Joe and Richard, I see where the confusion is coming from. I meant to say that one could send the CW id across a whole 15 sec data 'over', NOT alongside each data packet burst. Sorry about the confusion.
The word "PARIS" is considered a standard CW 'word', and consists of 52 dit times, if my numbers are right. The speed limit for automatic ID (according to 97.119(b)(1)) is 20 WPM, so that means the limit is approximately 52 * 20 dit times/minute, or 52 * 5 = 260 dit times in 15 secs. That's just short of 5 'PARIS' words, due to the inter-word gaps. The longest Morse letters are J, Q, and Y - they each have 3 dahs and 1 dit, taking up 13 dit times each. Zero is the longest number with 27 dit times. A call with two digits and 4 letters can be at most 118 dit times long, which leaves plenty of room for a '/' and a suffix. At 20 WPM, as Joe said, that would create a CW id approximately 20 Hz wide. As Joe also said, Part 97.119(a)(4) also seems to indicate that data transmissions can be identified in the 'specifed code' as long as it's published (see 97.309(a)(4)), so there is not real need for the CW id, but it is nice to have since it's offered in the other modes. 97.119 Station identification. (a) Each amateur station, except a space station or telecommand station, must transmit its assigned call sign on its transmitting channel at the end of each communication, and at least every 10 minutes during a communication, for the purpose of clearly making the source of the transmissions from the station known to those receiving the transmissions. No station may transmit unidentified communications or signals, or transmit as the station call sign, any call sign not authorized to the station. (b) The call sign must be transmitted with an emission authorized for the transmitting channel in one of the following ways: (1) By a CW emission. When keyed by an automatic device used only for identification, the speed must not exceed 20 words per minute; ... (4) By an image emission conforming to the applicable transmission standards, either color or monochrome, of §73.682(a) of the FCC Rules when all or part of the communications are transmitted in the same image emission ... 97.309 RTTY and data emission codes. (a) Where authorized by §§97.305(c) and 97.307(f) of the part, an amateur station may transmit a RTTY or data emission using the following specified digital codes: ... (4) An amateur station transmitting a RTTY or data emission using a digital code specified in this paragraph may use any technique whose technical characteristics have been documented publicly, such as CLOVER, G-TOR, or PacTOR, for the purpose of facilitating communications. -- David Tiller Sr. Architect/Lead Consultant | CapTech (804) 304-0638 | dtil...@captechconsulting.com On Jul 5, 2017, at 6:49 PM, Joe Taylor <j...@princeton.edu> wrote: > Hi all, > >> If you knew you had to send an ID with a packet, could you not reduce the >> amplitude of the whole data packet by a db or so and re-allocate that power >> to the CW ID? It certainly doesn't have to be loud, much like repeaters do >> id-under-voice. That way the FT8 signal taken by itself would still be >> constant envelope, and the CW id could be sent way down at FDial+100Hz. If >> the OOK nature of CW is the issue, you could always treat it as FSK using 1 >> Hz and 100Hz. The 1Hz component would get chopped out in the radio, leaving >> the ID and FT8 signal. > > Such a scheme would NOT produce a constant envelope signal. Sending the CW > ID at a frequency offset by 100 Hz, or using FSK for the CW, would make the > signal much wider than an FT8 signal. > >> the classification of the speed of sending morse is weird anyway. >> definition of a word ???? definition of a character ???? > > Morse code speeds are conventionally defined in a very precise way. See, for > example, http://www.kent-engineers.com/codespeed.htm . > > The width of the main spectral lobe of a CW signal in Hz is roughly equal to > the speed in WPM. Fairly strong secondary lobes occur at multiples of this > number. Sending the CW ID at (say) 100 WPM, in order to squeze it into a 15 > s Tx interval, would make the CW ID much wider than an FT8 signal. > > Most likely we will implement CW ID as a separate, dedicated transmission > when the T/R sequence length is less than 30 s. > > NB: Since June 15, 1983 FCC does NOT require US amateurs to use a CWID with > data modes. > > -- 73, Joe, K1JT > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
