SB NEWS @ AMSAT $SPC1225 * SpaceNews 25-Dec-95 * BID: $SPC1225 ========= SpaceNews ========= MONDAY DECEMBER 25, 1995 SpaceNews originates at KD2BD in Wall Township, New Jersey, USA. It is published every week and is made available for unlimited free distribution. * MIR NEWS * ============ A Russian Progress M-30 cargo ship, carrying supplies for the Mir space station, blasted off from the Baikonur cosmodrome in Kazakhstan at 5:31 PM Moscow time (9:31 AM EST / 1431 UTC) on December 18th. The craft delivered 2.3 tons of supplies to the station's crew including fuel, food, scientific equipment and family letters and packages. The unmanned automatic supply ship docked with Mir on December 20th. Three cosmonauts, Russians Yuri Gidzenko and Sergei Avdeyev and Thomas Reiter from Germany, have been in space since September 3rd. Their stay in space is due to last 135 days. The Mir orbital complex has been in orbit since 1986. [Info via Keith Stein] * DOPPLER SHIFT REVISTED * ========================== The following is a follow up to John's good article on Mir and the problems with Doppler shift. Many of us have transceivers that are "channelized" (tuned in discrete steps of several kilohertz each). This means you cannot make any fine tuning adjustments to your receiver or transmitter frequency. Most Mobile/HT transceivers are limited to the smallest frequency change of 5 kHz or 2.5 kHz channel steps. Doppler shift will cause the Mir transmit frequency (145.550 MHz) to appear as if it is 3.5 kHz higher in frequency. If you tune to 145.555 MHz, you may improve you reception (for a 5 kHz rig). Consult your transceiver's operating manual for information on establishing "odd-splits" and program in the following consecutive frequencies into your transceiver's memories: For transceivers with 5 kHz steps: Channel 1 145.550.0 TX 145.555.0 RX Channel 2 145.550.0 TX 145.550.0 RX (simplex) Channel 3 145.550.0 TX 145.545.0 RX For transceivers with 2.5 kHz steps: Channel 1 145.547.5 TX 145.552.5 RX Channel 2 145.550.0 TX 145.550.0 RX (simplex) Channel 3 145.552.5 TX 145.547.5 RX When Mir is approaching your QTH, use channel #1. Then when Mir is over head, use channel #2. When Mir passes your QTH use channel #3. For best results, use a satellite tracking program that displays Doppler shift in real-time. InstaTrack, available from AMSAT-NA, is one such program. This information will assist you in determining when it is best to change memory channels. As you may have noticed, I do not recommend adjusting you uplink frequency for the 5 kHz transceivers. This is because you may have better results if you leave your receiver tuned to 145.550 MHz. The Doppler shift is only at the +3.5 kHz setting for a short period of time at AOS prior to an overhead pass. Shortly after AOS, the downlink signal will drift lower, and in five minutes or less when the spacecraft is overhead, the Doppler shift will be zero for a brief period of time. The downlink signal will then drift lower, down to -3.5 kHz over the next five minutes. The receiver on Mir can work ground stations when the ground station is off frequency by as much as 3 kHz. This is because the receiver on Mir has a relatively wide passband. In some situations, a wide receiver is good, and we are lucky to have such a receiver on Mir. If the receiver on Mir had better selectivity, it would actually make it harder for ground stations with channelized transceivers to access Mir. The following are specifications for the transceiver on Mir along with a few others for comparison: Selectivity at Rig -6dB -60dB =============================================================== ICOM 228 15kHz 30kHz Existing equipment on Mir Yaesu 736R 12kHz 25kHz Typical Base station Yaesu 2400 12kHz 30kHz Typical Mobile transceiver What makes the Mir transceiver work so well is the wide -6dB @ 15kHz receiver passband. This helps the receiver copy signals that are off frequency by as much as 3 kHz. The bad thing, however, is that Mir requires a wide, clear channel. The normal channel spacing required for 2-meter FM is 20 kHz, but because of the Doppler shift, the Mir station requires 25 kHz channel spacing. This means that during a Mir pass, courteous stations should not run other modes between 145.525 MHz and 145.575 MHz to avoid interference with communications taking place with Mir. Remember, only 1 station can connect to the R0MIR-1 PMS at a time. ALL others must wait. [Info via G. Miles Mann, WF1F] * EQUIPMENT REQUEST * ===================== G. Miles Mann, WF1F, is looking for a manufacturer willing to donate a new set of 2-meter monoband transceivers. One transceiver will be sent to the Mir space station and will be used for voice and 1200 baud packet communications. There is also a need for specific modifications to be made to the transceivers. If interested, please contact WF1F (mann@pictel.com). * VK7ZO OSCAR REPORT * ====================== PACSAT AO-16: Normal BBS. DOVE DO-17: Software crash occurred several weeks ago. DOVE is on S-band transmitting MBL data. It will be some time before the satellite is back on 2-meters. WEBER WO-18: 16-Dec-95 *Collecting and Sending WOD Week4: Temps/Impact Ch# 14 2F 30 35 3B 40 *10/14 Papua New Guinea, Coral Sea *11/15 N. Uganda *Monday, New Spectrum 73, IK3WVJ & KB7KCL LUSAT LO-19: November 2. AX.25 downlink on 437.125 mhz. CW experiment is off. Telemetry from northern hemisphere is welcome. LU8DYF. [Normal BBS operating] ITAMSAT IO-26: Nothing heard on either downlink frequencies. WX sats APT 137 MHz only: NOAA 12, 14, Meteor 3/5: Operational. [Info via VK7ZO] * HAPPY HOLIDAYS! * =================== I would like to extend my sincere wishes to everyone for a happy and joyous holiday season, and a healthy, prosperous, and peaceful New Year throughout the world and beyond! Thanks to all who sent holiday greetings over the past week! 73, de John, KD2BD * FEEDBACK/INPUT WELCOMED * =========================== Comments and input for SpaceNews should be directed to the editor (John, KD2BD) via any of the paths listed below: FAX : 1-908-747-7107 FTP : pilot.njin.net cd to /pub/SpaceNews WWW : http://www.njin.net/~magliaco/ PACKET : KD2BD @ KS4HR.NJ.USA.NA INTERNET : kd2bd@amsat.org, magliaco@pilot.njin.net SATELLITE : AMSAT-OSCAR-16, LUSAT-OSCAR-19 MAIL : John A. Magliacane, KD2BD Department of Engineering and Technology Advanced Technology Center Brookdale Community College Lincroft, New Jersey 07738 U.S.A. <<=- SpaceNews: The first amateur newsletter read in space! -=>> /EX