[Elecraft] K-3: RTTY Dual Passband Question

[RLVZ at aol.com]

Hi Rob,
 
Thank You for your replies to my K-3 RTTY question.  I am  relatively new 
to both RTTY and to the K-3.... so I have alot to  learn! 
 
You mentioned: "Your problem stems from your settings on whatever decoder  
you were using."  I agree that settings need to be correct but  I believe I 
had an issue with the K-3: this being that my  SHIFT control was NOT 
centered.  Would you agree that if the SHIFT  control is not centered then I would 
be off frequency when operating RTTY?   In changing the SHIFT setting I 
notice the received frequency does change.
 
What threw me for a loop was that the first time I switched the  K-3 to 
RTTY Mode the SHIFT control automatically jumped from center to  the left side 
of the display.  I assumed the SHIFT jumping to the Left was  a K-3 default 
and left it there.  With this in mind, does the SHIFT control  always belong 
in the center position when operating RTTY?  If so, then  I wish that would 
be added to the K-3 Manual under RTTY operation  section.

73,
Dick- K9OM
 
 
 
In a message dated 3/3/2010 2:49:57 PM Eastern Standard Time,  
k6rb at baymoon.com writes:

Dick,
Your problem has nothing to do with Dual Passband. Dual  Passband affects
only reception, and just provides two sharp sided filters  on the mark and
space frequencies essentially reducing stuff in  between.

Your problem stems from your settings on whatever decoder you  were using.
If it was MMTTY, for example, your shift should never change  unless you
have AFC or ATC selected. These will try to adapt your signal to  band
conditions and may change your mark frequency or shift.

You  should make sure that you have no options like AFC or ATC selected.

The  other common problem people have is they forget to center their RIT or
XIT  control (if they are "on") so they are now listening or transmitting
offset  from where they are transmitting or listening. If you used RIT to
tune  someone in who was 20 or 30 Hz higher than you, and did not zero it
out,  the next time you tune someone in, you'll be 20 or 30 Hz lower than
they  are. For some filters, that's enough to push you out of the  passband.

Using Dual Passband filtering cuts down QRM from multiple  stations calling
you, assuming some are off frequency. It also makes you  have to tune more
sharply when searching and pouncing. If you use the  regular 400 Hz filter
instead of DP, you'll find it easier to tune, but  you'll also have more
QRM and possibly need to have more repeats. Life is  full of tradeoffs.

Rob K6RB

> Question: If you don't normally  use Dual Passband while in RTTY Mode,
> then
> is it true that you  need to be careful where the "SHIFT"  control is set?
> I am new to  RTTY and in last weekends NA-RTTY Test I  was NOT using Dual
>  Passband, and I was often off-frequency when  changing bands as my  SHIFT
> setting was often different for each  band.  I believe  if I had been 
using
> "Dual
> Passband" that I would  have  been on frequency as that disables the SHIFT
> control.   Question:  if your not using DUAL PASSBAND then what is the
>  proper
> setting for SHIFT?   Perhaps centering the SHIFT in  the middle of the
> K-3's on
> screen display?
> Or is it  true that if NET is On in MMTTY then it will put the  
transmitter
>  on the receiver frequency even if SHIFT is not centered?
>
>  Thanks for your thoughts!
>
> 73,
> Dick-  K9OM
>
>
> Normally I dont need the DPB. But when in RUN-CQ  mode with QRM in the
> last
> NAQP I was very happy to have  it.
>
> 73
> Claude Du  Berger VE2FK
>  _ve2fk at arrl.net_ (mailto:ve2fk at arrl.net)
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