[time-nuts] RS 232

Didier Juges shalimr9 at gmail.com
Sat Jul 27 05:05:31 UTC 2013


Most CW operators use "keyers" to generate the dits and dahs precisely. The keyer can be controlled directly by the computer or be a software Meyer or be controlled by an iambic key connected to the computer. A few operators still use straight keys like the J38 or a 'bug' like the Vibroplex. The key is the input method, or the keyboard.

Some software, like the N1MM contest logging software have an embedded software keyer and also support a separate external keyer.

Didier KO4BB

Bob Camp <lists at rtty.us> wrote:
>Hi
>
>….. but why route the key *through* the computer if you are generating
>the side tone off of RF…
>
>Bob
>
>On Jul 26, 2013, at 6:16 PM, Brian Alsop <alsopb at nc.rr.com> wrote:
>
>> Actually computers generate probably 98% of the code during so called
>radio contests.  During a contest weekend it is not at all unusual for
>individuals to make thousands of contacts.  Computers automate the
>drudgery of sending your call thousands of times and most exchanges.
>> 
>> However even during these contests, the manual key has to sometimes
>be used to provide corrections or handle situations not covered by
>"canned" messages.
>> 
>> Because of the tremendous adjacent and even on frequency
>interference, computers have proved incapable of decoding code with the
>accuracy and speed of a human in real time.
>> 
>> Brian
>> 
>> On 7/26/2013 22:04, Bob Camp wrote:
>>> Hi
>>> 
>>> There's also the time honored approach of generating the side tone
>off of the generated RF. In that case the latency to the transmitter
>would matter quite a bit. I have no idea *why* you would run the key
>through a computer in that case ….
>>> 
>>> Bob
>>> 
>>> On Jul 26, 2013, at 4:52 PM, Jim Lux <jimlux at earthlink.net> wrote:
>>> 
>>>> On 7/26/13 12:50 PM, Didier Juges wrote:
>>>>> There is a difference between managing the latency (as in ensuring
>that sound and video are synchronized, but latency itself is
>acceptable) and minimizing the latency as in a Morse code keyer where
>the operator has to manually control the generation of elements that
>can be as narrow as 20mS (one dit at 60 words per minute) while getting
>timely aural feedback. That means you need the sound to start and stop
>within less than about 5 mS following the key closing and opening.
>>>>> 
>>>>> It is trivial to do on a microcontroller running at 1MHz but
>surprisingly harder to do on a 2GHz Windows machine.
>>>>> 
>>>>> It is not just a matter of time stamping the key closure, you have
>to get the sound system starting and stopping.
>>>>> 
>>>> 
>>>> Yep. although, since the propagation path is on the order of 100
>milliseconds, providing feedback to the user directly from the
>interface works quite well (e.g. generating tones directly from the
>keying).
>>>> 
>>>> The challenge is trying generate the sidetone through Windows.  
>But really, there's no reason why you can't have a "keying box" that
>provides the direct side tone and sends the events to the host
>computer.  Then the issue is more about keeping constant latency (or
>else the CW will be really, really hard to copy)
>>>> 
>>>> It's not like an extra 10 milliseconds of delay between keying and
>the emitted RF waveform makes any difference at the other end.
>>>> 
>>>> 
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