[RTTY] INRAD filter question

[David VE3VID]

So its all good news.  Adjusting the IF shift brought the RTTY signal into the passband of the 400hz filter using AFSK in LSB.  Notwithstanding the technical reasons this worked,  it was a beautiful thing to see for someone who had been doing casual RTTY for a year using SSB width filters.  Conditions on 15 & 20m were pretty nice this afternoon and trolling through the RTTY band segment working one station after another...........sweet.  I'm ecstatic.  The 450 is now the dedicated digital rig.

 

I do think that getting my setup to transmit FSK would have some benefit........but Joe,  I'm the guy you want sewing your face back on when you flip your sled over somewhere north of 60.  If you have to wait for me to find a pair of NPN transistors first, well, it might not go so well.............hihihi  :)   Seriously...............do you know of a commercial product.  Dont forget, it took me 7+ months to get the INRAD filters working   :)

David



 


> Date: Sun, 26 Sep 2010 18:07:33 -0400
> From: lists at subich.com
> To: rtty at contesting.com
> Subject: Re: [RTTY] INRAD filter question
> 
> 
> > The TS-450 has a +/-2.2Khz IF shift. This may not be quite enough to
> > get the RTTY signal inside the passband. The 450 also has a menu
> > option to change the receiver tone from 2125 to 1275hz. This may be
> > irrelevant though as it is for FSK mode.
> 
> If the narrow filter is centered at 600 Hz in LSB, a 2.2 KHz offset
> should get you to 2800 Hz which should be more than enough. Check
> it though.
> 
> > PLAN-B if this fails, is there a simple& inexpensive interface
> > that I can use to do true FSK. USB to 13pin DIN...........??
> 
> See the information on AA5AU's web page:
> http://www.aa5au.com/rtty.html.
> You will need a pair of NPN transistors driven from the RTS/DTR
> lines of a typical USB to serial converter with EXTFSK to generate
> the FSK/PTT signal. You can continue to use the Signalink USB for
> PSK31/other digital modes and for receiving RTTY.
> 
> 73,
> 
> ... Joe, W4TV
> 
> On 9/26/2010 11:11 AM, David VE3VID wrote:
> >
> > Confusion is clearing a bit, check my thinking on
> > this.................. The 400hz filters are listening over a
> > portion of the band away from the section where the mark and space
> > tones will be heard. So the reason it sounds so beautifully quiet is
> > because I'm listening to the null outside the filters bandpass.
> > Yes?
> >
> > The TS-450 has a +/-2.2Khz IF shift. This may not be quite enough to
> > get the RTTY signal inside the passband. The 450 also has a menu
> > option to change the receiver tone from 2125 to 1275hz. This may be
> > irrelevant though as it is for FSK mode.
> >
> >
> >
> > I'll be back in the op chair this afternoon and give these options a
> > try then get back to the email thread. PLAN-B if this fails, is
> > there a simple& inexpensive interface that I can use to do true FSK.
> > USB to 13pin DIN...........??
> >
> >
> >
> > David
> >
> >
> 
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