Satgen51 Pacsat Listening 21 March 90 Several recent enquiries have asked about passive listening/reading of Pacsats. The following reviews this situation. First and foremost - Pacsat Listener means Pacsat Screen Printer. This requires an RFI quiet computer with suitable packet software (Proccom, Packcom etc)and a packet TNC. Attached to a simple 2m antenna and FM Rx you can copy telemetry direct from Dove on 145.825 Mhz ( though presently the Dove onboard computer is playing up). Uosat D at 435.07 Mhz needs a more powerful antenna (10XY) and a pre amp to monitor its occasional 1200 bps packet. But remember Uosat will use 1200 bps AFSK only as an interim measure before it goes to 9600 bps FSK. To receive the other Pacsats - Pacsat 437.025, Lusat 437.15, Weber 437.1 and JAS1-B 435.91 you need a good antenna and pre amp for regular copy, plus a receiver modified for AFC control feeding the G3RUH Fuji modem and a modified TNC. What do you get ? Dove has been sending STATUS reports, TELEMETRY and brief messages. JAS1-B is operating on some but not all days , as a packet bulletin board, and is carrying lots of very useful information. Lusat and Pacsat are presently digipeating and sending short control and status updates. They are expected to go to bulletin board usage in the next week or two. Uosat D is sending the regular Uosat data and is testing 9600 bps FSK as well as briefly sending 1200 bps packet at times Making sense of the downlink. If you copy a bbs , you will see bulletins going to other people. They are sent in short packets , with a bit for station A followed by bits for stations B, C and D before you see the next bit for station A. You can read this jumble if you carefully read only the bits addressed to one particular callsign at a time and ignore intervening traffic marked for other callsigns. Broadcast Bulletins. Amsat realise the system will block if everyone calls for the same bulletin at different times. So they intend to introduce a transmission pattern/protocol which interposes regular "straight through" bulletin broadcasts on important topics, with , the normal individual usage of the BBS. This makes it a lot easier for the listener. Uosat D will eventually follow this same mixed BBS/Broadcast protocol. So the packet satellite listener should be in for a treat, with daily access to all the information he or she needs. You do not need a Tx license to enjoy this high tech banquet. Pacsat has recently increased in power quite noticably, when it is not using S band. S band has been received. It is a PSK signal format. Am still getting poor access on my FT211 up ( FT221 is OK). Using PASSAL to monitor Lusat returns shows the junk my uplink is putting into the sat. Rebuild is underway. 73 de John GM4IHJ@GB7MAC