[RTTY] Receiving RTTY on Sub VFO on FT1000MP?

[Kok Chen]

On Dec 29, 2007, at 6:15 PM, KT0DX wrote:

> I would like to know if there is a way to configure the FT 1000MP  
> (Not a
> Mark V) to be able to receive RTTY on the Sub VFO.  I would like to  
> use
> the Sub VFO to locate the station the DX is working when the DX  
> station
> is operating split.
> ...
>
> Will I need a 2nd sound card to do this?

I think the answer is "it depends on your software."  If there is no  
software limitation, the answer is yes.

In my case, I connect a stereo sound card (in my case a microKEYER  
II) to the stereo output of the FT-1000MP. One single "sound card."

The output from the main receiver output reaches the left stereo  
channel of the sound card and the sub receiver output reaches the  
right stereo channel of the sound card.

cocoaModem's principal RTTY interface has two independent  
demodulators ("receivers"), each has its waterfall display and cross  
ellipse display, which you can see here

http://homepage.mac.com/chen/w7ay/cocoaModem/UsersManual/RTTYPage/ 
WidebandRTTY/WidebandRTTY.html

When active, each "receiver" looks like Fig 12.

Each demodulator's input can choose from either different sound  
cards, or can choose from different stereo channels of the same sound  
card (or even the same channel).  So, I just choose left channel from  
the microKEYER for one "receiver" (demodulator) and the right stereo  
channel from the other "receiver."  (For transmit, I can choose to  
transmit using the tone pair from either the main or sub receivers  
(see the buttons at the bottom left of Fig 11).

When there is a split pileup, one receiver and VFO will usually stay  
put on the DX's QRG.  Or in the case when JA1BK is operating (it  
happened both at Swains and Ducie Islands), I am also watching the  
"main" waterfall since the DX in this case is also moving his  
QRG :-).  The DX moving around also happen during one of the Micro  
Lite DXpeditions (either King George or Thule, I forget which) where  
I believe Trey mentioned his K2 was overheating or something.  So it  
is worth having a frequency agile receiver even on the DX station.

The other VFO is used to tune for the QSX and I can usually see both  
ends of the QSO concurrently most of the time.  It is easy to find  
the QSX (or an empty hole in the pileup where you think the DX will  
be tuning towards) when you are not worried about also watching the DX.

The receive frequency agility (waterfall clicking) is done by  
changing the frequency of the numerical I and Q oscillators and also  
recomputing the receive bandpass filter.  The transmit agility is  
achieved by changing the mark/space tone pair and the transmit  
bandpass filter in real time.  Each time the waterfall is clicked or  
when you use the mouse scroll wheel to fine tune, new receive and  
transmit filters are synthesized on the fly.  Note that this kind of  
frequency agility is only possible using AFSK (yet another of the  
myriad of advantages of using AFSK vs FSK).

73
Chen, W7AY