See previous posts on this thread for background.
With N9KO Cal's permission, I'm posting some information which might be of
help to other 570 owners having strange problems getting FSK output. Cal's
now up and running on FSK just fine. I had suggested he just turn menu item
46 to OFF to see if his narrow SSB filter might be blocking the FSK transmit
signal in the IF. Apparently it was.
In any case, glad to have him up and running with MMTTY in "real" FSK!
Very 73 and merry holidays to all.
de Jon, K1US
----- Original Message -----
From: "Jon Harder" <jon@praxisworks.org>
To: "Cal Kutemeier" <ckuter@ix.netcom.com>
Sent: Tuesday, December 24, 2002 7:45 PM
Subject: Re: FSK with 570S and MMTTY
> Cal, glad to hear the good news.
>
> I think the following was very likely the problem: --
>
> Since the 570 IF filter works on both transmit and receive, the 1.8 SSB
> filter was blocking the signals at 2125/2295 from getting through the IF
> chain while transmitting. Like standing on the garden hose and wondering
> why there's no water coming out the end. Changing to low tones would then
> solve it. Or if you didn't, and just turned the SSB filter off, the
signal
> can get through. You know which, or maybe both of these, you did to get
it
> working.
>
> "FSK" in the 570 is first generated as an actual pair of audio tones (
yep,
> AFSK) inside the DSP circuitry, then input via the SSB audio balanced
> modulator chain to create the RF (FSK) which passes through the IF and
> filters to the finals.
>
> By turning the SSB filter OFF during FSK you are allowing the RTTY signal
to
> be processed and amplified properly. On the other hand, if you had a 500
> hz CW/RTTY (YK88C1) filter in the IF, it would be centered properly by
the
> 570 circuitry for both CW and FSK RTTY. You might want to think about
that
> for the future if you really like FSK RTTY. Too bad the 570 doesn't have
> provision to switch between filters. That was one reason I moved on first
> to an 850 with multiple filter options, and now to the 870, which does
> everything with DSP. My faithful 850 had provision for two optional
filters
> in each IF, so I could choose widths as narrow as 270 hz from the front
> panel.
>
> In the last year I owned the 570DG, I put in a YK 88 CN1 (270 hz) filter,
> and it worked just great. The manual implies you can't use anything
> narrower than a 500 hz unit on RTTY, only CW. So, I "fooled" the 570 by
> setting menu # 46 to the 500 hz position, and that allowed me to have the
> benefit of the razor sharp 270 on FSK and CW.
>
> Unless you're planning to post to the RTTY list that your problem is
solved,
> and what you did to get it there, I'd like to put up a short report with
the
> explanation just given as one possibility.
>
> Glad you're up and running for Christmas QSOs!
>
> Very 73,
>
> Jon K1US
>
>
>
>
> ----- Original Message -----
> From: "Cal Kutemeier" <ckuter@ix.netcom.com>
> To: "Jon Harder" <jon@praxisworks.org>
> Sent: Tuesday, December 24, 2002 7:20 PM
> Subject: Re: FSK with 570S and MMTTY
>
>
> > Thanks for your tips. I have had 2 FSK QSOs. Don't know which tip
fixed
> > it, but it is working.
> >
> > 73 N9KO
> >
> >
> >
> >
> >
> > ----- Original Message -----
> > From: Jon Harder <jon@praxisworks.org>
> > To: Cal <ckuter@ix.netcom.com>
> > Sent: Tuesday, December 24, 2002 9:29 AM
> > Subject: FSK with 570S and MMTTY
> >
> >
> > > Cal, I've now reviewed your original post and all you have sent me
> > > privately. While I've recently sold my 570 and moved on to an 870,
> I've
> > > kept a copy of all my settings and the manual, just in case ....I
loved
> > the
> > > 570 a lot for portable ops, and as a second transceiver for SO2R.
> Worked
> > > several large contests and much DX with it on FSK at the full 100
watts.
> > > Played around with its settings until I got things optimized and
> reliable.
> > >
> > > Your ACC2 connection looks fine, and I assume you also bring RX to
your
> > > soundcard by using pin 3, -- though the speaker jack is also fine but
> is
> > > AF-gain control dependent. . (While it wouldn't affect FSK keying I
> found
> > I
> > > needed to be sure that all the shields were connected, that is pins 4,
> 8,
> > > and 12. Otherwise the AF out level was pretty low. )
> > >
> > > The fact that you're hearing the signal with keying on the outboard
> > receiver
> > > shows that your most basic setup is fine. What I suspect is that
> somehow
> > > the signal isn't getting through the IF to the finals as it should.
> > >
> > > That's why I suggested turning OFF the menu 46 filter setting
altogether
> > to
> > > see if you can get the power level up where it ought to be, trying it
on
> > CW
> > > mode first. If you've read what I wrote in the review about problems
> > > arising from "tricking" the 570 into using a narrow 500 Hz filter into
> > > thinking it was a 1.8 Hz SSB filter on AFSK, then getting no CW
output,
> > this
> > > is why I suspect the filter / IF combo may be doing something strange
> even
> > > when on a "real" YK 88 SN1.
> > >
> > > But if your CW output is where it ought to be, then the problem may be
> > > elsewhere. In FSK trials, I assume you have the power control up to
50
> > > watts or so to start with? The 570 has no carrier level control, so
> > turning
> > > up the power control is the only adjustment you have to work with.
> > >
> > > Menu 30 will likely need to be set ON for keying to be right side up,
> > using
> > > the AA5AU circuit. I found this true on my 570 as well as all recent
> > > Kenwoods (850 870, etc.) For now it doesn't matter which way it's set,
> > until
> > > you can get a solid carrier with good power out during FSK operation.
> > >
> > > Now some MMTTY - specific comments -
> > >
> > > V. 1.61 is OK for these tests, but I'd suggest you move up to 1.63
right
> > > away. Between 1.61 and 1.62 there were a number of important changes.
> > 1.63
> > > smooths out a number of bugs and improves operation generally. I
think
> > > you'll lke it a lot once the FSK problems are solved.
> > >
> > > In MMTTY Setup I see your Demod tab has Mark set at 1125 Hz. For high
> > > tones, it should be reset to 2125. For years I've preferred low
tones,
> as
> > > that allows more comfortable copy and a good placement within the
center
> > > range of an SSB filter. Set the 570 menu item 31 to 1275 mark, and
in
> > > MMTTY change the HAM default to 1275. The space tone is then1445.
Much
> > > nicer on the ears.
> > >
> > > On the AFC/ATC tab, would recommend turning AFC off for the present,
as
> > this
> > > may be why your mark tone got so far down away from 2125.
> > >
> > > (On the TX tab, I'd move the slider for digital output down nearer the
> > > bottom, to avoid overdriving if you go back to AFSK. )
> > >
> > > On the Misc tab, glad to see you've got the Sound + TxD (FSK) option
> > > checked, so you can monitor your own sounds via the PC.
> > >
> > > This is about it for the present, until I hear how you make out with
the
> > > filter setting menu 46. And on the radio itself, the Filter button
lets
> > you
> > > select WIDE to start with for receiving. Might be a good idea to do
> that,
> > > and also adjust the IF shift to give you maximum audio at the pitch
you
> > > decide to use, 2125 or 1275 mark.
> > >
> > > Best wishes,
> > >
> > > Jon K1US
> > >
> > >
> > >
> >
> >
>
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