Hi Rick, You obviously do not use MT-63 to pass book traffic on a daily basis on NVIS paths, fore if you did your opinion would be completely different and if you don't believe me, just ask any MARS member that is using a Sound Card based system these days and they will tell you just how robust MT-63 is for an FEC protocol.
As to MIL-STD-188-110 serial tone modem and associated protocols, being as not only FEC but ARQ is provided and with data rates down to 75bps, it is extremely robust, granted 75bps is rather slow, but it just can not be stopped, 75bps is know as ROBUST mode by the way, there is no PSK carrier frequency and its a psuedo spread spectrum waveform within a 3Khz channel, even in MARS-ALE at 75bps its always 3Khz as you can't diddle with the carrier and symbol rate which don't exist as such at higher data rates. /s/ Steve, N2CKH At 05:51 PM 10/27/2007, you wrote: >Steve, > >If MT-63 is robust relative to MIL-STD-188-110, then the latter may not >be all that robust! I do not find MT-63 to be all that robust, and it is >not as sensitive as other modes since it does not work well into the noise. > >Do you have any real world amateur tests yet on the MIL-STD-188-110 >modems using the PC-ALE software approach? > >I have tested this out on 6 meters and it seems to transmit OK. I don't >have anyone close by with the capability to run the program who can also >operate digital modes. > >Also, have you found anyone who has run this software on HF here in the >U.S. in the voice/image portions of the bands? > >It has been several weeks and I have not received any response back from >ARRL yet on my tentative submission to the FCC for an interpretation of >these regulations. Perhaps some are holding back because they consider >the modes not legal in the voice/image areas? My reading of the rules >says that it should be proper to use this software. > >Do you (or anyone else) have any thoughts as to why these modes are not >being at least tested on HF? > >73, > >Rick, KV9U
