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
>>>>
>>>>
>>>>
>>>>
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>>>>
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>>>
>>>
>>>
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