Hi Steve. > I'm setting up a system here to use the 1200 baud pacsats, and am > particularly interested in people's "real world" experience. > > The ARRL manual suggests that "PSK coded signals can be detected and decoded > even when the signal is buried in noise" and also that simple antennae > (J-pole) are the way to go. > > Is this realistic? My G3RUH modem seems to need a signal well above the > noise (by ear anyway) in order to "lock" in - and the pacsat signals are a > lot below that level. I think most people use antennas with gain for Pacsat communications. It's kind of frustrating to have to wait for an additional orbit to complete the download of a file that could have been fully downloaded initially if the downlink antenna only had some gain. :-) As far as noise is concerned, there are PSK packet signals I can copy through noise I can clearly hear, and there are AFSK-FM (DOVE-OSCAR-17 and 2-meter FM variety) packet signals I can't copy through noise I can't hear. The performance difference between the two modulation formats is truly amazing. These observations are based on using a KD2BD Pacsat Modem with a Yaesu FT-726R for PSK communications, and an MFJ-1270B TNC with internal XR2211 based AFSK PLL demodulator for AFSK-FM communications. Incidentially, my modem AFC successfully tracks signals that are *BARELY* audiable through the noise. :-) 73, de John, KD2BD -- -=-=-=-=-=-=-=-=-=-=-=-=- John A. Magliacane, KD2BD -=-=-=-=-=-=-=-=-=-=-=-=- Internet : firstname.lastname@example.org | Voice : +1.732.224.2948 Satellite : AO-16, LO-19, KO-25 | Morse : -.- -.. ..--- -... -.. Packet : KD2BD @ KS4HR.NJ.USA.NA | WWW : http://www.njin.net/~magliaco/ Video : 426.250 MHz/439.250 MHz | FAX : +1.732.224.2060 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Linux: Turns your PC into a workstation. NT: Turns your workstation into a PC.