Re: LF: Linear amplifiers , MSK, and 500kHz

[DL4YHF@aol.com]

Hi Alberto,

Will one of the big "pro's" of COFDM -its immunity to multipath and "reflections"- really so important on LF with a very low symbol rate ? - well this is just an initial thought, I don't really know much about COFDM except that it is used in DVB-T (which we don't have in this underdeveloped part of DL yet, hi).

About the peak-to-average ratio (~ crest factor): An analogy to DF6NM's chirped hell (or "fourier SSTV") transmissions came to my mind. To reduce the crest factor, Markus uses a squared phase relationship for all "tones" (alias frequency bins in the IFFT) in a transmitted pixel strip. This is a really large improvement, compared to the classic "concurrent" multi-tone hell (more info available). But I have no clue if a similar principle can be applied to COFDM to reduce the creast factor there (wouldn't be "cOfdm" any longer?) .

Best greetings,

Wolf DL4YHF.