Thanks Joe and Jay,
The common low tones used in Europe was what I meant. Unfortunately, in
in RTTY, 'polarity' is important. Unlike 'mirror modes' (which actually
has some other name that I can not recall) such as Pactor II or PSK-31,
RTTY must remain in sync. Mirror modes (NRIZ - Non return zero?) can be
operated in reverse or not. Hence, their major problem is that of where
to set the tuning dial.
SCS, makers of Pactor - use a low tone setting of 1200Hz/1400Hz which is
defaulted to USB. Luckily most manufacturers of hardware and software
allow the TX and/or RX tones to be reversed. The trick is to keep in
sync and (if your rig does not automatically adjust your dial) know the
offset from Mark Freg (Center Freq, whatever designation you choose).
By convention we use LSMFT, but I've seen plenty of Europeans operate
RTTY in reverse and it works just fine because their contacts all
operate in reverse, too. Sad, but true!
73 de Phil - N8PS
-----
Quoting WS7I <ws7ik7tj@gmail.com>:
> Actually Joe is correct. 1275/1445 for 170 Hz shift. These were
> widely used as IARU standards called for these "low tones".
> Commercial and Military used them for a long time as they weren't as
> concerned about the second Harmonic and spurs.
>
> Note that the high tones were 2125/2295/2550/2975 that covered the
> other shifts that were widely used 425 and 850 Hz as well in years
> gone past. Which also was a problem as the 850 Hz often was outside
> the 300 to 2400 Hz design range. Thus the military went to 2000 Hz
> center 1575/2425 to just fit in the "normal" passband.
>
> Jay WS7I
>
> On Wed, Jun 8, 2011 at 8:31 PM, Joe Subich, W4TV <lists@subich.com> wrote:
>>
>> Actually "low tones" were 1275/1445 ... more common in Europe than
>> in the US. 915/1085 (centered on 1000 Hz) is another artifact of
>> modern programmers who did not understand RTTY and were used to
>> 1 KHz as a "benchmark" in PSK31.
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>>
>>
>> On 6/8/2011 8:59 PM, Jim W7RY wrote:
>>> The use of the name "high tones" refered to 2125/2295. Low tones were
>>> around 900/1070 (give or take).
>>>
>>> Hal communications manufactured ST-6000s with either set of tones.
>>>
>>>
>>> Please don't confuse high/low tones with which one is mark or space. It's
>>> either mark or space. Not high or low tone.
>>>
>>> 73
>>> Jim W7RY
>>>
>>> --------------------------------------------------
>>> From: "Joe Subich, W4TV"<lists@subich.com>
>>> Sent: Wednesday, June 08, 2011 12:22 PM
>>> To: "Phil Sussman"<psussman@pactor.com>; "RTTY"<rtty@contesting.com>
>>> Subject: Re: [RTTY] Mark& Space - High Tones
>>>
>>>>
>>>>> On USB I believe the designations should be reversed, since 2125 Hz
>>>>> would be the LOWER RF frequency.
>>>>
>>>> You are correct. MARK is the tone that provides the *HIGHER* RF
>>>> frequency. Thus if you use USB AFSK the conventional "High tones"
>>>> would be 2295 Hz = Mark and 2125 = Space.
>>>>
>>>> Nearly all material on RTTY (and most Yaesu transceivers designed prior
>>>> to the FT-9000/FT-2000/FT-950) assumes operation in LSB as that was the
>>>> "standard" for nearly 30 years until the "lazy programmers" showed up
>>>> with multi-mode software like HRD, fldigi, MixW, etc. that only worked
>>>> in USB.
>>>>
>>>> Unlike software from the "lazy programmers," MMVARI allows selecting
>>>> *either* USB or LSB for sideband sensitive modes like RTTY, MFSK, and
>>>> QPSK.
>>>>
>>>> 73,
>>>>
>>>> ... Joe, W4TV
>>>>
>>>>
>>>> On 6/8/2011 12:58 PM, Phil Sussman wrote:
>>>>> I've been wandering on the AA5AU RTTY pages in search of
>>>>> Don's email address.
>>>>>
>>>>> After my exchange with Chen, I had a question about the
>>>>> RTTY Intro page on Don's site. It is noted that high tones
>>>>> are 2125Hz and 2295Hz (170 Hz split), Mark and Space
>>>>> respectively. While nothing is specifically mentioned at
>>>>> that point, the Mark and Space designations given are only
>>>>> applicable for LSB. On USB I believe the designations should
>>>>> be reversed, since 2125 Hz would be the LOWER RF frequency.
>>>>>
>>>>> Am I right or merely confused?
>>>>>
>>>>> Thanks ES 73,
>>>>>
>>>>> de Phil - N8PS
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> RTTY mailing list
>>>>> RTTY@contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/rtty
>>>>>
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>>>>
>>>>
>>>>
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