APRIL 1998: Thank you for your interest in the MIREX School Day Experiment. There are two initial cautions: 1) Do not transmit APRS packets via MIR until the 27 April authorized test. unless you are a school. Disable your transmitter with the CONTROLS-XMIT command in APRSdos. 2) No matter what software you use, do not try to connect with MIR or anyone else VIA R0MIR. CONNECTIONS are very innefficient in SPACE where everyone can see all packets reliably. If you do not understand the difference between AX.25 CONNECTED protocols and UI frames, then refer to your TNC manual. OBJECTIVE: The objective of the test is to improve the visibility of amateur space communications to students by allowing as many schools as possible to communicate via the packet system on MIR. This message attempts to clarify what you will need for participation. STATION: As a minimum, you will need at least 10 watts or more and an OMNI antenna. You will use normal 2 meter FM and normal AX.25 packet with any TNC. In other words, almost any station will do. SOFTWARE: As a minimum, you won't need any special software. What ever you normally use for packet will be adequate to capture packets from other schools and to send your position/status report. BUT this test does use specialized protocols which will be much more rewarding if displayed by any of the versions of APRS software. SPACE MODE: The unique features of APRS SPACE mode are that it forces APRS to TRANSMIT your position in a very brief format which uses your gridsquare in the UNPROTO TOCALL field in the packet. It also enables your APRS to similarly RECEIVE such packets. If you are not in space mode, you WILL see the position packets from other stations, but NOT their messages, bulletins, or status packets. This is why you also must remember to disable SPACE mode when you return APRS for use on any other frequency. NEVER CONNECT TO ANYONE: No matter what software you use during this experiment, you must understand that all packets will be UNNUMBERED INFORMATION packets using the UNPROTO protocol. DO NOT CONNECT to MIR or any other station. If you do not fully understand the diffrence between CONNECTED packets and UNPROTO packets, please refer to your TNC manual. DUMB TERMINAL SOFTWARE: Even if you are going to use APRS, it will ignore other conventional overhead packets on the downlink . Schools that are interested in logging everything, should consider having a parallel computer/TNC system running if they want to capture and analyse ALL packets in MIR's downlink. In this TNC it will be important to enable MCOM ON so that you can see these normally hidden protocol packets (These are all the CONNECT-REQUEST-BUSY-REJECT packets from the normal users of the MIR BBS). For more information on using just a dumb terminal for the actual test, see the section at the end of this message. As noted you will probablly need two TNC's for this purpose since APRS expects MCOM to be OFF (MCOM ON may work with some TNC formats and APRS, but it is certainly not guaraneed.) TESTING: The easiest test for your system is to tune to any local APRS activity on the national frequency of 144.39 MHz Nationwide. You should quickly receive MANY packets if APRS is in use in your area. Instead of using a path via R0MIR for MIR, enter a path of WIDE or WIDE,WIDE. If you are using SPACE mode in APRS , other stations will ONLY see your POSITION packet, so put some kind of CQ SPACE MODE text in your position text to solicit some one else to test with you. Once there are 2 or more of you using SPACE mode via a local digipeater, then you can operate your space mode APRS to practice for the School Test. READING: In APRSdos, be sure to read the README\SPACE.TXT for back ground or "Ground Station Tracking via Packet Radio", AMSAT Journal page 1, May/June 1993. The latest information about the test will always be posted at: http://web.usna.navy.mil/~bruninga/mirex.html INTERNET LIVE LINK: In addition to the actual radio communications with MIR, stations may consider using the internet in several possible ways as follows: * LIVE display of MIR downlink over Maryland at the page above web.usna.navy.mil/~bruninga/mirex.html using your web browser. * LIVE display of all linked ground stations at www.mirex.net using your web browser. * If you have Mac/WinAPRS or APRSa4 or APRSnet.exe then telnet to the tcpip address of www.aprs.net and your copy of APRS will display everyone connected to the site PLUS all of what they hear. This is a realtime display of everything going on in APRS all over the country live. You may keyboard with any other such TCPIP station live via the internet. * Using the same APRS versions, you can also TCPIP to www.aprs.net port 10001 which will tie you into a separate special net of only the other MIR ground stations so you can practice with them using APRS. This will become much more active as we approach the date of the test. RECOMMENDATIONS: If you will be operating a live internet link to the linked ground station page during the test so that your station feeds all packets you hear to everyone else, you will need to pay special attention to distinguishing between packets you hear via MIR and those you hear via TCPIP and the internet. Check the details of your software to be sure you understand how you are going to do it. You might also want to set up dual computers not only as a backup but to be sure you keep the two packet sources separate. In this case you can connect the receive side of the TNC to the RXD of both computers serial ports so that they BOTH see the MIR packets. But only connect the TXD from the stand-alone PC which will transmit. The RXD needs to go to the internet PC so that your PC will autmoatically feed all MIR packets it hears to all other stations on the internet. This lets schools without amateur radio participate and also schools out of the satellite footprint see what your station is seeing. de WB4APR