[GreenKeys] Getting RTTY on the air

[John, W9DDD]

Harold,

P9 is an adjustment to equalize the AFSK  tones coming out of the 
TU-170.  See page 10.

John, W9DDD

On 11/10/2020 10:29 PM, Harold Hallikainen wrote:
> Thanks! I just recorded my signal off a websdr and then tried playing it
> back into the TU-170. Didn't work! But receiving ITTY works. I checked the
> transmit tone frequencies yesterday, and they looked good. I noticed that
> they are not equal level, though. I'll look at the receive signal on a
> scope and see if I can determine anything. The TU-170 did not even key the
> loop on my signal.
> 
> Time for debug!
> 
> Harold
> 
> 
>> Hi Harold,
>>
>> I think RTTY has been relegated to below 3600 now...sniff.....
>>
>> I believe there might still a RTTY group (RATTSNET) that meets in the
>> evenings on the left coast here on 3598, LSB.  I quit listening to them
>> when they changed to Olivia, so I dunno if they ever changed back.
>>
>> I'm sure some of the other gurus here on the list can fill you in onÂ
>> your technical queries.
>>
>> Keep us updated!
>>
>> Richard kn7sfz in Orygun
>>
>> On 11/10/2020 6:59 PM, Harold Hallikainen wrote:
>>> I've finished connecting my model 15 to the TU-170 to my radio (
>>> https://w6iwi.org/SEA245/ ). I added an audio transformer and a reed
>>> relay
>>> to the TU-170 to drive the SEA245 tri-state audio bus. For testing, I'm
>>> trying to get the RTTY decoder on a KiwiSDR ( http://rx.linkfanel.net/ )
>>> to decode my signal. So, here are some questions.
>>>
>>> 1. I remember from MANY years ago, that LSMFT, or Low Space Makes Fine
>>> Teletype. That, as I recall, is on RF, and it's reversed on AFSK. So,
>>> the
>>> TU-170 uses 2.125 kHz for mark and shifts up 170 Hz for space. That
>>> indicates that the transceiver should be set for LSB to get the signal
>>> right side up. Is this correct?
>>>
>>> 2. How is the transmit frequency normally specified? I can think of
>>> several ways:
>>>
>>> a - Mark frequency
>>> b - Center frequency (Mark frequency minus 135 Hz)
>>> c - LSB "carrier frequency" (Mark frequency + 2.125 kHz
>>>
>>> Is one of these correct? If so, which one?
>>>
>>> 3. What are common frequencies on the HF bands for RTTY? From many years
>>> ago, I think I remember 3.635 MHz for the mark frequency.
>>>
>>> 4. Anything special in the FSK settings on a KiwiSDR? Should the signal
>>> be
>>> inverted?
>>>
>>> THANKS!
>>>
>>> Harold
>>>
>>>
>>>
>>
>>
> 
>