Nino:
I have not had luck with Chip...not a single QSO so far. On 40 meters local NVIS test it did not work. Maybe the 300 baud chip rate was too fast for it to work. Would it be prefarable to use it on a "close to the MUF, single ray link"?? I would like to try it on the air. How has been the actual experience with Chip modes? 73 de Jose, CO2JA ---------- Original Message ---------------------------------- From: "Nino Porcino \(IZ8BLY\)" <[EMAIL PROTECTED]> Reply-To: [email protected] Date: Mon, 22 Jan 2007 18:18:07 +0100 >Walt/K5YFW wrote: > >> if you may be receiving 1, 2 and 3 hop signals. How does this affect BPSK >> and QPSK signals from for example PSK31/63/125? > >the 3 different signals will sum at the receiver, but, having each one a >different phase, the sum is destructive with the result that they tend to >cancel. If the paths are stable you notice a drop in the signal strength but >if paths are unstable (as it is often the case) one signal may win over the >others and the phase of the PSK decoder will wander back and forth. The >clock recovery is also problematic because of the unstability of the >reference. > >Among the possible solutions to multipath there is the spread spectrum >modulation (as in Chip64) where the symbols at the receiver aren't expected >at a precise timing, but are decoded in a "clockless" manner. In Chip64 >signal scope you can actually see the signal trace wandering left and rigth >due to path hopping or see the ghosted trace of the secondary path. > >Nino/IZ8BLY > > > ______________ ______________ ______________ ______________ Correo enviado por ElectroMAIL. Facultad Eléctrica. CUJAE Dominio: electrica.cujae.edu.cu
