[Elecraft] RTTY Problems

[Don Wilhelm]

Ken,

MMTTY allows you to select 915 for the mark frequency.  If your K2 RTTY 
filters are centered at 1000 Hz, that is a better choice than 1275 Hz.
Those you transmit to will not know the difference, and you can 
communicate with anyone using the same shift (170 Hz).  The software 
compensates automatically.

73,
Don W3FPR

Ken Alexander wrote:
> I'm all for anything that keeps me from fiddling with
> the K2's filter setup!  The thought of playing with
> them makes me squeamish.
> 
> I just downloaded MMTTY and installed it on my
> computer at the office and now see where I can change
> the mark freq to 1275 Hz.
> 
> I know I should be embarassed for asking this, but: 
> If I'm generating tones at 1275 and 170 Hz shift and
> somebody who's software is set up for 2125 & 170 Hz
> tunes me in, he'll centre me in his display and decode
> me fine.  But if he transmits with his setup won't I
> have to re-tune to decode him properly?  
> 
> Ohhh...I know I'm going to regret this, but it's
> Monday and I'm not firing on all cylinders yet!
> 
> 73,
> 
> Ken Alexander, VE3HLS
> 
> 
> --- Don Wilhelm <w3fpr at earthlink.net> wrote:
> 
>> Dohn,
>>
>> You can always tune the PSK31 signal with the K2 VFO
>> so the audio will 
>> appear near 2210 Hz rather than the more traditional
>> 1000 Hz.  But many 
>> RTTY software packages offer another alternative -
>> adjust the RTTY tones 
>> in the RTTY software.
>>
>> I believe the better way is to tell the RTTY
>> software to use lower tones 
>>   rather than the traditional 2210 Hz center.  Of
>> course that cannot be 
>> done if one is using a hardware TU which does not
>> implement a switch for 
>> low tones.  The traditional "Low Tones" for RTTY is
>> 1275 mark and 1445 
>> space - only the shift amount is critical.  If you
>> have your PSK31 
>> filters set for 1000 Hz center and you can tell the
>> RTTY software to use 
>>   915 Hz mark and 1085 space tones both RTTY and
>> PSK31 signals can be 
>> received with the narrow RTTY filters at a 1000 Hz
>> center.
> 
>