Tony, You should convert WPM to bauds to apply the formula.
Simpler, and hoping for the best, use a 1500 Hz keyed tone, it allows for symmetric keying sidebands. As in PSK, do not overdrive anything in the TX chain, and you should get a pretty decent signal. With 1200 Hz wide sidebands, you must send quite snappy CW to exceed that. With proper spectrum keying shaping done in the soundcard, a 2.4 kHz wide filter should be enough to send what will be received with another equal bandwidth filter, which is the most common thing for weak signal receiving nowadays. 73, Jose, CO2JA ---- Andrew O'Brien wrote: > " *WHAT IS THE BANDWIDTH OF HIGHER-SPEED HSCW? ISN'T IT MUCH WIDER THAN > STANDARD FILTERS CAN PASS? > > The formula given for the bandwidth of a standard CW signal, Bn=B*K, is > based on make-break ICW, the on-off keying of a carrier, with the leading > and trailing edge of the individual characters shaped by the keying > circuits, the bias of the following stages, etc. Thus the formula is usable > at the lowest HSCW speeds when make-break keying is used. > > But today nearly all HSCW is done by keying an injected audio tone. This > means that if the transmitter is set up properly (i.e., processor off, > nothing overdriven, a proper tone frequency, etc.), the keying is not > shaped > by keying circuit components or adjustments of the transmitter. Rather, the > shape of the rise and fall of the individual characters closely > approximates > the shape of the injected sine wave audio tone. Thus, the above formula > does > not apply for tone-injection HSCW operation. > This is the reason that even the very-high-speed HSCW will fit in the > passband of a standard SSB filter. Of course, misadjusted or overdriven > audio or RF stages may cause spurious signals outside of the intended > range. > But it has proved to be quite easy to generate a good-quality HSCW > signal by > tone injection within the approximate bandwidth of a standard SSB filter." > > On 5/26/07, Tony <[EMAIL PROTECTED]> wrote: >> >> All: >> >> Does anyone know the approximate bandwidth for >> injected audio tone high speed CW? Is there a way >> to calculate this? >> >> Thanks, >> >> Tony KT2Q >> >> >> > __________________________________________ V Conferencia Internacional de Energía Renovable, Ahorro de Energía y Educación Energética. 22 al 25 de mayo de 2007 Palacio de las Convenciones, Ciudad de la Habana, Cuba http://www.cujae.edu.cu/eventos/cier Participe en Universidad 2008. 11 al 15 de febrero del 2008. Palacio de las Convenciones, Ciudad de la Habana, Cuba http://www.universidad2008.cu
