_NN4ZZ Member ✭✭✭
    edited March 2017
    Tim, First, agree that the steeper filters are much better. There is a little ringing on 50 hz CW here also. It would be good if it can be improved but the ringing is much less than my other radios at that width. It sounds more like an artifact of the noise and it may be reduced when the NR is improved. Regards, Al / NN4ZZ
  • Ken - NM9P
    Ken - NM9P Member ✭✭✭
    edited June 2020
    Having never run a filter narrower than 250 Hz (on my TS-850) until getting a Flex-1500 in December and now my new Flex-6500, I was astonished at the sharpness and clarity of the new filters, even all the way down to 24 Hz. I expected a filter that narrow to have a lot more ringing. So I am happy at this point. And if Al is correct and the ringing is a noise artifact that may go away with improved NR and better adjustment of AGC-T, then WOW! Perhaps this just classifies me in the "not so good" CW Op category, but even as is, the new filters far surpass anything I have ever used. As they get better, perhaps my CW ops will too!
  • W5UN_Dave
    W5UN_Dave Member ✭✭
    edited February 2019
    I would expect a little ringing at 50 hz, if physics allows a filter to not ring with very steep skirts, go for it. However, please do not broaden the skirts just to lessen ringing. The 50 hz filter on PowerSDR is an example of a poorly skirted filter. Actually, I have found that I am able to use some ringing to an advantage in hearing very weak signals. I cite the audio peaking filter at 5 hz width on my K3, or my old FT1000D as an example of this.
  • Steve-N5AC
    Steve-N5AC Community Manager admin
    edited February 2017
    Do you have NR on? It probably does not make sense to use NR in a narrow bandwidth like 50Hz. The filters are FIR filters which cannot ring.
  • Ned K1NJ
    Ned K1NJ Member ✭✭
    edited February 2017
    The filters use math instead of hardware to achieve the desired bandwidth. You are hearing narrow band noise around the center frequency. Very cool.

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