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: <[email protected]>
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: <[email protected]>
> > 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://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
> >
> >
> >
>
>
>
>
> 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
>
