Xref: news.cs.tut.fi rec.radio.amateur.space:505 sci.space.news:5112 rec.radio.info:3038 Path: news.cs.tut.fi!news.funet.fi!sunic!EU.net!howland.reston.ans.net!math.ohio-state.edu!news.cyberstore.ca!nntp.cs.ubc.ca!unixg.ubc.ca!kakwa.ucs.ualberta.ca!ersys!adec23!ve6mgs!usenet From: John Magliacane Newsgroups: rec.radio.amateur.space,sci.space.news,rec.radio.info Subject: * SpaceNews 29-Nov-93 * Message-ID: <$spc1129.1993@ampr.org> Date: Mon, 29 Nov 1993 09:49:46 MST Followup-To: rec.radio.amateur.space,sci.space Lines: 212 Approved: rec-radio-info@ve6mgs.ampr.ab.ca SB NEWS @ AMSAT $SPC1129 * SpaceNews 29-Nov-93 * BID: $SPC1129 ========= SpaceNews ========= MONDAY NOVEMBER 29, 1993 SpaceNews originates at KD2BD in Wall Township, New Jersey, USA. It is published every week and is made available for unlimited distribution. * KITSAT-OSCAR-25 NEWS * ======================== KO-25 Operation Status Report 13 (24-Nov-93) 1. General Kernal and other OBC186 S/Ws are all loaded and running well. Spacecraft is showing healthy condition. Battery is being discharged very small amount compared to KO-23. Still using TX0 as it is showing very good performance. 2. Experiments Carried Out 2.1 CCD Earth Imaging System Two camaras onboard are showing good pictures of Earth. The Black and white high resolution (200 meter) camera is showing excellent pictures. The color camera with low resolution (2 kilometer) is also showing great images after some color mapping process. Other than the color imager's gain control difficulty, the camera system is working well and taking pictures everyday. 2.2 InfraRed Sensor Experiment (IREX) IREX has been on since the beginning of the KO-25 operation. This experiment is to acquire I/V characteristics of IR sensors. Passive cooling structure was devised for this experiment and currently we are monitoring the temperature of this cooling system. 3. Experiments on the way 3.1 KASCOM (KAIST Satellite Computer) The initial check out is on the way. A SaTReC developed multitasking kernel and long-term memory test task are to be commenced the initial test. 3.2 DSPE 38.4 kbps Downlink booster is being developed by utilizing DSPE. Protocol test is still being carried out on the ground. 3.3 LEED (Low Energy Electron Detector) After sufficient time for outgassing period, in December this device will be turned on. 4. Other Information The uplink to KO-25 will not be available currently. It will be open with KO-25 BBS service after the system check out completion. Some of the good pictures from KO-25 will be released through KO-23 for the time being. For more info contact: hskim@satrec.kaist.ac.kr FAX) +82 42 861 0064 Tel) +82 42 869 8614 SaTReC, KAIST [Info via Hyung Shin Kim] * MICROSAT ANTENNA POLARIZATION * ================================= There has been a certain amount of confusion concerning the sense of the polarization of the Microsat downlinks. The following by Jim White, WD0E, is an attempt to clarify the situation. The two transmitters in each Microsat are connected to a canted turnstile downlink antenna through a hybrid. The two input ports they are connected to are out of phase with each other. When one transmitter is on, the sense of the downlink will be RHCP, and when the other is on, it will be LHCP. When controllers switch transmitters, they also switch polarization sense. No sense is "normal". During construction there was no attempt to make a particular transmitter a particular sense. The limiting factor was how to fit the semi-rigid cables connecting all the various parts together in the tiny space inside the transmitter module. Additionally, since one of the objectives of the Microsat Project was to create satellites that could be used with very simple portable ground stations using simple omni-directional antennas, there was no need to be concerned about polarization sense. When receiving with a circularly polarized ground station antennas, miss-matched sense can make several dB of difference at times. The most strongly circular signal (or the one with the lowest eccentricity) will be received by the ground station when the bottom of the satellite is pointed directly at it. For stations at about 35 to 50 degrees north or south latitude, this occurres when the satellites are directly overhead and slightly lower in latitude. For all but LO-19, the turnstile is pointed down in the northern hemisphere. For LO-19, it's down in the southern hemisphere. At other times the sense is effected by a variety of other influences and cannot be relied on. If you have a circularly polarized Yagi with switchable sense you can perform a test to see which transmitter provides which polarization. Throughout a pass, but particularly when the satellite is nearly overhead, switch sense every few seconds and see which is stronger. At times you will notice a large difference (AO-16 is 5 S units different on a TS811). The sense that consistantly provides the strongest signal over the majority of the pass is the sense of the downlink for that transmitter. And for all but DOVE, it also correlates to beacon frequency, since the 70 cm transmitters are all on different frequencies. DOVE is a special case since it's two transmitters are on nearly the same frequency. To make the correlations on DOVE you would need to do the same test as above, but also check which transmitter is in use as indicated by the STATUS line. We normally run TX#2 on DOVE because it is more efficient. The following provides beacon frequency and polarization sense for all the Microsat satellites: WO-18: 437.075 PSK LHCP (this TX is bad and not normally used) 437.100 RC RHCP (normally in use) LO-19: 437.153 PSK LHCP 437.125 RC/CW RHCP AO-16: 437.025 PSK LHCP (not presently in use) 437.050 RC RHCP (in use now) DO-17: 145.825 TX#1 LHCP 145.825 TX#2 RHCP (normally used, and in use now) [Info via Jim White, wd0e@amsat.org] * CHINA ON SATELLITES * ======================= The Tsinghua University Amateur Radio Club of Beijing, China is happy to report that the Chinese Radio Sports Association has provided them with some OSCAR satellite ground station equipment that they may use for approximately 6 months in an effort to become active on amateur satellites. The equipment consists of a Yaesu FT-726 dual-band transceiver, a crossed Yagi antenna, a 70cm amplifier, a receive preamplifier, and the elevation/ azimuth rotor system. Walter OE2CAL, an Austrian amateur noted in Europe for his V/UHF activities, and Dieter DJ7BU are scheduled to join the radio club in their efforts ot install the antenna system which has been delayed due to snowy weather. Both men are currently working in Beijing. The students at the Tsinghua University Amateur Radio Club are new to OSCAR operations and are trying very hard to get a station on the air from China. The club is currently in need of satellite reference manuals, books, and satellite tracking software that can help them get on the air. Information pertinent to satellite operation should be directed to Rick Niu, BY1QH, via any of the following paths: Packet: BY1QH @ JA5TX.JPN.AS Internet: Contact gateway_request@arasmith.com for more info Airmail: Rick Niu Public Relations Manager TUARC Room 316 Building 25 Tsinghua University Beijing 100084, China * THANKS! * =========== Thanks to all those who sent messages of appreciation regarding SpaceNews, especially: BY1QH VE1AXJ ZS2LR K7EA OH8UV WD9IYT * FEEDBACK/INPUT WELCOMED * =========================== Mail to SpaceNews should be directed to the editor (John, KD2BD) via any of the following paths: FAX : 1-908-747-7107 PACKET : KD2BD @ N2KZH.NJ.USA.NA INTERNET : kd2bd@ka2qhd.ocpt.ccur.com -or- kd2bd@amsat.org 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 -- John A. Magliacane, KD2BD * /\/\ * Voice : 1-908-224-2948 Advanced Technology Center |/\/\/\| Packet : KD2BD @ N2KZH.NJ.USA.NA Brookdale Community College |\/\/\/| Internet: kd2bd@ka2qhd.ocpt.ccur.com Lincroft, NJ 07738 * \/\/ * Morse : -.- -.. ..--- -... -..