[RTTY] Tinyfsk, 2Tone and USOS

[Charles Lind]

Sending has been done only with 2Tone + Tinyfsk, not MMTTY.  With clone
receive windows, MMTTY gets the "NY NY" wrong unless, as Kok suggests, a
hyphen is placed "599 05-NY NY".  2Tone always receives the message
correctly.  (As an aside, my MMTTY is set up with USOS on transmit checked,
should I want to use MMTTY on transmit----not an option with Tinyfsk).

Chuck, N8CL

On Tue, Sep 29, 2015 at 6:19 PM, Kok Chen <chen at mac.com> wrote:

>
> On Sep 29, 2015, at 11:01 AM, Charles Lind wrote:
>
> > Why is it if I transmit using MMTTY/simple transistor interface I get no
> requests for repeats, and checking with another rig on receive loaded only
> with MMTTY it prints correctly when I send "599 05 NY NY", but when I
> switch to 2Tone/Tinyfsk
>
> Probably because you have set MMTTY to send using "no USOS."  And the
> receiver was also using a non-USOS decoder.
>
> Both TinyFSK and 2Tone (read their code if you don't believe me) forces
> USOS transmissions as default.  As a result, a non-USOS receiver will have
> problems with exchanges sent by TinyFSK and 2Tone that use space characters
> as separators from the FIGS symbol set to the LTRS symbol set.
>
> For people who are not familiar with RTTY, a USOS system will send "599 05
> NY NY" as
>
> <FIGS>599<space><FIGS>05<space>NY<space>NY"
>
> while a non-USOS transmitter sends:
>
> <FIGS>599<space>05<space><LTRS>NY<space>NY"
>
> I'll leave it as an exercise for the reader to decode the two above
> streams on (i) a USOS receiver and (ii) a non-USOS receiver.
>
> 73
> Chen, W7AY
>
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