Walt DuBose wrote: > As far as I can tell, there is a very large use of FEC which of > course cuts down on the amount of user data throughput. > Additionally, with 65 tones, I believe that the signal is wider than > 500 Hz. Hi Hi.
Yep!...it was meant for VHF and up... > "1. In earlier versions the vertically-scrolling JT65 waterfall > always displayed the frequency range 500-2500 Hz. The range has now > been optionally expanded and made more flexible. By toggling a > button labeled "BW" at the top of the SpecJT window you can change > the displayed bandwidth to 4 kHz. In addition, you can offset the > displayed region in 100 Hz steps by using buttons labeled "<" and > ">", and you can return the range to its default alignment with a > button labeled "|". > > This new feature provides two significant advantages. If your > receiver provides a bandwidth greater than 2 kHz in USB mode, you can > now display up to 4 kHz instantaneously (and with offsets, a total > range of 5 kHz). The Kenwood TS-2000, for example, provides a 5 kHz > bandwidth. The expanded range will make it easier to find other > stations to work -- e.g. in contests, and at 1296 MHz where Doppler > shifts are relatively large. In addition, extending the displayed > spectrum to frequencies below 500 Hz is useful if you are using WSJT > as a display tool when operating on CW." Also, some of the top guns on EME are using WSJT along with Software Defined Radios, on which, bandwidth is easier to adjust while operating. > Does anyone know the actual transmit bandwidth of J65A? It would > appear to be about 2 KHz wide. A snapshot of the waterfall might be used to document it, at least, roughly. > The bottom line is that Joe Taylor, K1JT, has provided some > interesting code based I suppose in part on KA9Q's work, and perhaps > that of Dr. Clark, which combined with the corporate knowledge of > this group might produce a very robust mode with the possibility of > much higher throughput. However, I believe that a new mode based on > this or similar work will be considerably wider than 500 kHz > bandwidth. Would say 500 Hz...which I think is quite consistent with Shannon's statements.... > > 73, > > Walt/K5YFW 73, Jose, CO2JA __________________________________________ 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
