But never use RX based twin peak filtering with 2Tone. May well sound better to
the human ear but it will be worse for the decoder. 2Tone uses optimised
filtering and anything that narrow in the RX will cause increased Intersymbol
Interference (ISI) resulting in a higher error rate.
My recommendation is to use RX bandwidth no narrower than 350Hz as the steep
slopes considerable group delay distortion. This causes some parts of the
signal to be delayed relative to other parts - it causes the signal to spread
over time and increases ISI. Increased ISI means higher probability of
character errors.
The tone filters in 2Tone are 45.45Hz wide at -6dB and <90Hz at -60dB. Also use
slow AGC as fast AGC can generate artefacts.
73 David G3YYD
-----Original Message-----
From: RTTY [mailto:rtty-bounces@contesting.com] On Behalf Of Jim W7RY
Sent: 27 October 2017 22:02
To: GL-DJ3IW-Web; 'Joe Subich, W4TV'; rtty@contesting.com
Subject: Re: [RTTY] Intel NUC, anyone?
But the twin peak RTTY filter is not available in data mode!
73
Jim W7RY
-----Original Message-----
From: GL-DJ3IW-Web
Sent: Friday, October 27, 2017 10:06 AM
To: 'Joe Subich, W4TV' ; rtty@contesting.com
Subject: Re: [RTTY] Intel NUC, anyone?
Hi,
of the newer ICOM rigs I had the 756-Pro3, IC7700 and now the IC-7851.
All of them allow to set (RX-) filter width down to 50Hz in the USB-(LSB-) Data
modes.
It's all software.... Looking into the manual the same applies for the 7600.
73 de Goetz DJ3IW
> -----Ursprüngliche Nachricht-----
> Von: RTTY [mailto:rtty-bounces@contesting.com] Im Auftrag von Joe
> Subich, W4TV
> Gesendet: Freitag, 27. Oktober 2017 14:44
> An: rtty@contesting.com
> Betreff: Re: [RTTY] Intel NUC, anyone?
>
>
> > I'll have to look at my Kenwood TS-590SG to see if it's the same as
> > the Icom.
> It is not. The new Kenwood (TS-590, TS-990 at least), Yaesu (since
> FT-2000) and Elecraft (K2, K3, K3s, etc.) all permit using narrow
> receive filters in DATA mode receive.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 10/27/2017 9:23 AM, Jim W7RY wrote:
> > No... But it is a HINT for radio and software manufactures....
> >
> >
> > I'll have to look at my Kenwood TS-590SG to see if it's the same as
> > the Icom. It's not interfaced with N1MM. It's on my test bench.
> >
> > 73
> > Jim W7RY
> >
> >
> >
> > -----Original Message----- From: David G3YYD
> > Sent: Friday, October 27, 2017 8:15 AM
> > To: rtty@contesting.com
> > Subject: Re: [RTTY] Intel NUC, anyone?
> >
> > Is that a learning moment that says: Don't buy an ICOM?
> >
> > 73 David G3YYD
> >
> > -----Original Message-----
> > From: RTTY [mailto:rtty-bounces@contesting.com] On Behalf Of Jim
> > W7RY
> > Sent: 27 October 2017 13:13
> > To: rtty@contesting.com; Joe Subich, W4TV
> > Subject: Re: [RTTY] Intel NUC, anyone?
> >
> > Agreed Joe!
> >
> > The Icom IC7300 is like this. I wish radio manufactures would allow
> > AFSK when in RTTY mode with a simple menu change.
> >
> >
> > There are ways to clean up an AFSK signal...
> >
> > But then again.... You're selling interfaces!
> >
> > 73
> > Jim W7RY
> >
> >
> > -----Original Message-----
> > From: Joe Subich, W4TV
> > Sent: Thursday, October 26, 2017 5:59 PM
> > To: rtty@contesting.com
> > Subject: Re: [RTTY] Intel NUC, anyone?
> >
> >
> >> Another is that some rigs have transmit filters that are only
> >> usable in FSK mode
> > Actually, that is receive filters. Nearly all of the older Kenwood,
> Icom
> > and Yaesu rigs limited the narrow filter to "RTTY" (FSK) mode
> only. Icom
> > still limits its "twin peak" filter to RTTY only.
> >
> > While many rigs are not as clean on FSK as they can be on AFSK, FSK
> > is a whole lot cleaner than many AFSK signals (particularly those
> > with
> "Windows
> > noises", hum, clipping products from over driving the mic preamp,
> > RFI due to uncorrected common mode RF on the antenna leads, open
> > ground
> connections,
> > audio from open microphones, etc. With FSK it is easier to generate
> > a "passable" signal for those who either do not care or don't know
> > how to generate a clean AFSK signal.
> >
> > 73,
> >
> > ... Joe, W4TV
> >
> >
> > On 10/26/2017 6:21 PM, iain macdonnell - N6ML wrote:
> >> On Thu, Oct 26, 2017 at 12:56 PM, Peter Laws <plaws0@gmail.com> wrote:
> >>> On Thu, Oct 26, 2017 at 2:14 PM, David G3YYD
> >>> <g3yyd@btinternet.com>
> > wrote:
> >>>
> >>>> from FTDI. But why spend money on a box when you can just use
> >>>> AFSK for a very small sum in making your own sound card to rig lead.
> >>>
> >>>
> >>> Why do some hams use a straight key for CW? A there are any
> >>> number of keyers and interfaces that can produce perfectly timed
> >>> CW using a keyboard for input.
> >>
> >> That's kindof a weak argument. Sending CW with a straight-key is a
> >> skill (some would say an art). There's no special (operating) skill
> >> involved in FSK vs. AFSK.
> >>
> >> The usual argument for FSK is that you don't have to worry about
> >> getting the audio level right, and keeping the audio clean. Another
> >> is that some rigs have transmit filters that are only usable in FSK
> >> mode (IIUC).
> >>
> >> 73,
> >>
> >> ~iain / N6ML
> >> _______________________________________________
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> >>
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