Salut Matt
Alors si on veut tenir une conversation, reston en au CW alors....rien de plus simple en soit....
Si tu désire conversé sur les ondes en digitale, va y avec le PSK31, maintenant tu te retrouveras avec très peu d'adepte sur le 144 et 432 ou du moins tu jaseras souvent avec les mêmes amateurs dans ce mode. (Il y en a pas beaucoup)
"Il le fait par un processus mathématique de comparaison avec des tables contenues dans le logiciel. Seulement ce qui est écrit dans ces tables peut être encodé/décodé."
Faux, Pierre utilise le et tu veras que nous pouvons inscrire et recevoir ce que nous voulons maintenant. Il décode ce qu'il recois, oui les anciennes versions fonctionnait de cette façon...By the way nous sommes à la version 7.....de loin de la version 4...!!
Je ne sait pas à quel point en PSK31 et le météor scatter serait possible en VHF....pas certain qu'il puisse faire le travail...trop lent pour les échanges d'informations numériques. Un météor ça passe vite en titi, fsk441 a temps de donné 26 fois l'information en quelques millisecondes.....donc utilison les logiciels adéquats pour les modes adéquats.
Un ajout au WSJT 7, le WSPR, un mode qui est de plus en plus utilisé en Hf et en EME...
WSPR mode was created in March 2008. The name is pronounced “whisper,” which seems appropriate for a mode designed for extremely weak signals; it is an acronym for “Weak Signal Propagation Reporter,” and has come to be used for both the protocol and a computer program that implements it. The protocol was developed for beacon-like signals originating from QRP transmitters on the LF, MF, and HF bands, but also with an eye toward its possible use for making QSOs with very weak signals. WSPR uses structured messages with a high degree of compression, strong forward error correction, an embedded sync vector for establishing accurate time and frequency offsets between transmitter and receiver, and 4-tone frequency shift keying at 1.46 baud. Transmissions last for slightly less than 2 minutes. Total bandwidth is about 6 Hz, so WSPR signals are about 1/60 the bandwidth of JT65B signals and 1/4 the bandwidth of 20 wpm CW. Dozens of WSPR signals can fit into a few hundred Hz of spectrum, with few collisions. The screen shot on the next page shows the WSPR program in use on a 200-Hz segment of the amateur 30 m band.
The WSPR program transmits during a specified fraction of available 2-minute slots, and receives in the rest; a typical “transmitting percentage” is 25%. Messages consist of callsign, grid locator, and transmitter power in dBm; on the HF bands, most operators have been using power levels of
100 mW to 5 W. As you can see in the screen shot below, WSPR signals can be decoded with signal-to-noise ratios as low as –29 dB in the standard reference bandwidth of 2500 Hz. As in JT65, strong forward error correction guarantees that messages are almost always received exactly as transmitted, or not at all.
EME...
Sensitivity: A sensitivity comparison of WSPR mode and other weak signal communication modes is presented in Table 3. The assumed conditions are additive white Gaussian noise, no fading, and Doppler spreading less than 1 Hz. WSPR will be effective over any propagation path that provides S/N exceeding –29 dB in reference bandwidth 2500 Hz, with Doppler spreading less than about 1 Hz. Such paths should include most LF, MF, and HF paths of interest to amateurs.
(http://www.ve2dsb.com/img/wspr_table.gif)
Although designed primarily for use at LF, MF, and HF, the WSPR mode has also been tested on 144 MHz EME. It works well on that path; however, it has some obvious disadvantages when compared with JT65 for general EME use. Two-minute T/R sequences imply that QSOs take twice as long; moreover, two-minute transmissions at 100% duty cycle put greater thermal stress on high power amplifiers. I do not expect WSPR to be effective (in its present form) at 432 MHz and higher, because of too much Doppler broadening at those frequencies. Another potential mode that retains one-minute T/R sequences and achieves nearly the same performance as WSPR is presently under study.
(Nous vous endormez pas S.V.P, longue un peu cette lecture...)
Voila Matt fait ton choix maintenant, tu est le seul maitre à bord.
Ciao!