Re: [digitalradio] narrow filters/PSK
-Ursprüngliche Nachricht- Von: digitalradio@yahoogroups.com Gesendet: 07.03.07 22:30:55 An: digitalradio@yahoogroups.com Betreff: Re: [digitalradio] narrow filters/PSK Thanks, Rein, for confirming what I suspected. For a fixed frequency/mode such as pskmail, I'd have to agree completely, but for general use, such as me running PSK31 for one QSO, maybe RTTY for another, and Olivia for yet another, I think the 500 Hz would probably be my best option. That's why I have both 300 and 500 Hz in th FT857D :) Rein Tnx es 73 Dave KB3MOW -- http://pa0r.blogspirit.com Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/themixwgroup http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/wnyar http://groups.yahoo.com/group/Omnibus97 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) * To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[digitalradio] narrow filters/PSK
Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time, they just aren't effective on both. Any input appreciated! Thanks in advance es 73 Dave KB3MOW
Re: [digitalradio] narrow filters/PSK
Thanks, Rick. The 500 Hz makes sense, since some of the modes are over 250 Hz. I have the twin passband, too, but it's just not as effective as I'd like. The APF/ANF on the non-Pro works great on CW, and with just the APF on narrow, I can narrow the passband down to around 30 Hz, but that doesn't do me much good for PSK hi hi! I should have waited for the Pro to come out! Tnx es 73 Dave KB3MOW Hi Dave, Yes, the narrower filters will help a great deal. I have an ICOM rig that needs to be centered on 1500 Hz when operating in SSB modes so I try and move them to that point if I can. Then I have DSP filters that enable me to close the window as tight as I need to. I also have Twin PBT which enables me to dial each side of the interference. But the actual bandpass filters are much more effective with the really strong signals. If I could only have one additional filter than the stock SSB filter, I would go for the 500 Hz filter since it is very useful for CW use as well as narrow to medium digital modes. I have a 270 Hz crystal filter in my Kenwood TS-440SAT that I find rather narrow although some might prefer that for CW. If you go narrower than 500 Hz, you can not use a number of digital modes that are around or slightly under 500 Hz, but may not fit well into at 250 Hz bandpass. 73, Rick, KV9U Dave wrote: Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time, they just aren't effective on both. Any input appreciated! Thanks in advance es 73 Dave KB3MOW
Re: [digitalradio] narrow filters/PSK
We generally use 300 Hz filters for PSK125 and they are too wide. There is no substitute for good narrow Xtal filters. I don't understand how you can try to work PSK31 (50 Hz bandwidth) with a 2.7 kHz filter. That is against all logic (and math). We recommand using the narrowest filters you can get for pskmail. That is the only way to fight Pactor QRM. It helps to use the passband shift and use the sweet spot of the rig at 1500 Hz (we use an Icom 756). Our PI4TUE server has good performance with that, provided you get the filter as narrow as possible (this is for PSK125, which is 4x the bandwidth of PSK31...). A 250 Hz Xtal filter is wide enough for PSK125. 73, Rein EA/PA0R/P -Ursprüngliche Nachricht- Von: digitalradio@yahoogroups.com Gesendet: 07.03.07 19:53:26 An: digitalradio@yahoogroups.com Betreff: [digitalradio] narrow filters/PSK Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time, they just aren't effective on both. Any input appreciated! Thanks in advance es 73 Dave KB3MOW Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/themixwgroup http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/wnyar http://groups.yahoo.com/group/Omnibus97 Yahoo! Groups Links -- http://pa0r.blogspirit.com Yahoo! Groups Sponsor ~-- Something is new at Yahoo! Groups. Check out the enhanced email design. http://us.click.yahoo.com/kOt0.A/gOaOAA/yQLSAA/ELTolB/TM ~- Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/themixwgroup http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/wnyar http://groups.yahoo.com/group/Omnibus97 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) * To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [digitalradio] narrow filters/PSK
I have a hard time visualizing the need for a narrow filter, for such narrow modes. You can sit, in PSK for instance, slap up against another PSK signal and still copy much weaker signals. Thats the whole purpose of the narrow band digital modes to start with. I use WinWarbler (now) to do my digital transmission in both PSK and RTTY, and when I want to do something like Olivia or MFSK etc. I go to MixW. I particularly like WinWarbler because it has the wide band copy ability in PSK. I.E it will automatically copy (and show all the channels) in a 2 or 3 KC bandwidth - at the same time. Using a narrow filter in there would completely negate that fantistic capability. I have never had to use my narrow filters in order to copy a digital signal, and yes I have played with them to see what difference it made. Todays rigs, with their dsp filtering just seem to bypass any need at all for additional filters for digital operation, though I do see the need for CW filters, and have 250 and 270 cy fliters in my two rigs because I use my ears, and not the computer to detect and read that mode. Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk and RTTY, Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalkK vfor i Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk - Original Message - From: kv9u [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Wednesday, March 07, 2007 2:24 PM Subject: Re: [digitalradio] narrow filters/PSK Hi Dave, Yes, the narrower filters will help a great deal. I have an ICOM rig that needs to be centered on 1500 Hz when operating in SSB modes so I try and move them to that point if I can. Then I have DSP filters that enable me to close the window as tight as I need to. I also have Twin PBT which enables me to dial each side of the interference. But the actual bandpass filters are much more effective with the really strong signals. If I could only have one additional filter than the stock SSB filter, I would go for the 500 Hz filter since it is very useful for CW use as well as narrow to medium digital modes. I have a 270 Hz crystal filter in my Kenwood TS-440SAT that I find rather narrow although some might prefer that for CW. If you go narrower than 500 Hz, you can not use a number of digital modes that are around or slightly under 500 Hz, but may not fit well into at 250 Hz bandpass. 73, Rick, KV9U Dave wrote: Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time, they just aren't effective on both. Any input appreciated! Thanks in advance es 73 Dave KB3MOW Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/themixwgroup http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/wnyar http://groups.yahoo.com/group/Omnibus97 Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.7/713 - Release Date: 3/7/2007 9:24 AM
Re: [digitalradio] narrow filters/PSK
Other strong signals in the passband of the IF will densense the following stages and cause AGC action. If you have no AGC, then you will overdrive the sound card audio stage with the strong signal in an attempt to copy the wreak one. The DSP filter in ICOM rigs is at the IF level and is accomplishing the same effect as an xtal or mechanical filter in some other rig such as an FT-817, because it is before the AGC. 73, Leigh/WA5ZNU On Wed, 7 Mar 2007 12:43 pm, Danny Douglas wrote: I have a hard time visualizing the need for a narrow filter, for such narrow modes. You can sit, in PSK for instance, slap up against another PSK signal and still copy much weaker signals. Thats the whole purpose of the narrow band digital modes to start with. I use WinWarbler (now) to do my digital transmission in both PSK and RTTY, and when I want to do something like Olivia or MFSK etc. I go to MixW. I particularly like WinWarbler because it has the wide band copy ability in PSK. I.E it will automatically copy (and show all the channels) in a 2 or 3 KC bandwidth - at the same time. Using a narrow filter in there would completely negate that fantistic capability. I have never had to use my narrow filters in order to copy a digital signal, and yes I have played with them to see what difference it made. Todays rigs, with their dsp filtering just seem to bypass any need at all for additional filters for digital operation, though I do see the need for CW filters, and have 250 and 270 cy fliters in my two rigs because I use my ears, and not the computer to detect and read that mode. Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk and RTTY, Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalkK vfor i Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk - Original Message - From: kv9u [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Wednesday, March 07, 2007 2:24 PM Subject: Re: [digitalradio] narrow filters/PSK Hi Dave, Yes, the narrower filters will help a great deal. I have an ICOM rig that needs to be centered on 1500 Hz when operating in SSB modes so I try and move them to that point if I can. Then I have DSP filters that enable me to close the window as tight as I need to. I also have Twin PBT which enables me to dial each side of the interference. But the actual bandpass filters are much more effective with the really strong signals. If I could only have one additional filter than the stock SSB filter, I would go for the 500 Hz filter since it is very useful for CW use as well as narrow to medium digital modes. I have a 270 Hz crystal filter in my Kenwood TS-440SAT that I find rather narrow although some might prefer that for CW. If you go narrower than 500 Hz, you can not use a number of digital modes that are around or slightly under 500 Hz, but may not fit well into at 250 Hz bandpass. 73, Rick, KV9U Dave wrote: Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time, they just aren't effective on both. Any input appreciated! Thanks in advance es 73 Dave KB3MOW Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/themixwgroup http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/wnyar http://groups.yahoo.com/group/Omnibus97 Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.7/713 - Release Date: 3/7/2007 9:24 AM Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http
Re: [digitalradio] narrow filters/PSK
Thanks, Rein, for confirming what I suspected. For a fixed frequency/mode such as pskmail, I'd have to agree completely, but for general use, such as me running PSK31 for one QSO, maybe RTTY for another, and Olivia for yet another, I think the 500 Hz would probably be my best option. Tnx es 73 Dave KB3MOW Rein Couperus wrote: We generally use 300 Hz filters for PSK125 and they are too wide. There is no substitute for good narrow Xtal filters. I don't understand how you can try to work PSK31 (50 Hz bandwidth) with a 2.7 kHz filter. That is against all logic (and math). We recommand using the narrowest filters you can get for pskmail. That is the only way to fight Pactor QRM. It helps to use the passband shift and use the sweet spot of the rig at 1500 Hz (we use an Icom 756). Our PI4TUE server has good performance with that, provided you get the filter as narrow as possible (this is for PSK125, which is 4x the bandwidth of PSK31...). A 250 Hz Xtal filter is wide enough for PSK125. 73, Rein EA/PA0R/P -Ursprüngliche Nachricht- Von: digitalradio@yahoogroups.com Gesendet: 07.03.07 19:53:26 An: digitalradio@yahoogroups.com Betreff: [digitalradio] narrow filters/PSK Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time, they just aren't effective on both. Any input appreciated! Thanks in advance es 73 Dave KB3MOW Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/themixwgroup http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/wnyar http://groups.yahoo.com/group/Omnibus97 Yahoo! Groups Links
Re: [digitalradio] narrow filters/PSK
Ok I knew there must be some reason, for all the people yelling for it, but have never suffered that particular problem, and if I did I would be flummuxed, as I use the broadband PSK copy all the time. Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk - Original Message - From: Leigh L Klotz, Jr. [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Wednesday, March 07, 2007 3:50 PM Subject: Re: [digitalradio] narrow filters/PSK Other strong signals in the passband of the IF will densense the following stages and cause AGC action. If you have no AGC, then you will overdrive the sound card audio stage with the strong signal in an attempt to copy the wreak one. The DSP filter in ICOM rigs is at the IF level and is accomplishing the same effect as an xtal or mechanical filter in some other rig such as an FT-817, because it is before the AGC. 73, Leigh/WA5ZNU On Wed, 7 Mar 2007 12:43 pm, Danny Douglas wrote: I have a hard time visualizing the need for a narrow filter, for such narrow modes. You can sit, in PSK for instance, slap up against another PSK signal and still copy much weaker signals. Thats the whole purpose of the narrow band digital modes to start with. I use WinWarbler (now) to do my digital transmission in both PSK and RTTY, and when I want to do something like Olivia or MFSK etc. I go to MixW. I particularly like WinWarbler because it has the wide band copy ability in PSK. I.E it will automatically copy (and show all the channels) in a 2 or 3 KC bandwidth - at the same time. Using a narrow filter in there would completely negate that fantistic capability. I have never had to use my narrow filters in order to copy a digital signal, and yes I have played with them to see what difference it made. Todays rigs, with their dsp filtering just seem to bypass any need at all for additional filters for digital operation, though I do see the need for CW filters, and have 250 and 270 cy fliters in my two rigs because I use my ears, and not the computer to detect and read that mode. Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk and RTTY, Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalkK vfor i Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk - Original Message - From: kv9u [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Wednesday, March 07, 2007 2:24 PM Subject: Re: [digitalradio] narrow filters/PSK Hi Dave, Yes, the narrower filters will help a great deal. I have an ICOM rig that needs to be centered on 1500 Hz when operating in SSB modes so I try and move them to that point if I can. Then I have DSP filters that enable me to close the window as tight as I need to. I also have Twin PBT which enables me to dial each side of the interference. But the actual bandpass filters are much more effective with the really strong signals. If I could only have one additional filter than the stock SSB filter, I would go for the 500 Hz filter since it is very useful for CW use as well as narrow to medium digital modes. I have a 270 Hz crystal filter in my Kenwood TS-440SAT that I find rather narrow although some might prefer that for CW. If you go narrower than 500 Hz, you can not use a number of digital modes that are around or slightly under 500 Hz, but may not fit well into at 250 Hz bandpass. 73, Rick, KV9U Dave wrote: Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals
Re: [digitalradio] narrow filters/PSK
Thanks, Danny, but the key to what you said is Todays rigs, with their dsp filtering My 746 is the non-Pro version, and does not have the DSP filtering at all. In USB mode, the bandwidth is greater than 2.6 Khz. Yes, given two signals of around S-5 that are side by side, I can copy either with no difficulty. If there is a +20 signal at either extreme limit of my bandwidth, the PBT will eliminate it nicely. But given an S-5 signal anywhere near that +20 signal, and the S-5 is obliterated by the stronger of the two. My hope is that a 500 Hz filter, closing the primary bandwidth by a factor of 5, will help eliminate some of this, and the PBT will then be more effective for signals quite close to the one I'm trying to copy. I also use WW for all my PSK operations, and for much the same reason. I love the broadband decode as well! But when I get into a QSO, narrower bandwidth is sometimes desirable, for example, on 20 meters on almost any afternoon hi! Seems that instead of DSP, my only option is filtering. Tnx es 73 Dave KB3MOW Danny Douglas wrote: I have a hard time visualizing the need for a narrow filter, for such narrow modes. You can sit, in PSK for instance, slap up against another PSK signal and still copy much weaker signals. Thats the whole purpose of the narrow band digital modes to start with. I use WinWarbler (now) to do my digital transmission in both PSK and RTTY, and when I want to do something like Olivia or MFSK etc. I go to MixW. I particularly like WinWarbler because it has the wide band copy ability in PSK. I.E it will automatically copy (and show all the channels) in a 2 or 3 KC bandwidth - at the same time. Using a narrow filter in there would completely negate that fantistic capability. I have never had to use my narrow filters in order to copy a digital signal, and yes I have played with them to see what difference it made. Todays rigs, with their dsp filtering just seem to bypass any need at all for additional filters for digital operation, though I do see the need for CW filters, and have 250 and 270 cy fliters in my two rigs because I use my ears, and not the computer to detect and read that mode. Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] mailto:digital_modes%40yahoogroups.com moderator http://groups.yahoo.com/group/DXandTalk http://groups.yahoo.com/group/DXandTalk and RTTY, Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] mailto:digital_modes%40yahoogroups.com moderator http://groups.yahoo.com/group/DXandTalkK http://groups.yahoo.com/group/DXandTalkK vfor i Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] mailto:digital_modes%40yahoogroups.com moderator http://groups.yahoo.com/group/DXandTalk http://groups.yahoo.com/group/DXandTalk - Original Message - From: kv9u [EMAIL PROTECTED] mailto:mrfarm%40mwt.net To: digitalradio@yahoogroups.com mailto:digitalradio%40yahoogroups.com Sent: Wednesday, March 07, 2007 2:24 PM Subject: Re: [digitalradio] narrow filters/PSK Hi Dave, Yes, the narrower filters will help a great deal. I have an ICOM rig that needs to be centered on 1500 Hz when operating in SSB modes so I try and move them to that point if I can. Then I have DSP filters that enable me to close the window as tight as I need to. I also have Twin PBT which enables me to dial each side of the interference. But the actual bandpass filters are much more effective with the really strong signals. If I could only have one additional filter than the stock SSB filter, I would go for the 500 Hz filter since it is very useful for CW use as well as narrow to medium digital modes. I have a 270 Hz crystal filter in my Kenwood TS-440SAT that I find rather narrow although some might prefer that for CW. If you go narrower than 500 Hz, you can not use a number of digital modes that are around or slightly under 500 Hz, but may not fit well into at 250 Hz bandpass. 73, Rick, KV9U Dave wrote: Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time
Re: [digitalradio] narrow filters/PSK
Hi Rick/Dave, When the copy gets tough I use a 350hz (-6db) ICOM FL-232 filter in my ICOM-706mkII for copying Olivia 16tones/500hz. The filter skirts are not sharp so it works ok. I used that setup to copy Juergen DL8LE and Massimo IZ0GKZ recently on those EU/NA tests on 160m. Of course :-) I had some help from linux software (Fldigi) and linux OS (Kubuntu 6.06). 73, Irvine N5UNB kv9u wrote: Hi Dave, Yes, the narrower filters will help a great deal. . If I could only have one additional filter than the stock SSB filter, I would go for the 500 Hz filter since it is very useful for CW use as well as narrow to medium digital modes. I have a 270 Hz crystal filter in my Kenwood TS-440SAT that I find rather narrow although some might prefer that for CW. If you go narrower than 500 Hz, you can not use a number of digital modes that are around or slightly under 500 Hz, but may not fit well into at 250 Hz bandpass 73, Rick, KV9U Dave wrote: Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? . Dave KB3MOW http://groups.yahoo.com/group/digitalradio/message/20136;_ylc=X3oDMTM2ZGs4aTBkBF9TAzk3MzU5NzE0BGdycElkAzE4NzExODMEZ3Jwc3BJZAMxNzA1MDYzMTA4BG1zZ0lkAzIwMTQwBHNlYwNmdHIEc2xrA3Z0cGMEc3RpbWUDMTE3MzI5NTUyOAR0cGNJZAMyMDEzNg-- http://groups.yahoo.com/group/digitalradio/post;_ylc=X3oDMTJxMnJuNTUzBF9TAzk3MzU5NzE0BGdycElkAzE4NzExODMEZ3Jwc3BJZAMxNzA1MDYzMTA4BG1zZ0lkAzIwMTQwBHNlYwNmdHIEc2xrA3JwbHkEc3RpbWUDMTE3MzI5NTUyOA--?act=replymessageNum=20140
Re: [digitalradio] narrow filters/PSK
I agee with Danny and don't quite get what Leigh is saying. Dave's question is an interesting one because with my 3-week old DSP capable rig I, have been experimenting with the issue Dave raised. I have the ability to go down to 50 Hz IF-DSP filtering , but to be honest I find the digital bands to be so sparsely populated that I have not needed to use th filtering tha much. I'm waiting for a big contest to test this further. With regard to what Leigh is saying, I have been anxious to find out if my variable AGC and/or DSP filtering offer any significant improvement over the infamous strong PSK signal 'desenses' other signals in waterfall issue. With my admittedly little playing around, I have not found the AGC settings to make that much difference. I just noticed a strong PSK31 signal way out at the 1700 Hz mark on my waterfall. When he transmits my Multipsk waterfall darkens considerably. Turning a fitter on , in this case 1000Hz, eliminates the strong signal at 1700 and the waterfall at the lower end returns to normal. I still have not figured out how to best center on the remaining waterfall with software commands to center on 1000 or 1500 Hz, since these commands center you to parts of the band that you may have filtered out. Still need to find time to practice more. I guess I need filter out the strong signals, shift the remainder of the waterfall so that it is centered on 1000 Hz an then use align or center macros. Sounds like work though. Dave, I think 500 Hz should be all you need for all but the most unusual situations. On 3/7/07, Danny Douglas [EMAIL PROTECTED] wrote: I have a hard time visualizing the need for a narrow filter, for such narrow modes. You can sit, in PSK for instance, slap up against another PSK signal and still copy much weaker signals. Thats the whole purpose of the narrow band digital modes to start with. I use WinWarbler (now) to do my digital transmission in both PSK and RTTY, and when I want to do something like Olivia or MFSK etc. I go to MixW. I particularly like WinWarbler because it has the wide band copy ability in PSK. I.E it will automatically copy (and show all the channels) in a 2 or 3 KC bandwidth - at the same time. Using a narrow filter in there would completely negate that fantistic capability. I have never had to use my narrow filters in order to copy a digital signal, and yes I have played with them to see what difference it made. Todays rigs, with their dsp filtering just seem to bypass any need at all for additional filters for digital operation, though I do see the need for CW filters, and have 250 and 270 cy fliters in my two rigs because I use my ears, and not the computer to detect and read that mode. Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] digital_modes%40yahoogroups.com moderator http://groups.yahoo.com/group/DXandTalk and RTTY, Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] digital_modes%40yahoogroups.com moderator http://groups.yahoo.com/group/DXandTalkK vfor i Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] digital_modes%40yahoogroups.com moderator http://groups.yahoo.com/group/DXandTalk - Original Message - From: kv9u [EMAIL PROTECTED] mrfarm%40mwt.net To: digitalradio@yahoogroups.com digitalradio%40yahoogroups.com Sent: Wednesday, March 07, 2007 2:24 PM Subject: Re: [digitalradio] narrow filters/PSK Hi Dave, Yes, the narrower filters will help a great deal. I have an ICOM rig that needs to be centered on 1500 Hz when operating in SSB modes so I try and move them to that point if I can. Then I have DSP filters that enable me to close the window as tight as I need to. I also have Twin PBT which enables me to dial each side of the interference. But the actual bandpass filters are much more effective with the really strong signals. If I could only have one additional filter than the stock SSB filter, I would go for the 500 Hz filter since it is very useful for CW use as well as narrow to medium digital modes. I have a 270 Hz crystal filter in my Kenwood TS-440SAT that I find rather narrow although some might prefer that for CW. If you go narrower than 500 Hz, you can not use a number of digital modes that are around or slightly under 500 Hz, but may not fit well into at 250 Hz bandpass. 73, Rick, KV9U Dave wrote: Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC
Re: [digitalradio] narrow filters/PSK
Rein Couperus wrote: We generally use 300 Hz filters for PSK125 and they are too wide. There is no substitute for good narrow Xtal filters. I don't understand how you can try to work PSK31 (50 Hz bandwidth) with a 2.7 kHz filter. That is against all logic (and math). We recommand using the narrowest filters you can get for pskmail. That is the only way to fight Pactor QRM. It helps to use the passband shift and use the sweet spot of the rig at 1500 Hz (we use an Icom 756). Our PI4TUE server has good performance with that, provided you get the filter as narrow as possible (this is for PSK125, which is 4x the bandwidth of PSK31...). A 250 Hz Xtal filter is wide enough for PSK125. 73, Rein EA/PA0R/P Rein, you are right as rain! :-) Most Yaesu rigs have a digital passband center freq of 1000hz, but otherwise everything you say above is right on the money. de Roger W6VZV Yahoo! Groups Sponsor ~-- Check out the new improvements in Yahoo! Groups email. http://us.click.yahoo.com/4It09A/fOaOAA/yQLSAA/ELTolB/TM ~- Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/themixwgroup http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/wnyar http://groups.yahoo.com/group/Omnibus97 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) * To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [digitalradio] narrow filters/PSK
using my TS480SAT with both CW filters, can get really narrow on PSK and still copy. don't know much about the IC746. can you menu select cw filters for ssb(digital) reception on USB? or do they only work in CW? John VE5MU - Original Message - From: Dave To: digitalradio@yahoogroups.com Sent: Wednesday, March 07, 2007 12:42 PM Subject: [digitalradio] narrow filters/PSK Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time, they just aren't effective on both. Any input appreciated! Thanks in advance es 73 Dave KB3MOW -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.7/713 - Release Date: 3/7/2007 9:24 AM
Re: [digitalradio] narrow filters/PSK
The 746 allows you to select any filter for any mode, thank goodness!! 73 Dave KB3MOW John Bradley wrote: using my TS480SAT with both CW filters, can get really narrow on PSK and still copy. don't know much about the IC746. can you menu select cw filters for ssb(digital) reception on USB? or do they only work in CW? John VE5MU - Original Message - *From:* Dave mailto:[EMAIL PROTECTED] *To:* digitalradio@yahoogroups.com mailto:digitalradio@yahoogroups.com *Sent:* Wednesday, March 07, 2007 12:42 PM *Subject:* [digitalradio] narrow filters/PSK Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time, they just aren't effective on both. Any input appreciated! Thanks in advance es 73 Dave KB3MOW No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.7/713 - Release Date: 3/7/2007 9:24 AM No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.7/713 - Release Date: 3/7/2007 9:24 AM
Re: [digitalradio] narrow filters/PSK
Danny Douglas wrote: I have a hard time visualizing the need for a narrow filter, for such narrow modes. You can sit, in PSK for instance, slap up against another PSK signal and still copy much weaker signals. Thats the whole purpose of the narrow band digital modes to start with. I use WinWarbler (now) to do my digital transmission in both PSK and RTTY, and when I want to do something like Olivia or MFSK etc. I go to MixW. I particularly like WinWarbler because it has the wide band copy ability in PSK. I.E it will automatically copy (and show all the channels) in a 2 or 3 KC bandwidth - at the same time. Using a narrow filter in there would completely negate that fantistic capability. I have never had to use my narrow filters in order to copy a digital signal, and yes I have played with them to see what difference it made. Todays rigs, with their dsp filtering just seem to bypass any need at all for additional filters for digital operation, though I do see the need for CW filters, and have 250 and 270 cy fliters in my two rigs because I use my ears, and not the computer to detect and read that mode. Not meaning to be argumentative, but I believe most of the above to be objectively untrue from a technical standpoint. A strong adjacent PSK31 signal inside the passband will desensitize any rig's receiver by activating the AGC such that if you try to receive a weaker adjacent signal, you will be unsuccessful. If you disable the AGC often the stronger signal will simply overload the receiver. IF filtering is essential for preventing this, and countless times filtering has made the difference between good copy and no copy. DSP filters are only helpful if they are in the IF, preventing AGC action by signals outside the passband. Software solutions, such as those in MixW or PSK Deluxe, cannot affect the rig's AGC action and are no substitute for good IF filtering. de Roger, W6VZV
Re: [digitalradio] narrow filters/PSK
[EMAIL PROTECTED] wrote: I don't know all the capabilities of my rig ft-897 and psk31 but the other day I had a what appeared to be a 100 watt plus psk31 station that basically with AGC reduced the signal reaching my computer so much that I couldn't copy almost any station never mind weak stations. Is there a way with the FT-897 to eliminate those real strong signals to focus on weaker ones? Yes, there is a 300hz filter available for the FT897 which is fabulous for use on the digital modes. I have one in mine and it works VFB. The 500hz filter is a decent alternative, but I went with the 300hz filter and have been pleased. de Roger W6VZV
Re: [digitalradio] narrow filters/PSK
I am simply saying that I have not had to use such techniques or filters since I started using PSK. I have worked 133 countries in the mode, using my SSB filters, and have yet to have even a nearby signal block out one of them so badly I couldnt copy it. Maybe its my TS570s, my software, my location, etc. I dont know. All I know is that it works. Using broadband copy, I often see 15 or 20 stations being printed out across the band at any given time. Once in a while, someone doesnt know how to limit his power, or how to turn it down so that he has no ALC showing on his meter, and he sends out so many spurs that the broadband can copy him in a dozen places up and down from his normal signal, but even that main signal isnt so strong it disturbs other signals within just a few cycles of it. True, a narrow filter would filter those out, as well as any other signas between them, and make the broadband copy capability useless. It would also disallow the MixW software to have all three of its copy channels/windows operational as well - it doesnt have true broadband copy, but you can set all three windows to copy anywhere across the sound cards passband. Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalkK Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB all DX 2-6 years each . QSL LOTW-buro- direct As courtesy I upload to eQSL but if you use that - also pls upload to LOTW or hard card. moderator [EMAIL PROTECTED] moderator http://groups.yahoo.com/group/DXandTalk - Original Message - From: Roger J. Buffington [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Wednesday, March 07, 2007 9:03 PM Subject: Re: [digitalradio] narrow filters/PSK Danny Douglas wrote: I have a hard time visualizing the need for a narrow filter, for such narrow modes. You can sit, in PSK for instance, slap up against another PSK signal and still copy much weaker signals. Thats the whole purpose of the narrow band digital modes to start with. I use WinWarbler (now) to do my digital transmission in both PSK and RTTY, and when I want to do something like Olivia or MFSK etc. I go to MixW. I particularly like WinWarbler because it has the wide band copy ability in PSK. I.E it will automatically copy (and show all the channels) in a 2 or 3 KC bandwidth - at the same time. Using a narrow filter in there would completely negate that fantistic capability. I have never had to use my narrow filters in order to copy a digital signal, and yes I have played with them to see what difference it made. Todays rigs, with their dsp filtering just seem to bypass any need at all for additional filters for digital operation, though I do see the need for CW filters, and have 250 and 270 cy fliters in my two rigs because I use my ears, and not the computer to detect and read that mode. Not meaning to be argumentative, but I believe most of the above to be objectively untrue from a technical standpoint. A strong adjacent PSK31 signal inside the passband will desensitize any rig's receiver by activating the AGC such that if you try to receive a weaker adjacent signal, you will be unsuccessful. If you disable the AGC often the stronger signal will simply overload the receiver. IF filtering is essential for preventing this, and countless times filtering has made the difference between good copy and no copy. DSP filters are only helpful if they are in the IF, preventing AGC action by signals outside the passband. Software solutions, such as those in MixW or PSK Deluxe, cannot affect the rig's AGC action and are no substitute for good IF filtering. de Roger, W6VZV Announce your digital presence via our DX Cluster telnet://cluster.dynalias.org Our other groups: http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/themixwgroup http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/wnyar http://groups.yahoo.com/group/Omnibus97 Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.7/713 - Release Date: 3/7/2007 9:24 AM
Re: [digitalradio] narrow filters/PSK
Dave wrote: Has anyone tried using either a 250 Hz or 500 Hz filter for PSK31 reception? My Icom IC-746 (non-Pro) has no filters installed, and is wide as a barn door on USB for PSK31. I wondered if either of these filters would help, or would they be too narrow? The pass-band shift does a fair job of eliminating QRM from one side or the other of the selected frequency, but when there are two very strong signals within 2 Khz on each side at the same time, they just aren't effective on both. Any input appreciated! Thanks in advance es 73 Dave KB3MOW ABSOLUTELY! My FT-1000MP/Mark V has both dual 500hz and dual 250hz filters, and I **always** use them in the course of a digital qso. For PSK31 and Hellscreiber, the 250hz filters are often, no usually, the difference between Q5 copy and no copy. For Olivia (500hz) and MFSK, the 500 hz filters are equally essential. The key is to ensure that you align the passband such that the signal that you are listening to is in the center of the receiver's passband. (You can do this with the ALIGN:(passband center freq) macro in MixW, or the Center command in PSK31). Then kick in the filters, and often you will be astounded at the difference in the quality of the copy. Listening wide open is fine when you are looking for someone to work. But once you establish contact, the filters are essential in our crowded digital mode bands. I cannot tell you how many times I have saved a QSO this way from PacTrash, or just other digital op signals. de Roger W6VZV
Re: [digitalradio] narrow filters/PSK
Like most things, there is a middle path on this. Most of the time I can operate digital modes with a wide setting on my passband. The maximum on my ICOM 756 Pro 2 is 3.6 kHz. If I do get some very strong signals, they can and will desense the rig and the waterfall display will weaken, sometimes unacceptably. Then I either use my passband tuning controls to tighten up the filtering and block out the interfering signal. This PBT is not as good as using the selectable filters. The rig has three selections that you can use as defaults but you can also change any one of them with a few keypresses. I often set up my digital modes for 2.3, 1.0 and 0.5 kHz. I can go down to 50 Hz which is very impressive DSP filtering for CW and even PSK31. But you don't have much leeway in tuning. So most of the time (90%+) I use a wider setting and only tighten it up if I have a problem decoding the station I am working. If I have the station centered on 1500 Hz, I can change the filters or the PBT and know that it is the best fit for the passband. My QTH is very rural and far from any local QRO operators. My main QRM is from my own 6 joule energizers (electric fencers) of which I have two to cover different sides of the farm. Thankfully, my rig's noise blanker is very effective against that kind of noise. I have never been very impressed with DSP noise reduction, although it may help a little bit. 73, Rick, KV9U Roger J. Buffington wrote: A strong adjacent PSK31 signal inside the passband will desensitize any rig's receiver by activating the AGC such that if you try to receive a weaker adjacent signal, you will be unsuccessful. If you disable the AGC often the stronger signal will simply overload the receiver. IF filtering is essential for preventing this, and countless times filtering has made the difference between good copy and no copy. DSP filters are only helpful if they are in the IF, preventing AGC action by signals outside the passband. Software solutions, such as those in MixW or PSK Deluxe, cannot affect the rig's AGC action and are no substitute for good IF filtering.
