SB NEWS @ AMSAT $SPC0401 * SpaceNews 01-Apr-96 * BID: $SPC0401 ========= SpaceNews ========= MONDAY APRIL 1, 1996 SpaceNews originates at KD2BD in Wall Township, New Jersey, USA. It is published every week and is made available for unlimited free distribution. * DOHOP SATELLITE NEWS * ======================== Following in the footsteps of Ray Soifer, W2RS, who accomplished cross satellite radio contacts using OSCAR's 6 and 7 in 1974/5, Pat, G3IOR, and Dave, G4CUO, achieved "DOHOP" success with OSCAR-10 to RS-6 on CW on 07-May-84 at 0711 GMT. After many attempts, they finally made successful contact and also contacted Heinz, DL1CF, using OSCAR-10 and RS-5 on 21-Sep-84 under less-than optimum conditions. The next attempt was to link from OSCAR-13 to OSCAR-12. After weeks of trying John, WA3ETD, called on SSB voice to make the first double hop across the pond. John commented, "Guess we made a little history on this one, Dave". The contact was made using 70-cm USB for an uplink, 2-meters across on LSB, and a downlink on 70-cm USB on 24-Nov-87 at 2136 GMT. Enter the 1990's with RS-10/11 and RS-14. This time with a team of interested satellite hams including Ron, G3CAG, John, G4ZHG, Ian, G0NKA, Ted, G6HMS, and Richard, G7MUB, along with their mentor Pat, G3IOR, planned their cross satellite contacts on the chance that RS-14 would be switched to mode "B". Little did they think that Leo, UA3CR, would take the experiments seriously. Ian made a request for RS-14 to be switched to mode "B" via packet radio and (surprise surprise), a reply was received that read, "Which day would you like, and which transponder"? Leo then put the team in direct contact with Andy, RK3KP, at RS3A via packet radio. The team had six weeks to practice the technique of working through two satellites travelling towards each other at a combined speed of 36,000 km per hour. Compensating for the double reversed Doppler shift as the two satellites passed was part of the challenge. Many hours of practice were spent when Europe had gone to bed, and the QRM was at minimum. Confirmation arrived that Andy would switch RS-14 over to mode "B" on 07-Feb-93 for three orbits before the satellite was out of his range. During the first orbit, orbital predictions and final operating frequencies were finalized with the DOHOP team which had grown to include LZ2JH, DJ2MHJ, DJ0MY, and many SWLs calling in on a DOHOP net on 80-meters. Others were in contact via 2-meter FM. The moment that signals were heard from RS-14 will remain one of the most memorable occasions for the team. The satellite had been switched over, just for a bunch of hams in Sherwood Forest. On the second orbit, all of the members teamed up on the transponder 4 minutes before DOHOP time. With 30 seconds to go, all stations changed from RS-10 (2-meters up) to RS-14 (70-cm up). Window time was 3 minutes, 10 seconds. The first station to appear out of the noise was the newest member, Richard, G7MUB, with a good (5x3) signal followed by the rest of the team. Good signals were copied with very unusual Doppler shift. The time was 0012 GMT. By the third orbit at 2:00 AM local time, the team was ready for the big hop across the pond. Unfortunately, the word that the transponder on RS-14 was switched on had not got across due to problems with the 20-meter link. With a window of only two minutes, the first station heard was F8SH followed by W1NU and K2WER, all on CW along with Ron, G3CAG, and John, G4ZHG. The team considered its experiments a success, and the results were compiled and sent via packet radio to Leo, UA2CR. Unfortunately, the switching had repercussions with DB2OS and AMSAT-DL, and no further switching was made available. Nevertheless, the enterprising team had put a new name into the Amateur world: "DOHOP". RS-14's transponder closure signalled the end of many DOHOP experiments. The DOHOP team members have been working DX stateside on RS-15. To date, the members have 44 states worked with 38 confirmed. On RS-10, 88 countries have been worked with 80 confirmed, and on RS-12, 26 countries have been worked with 12 confirmed. RS-12 has recently been switched to mode "KT" and has excellent downlink signals on 2-meters between 145.910-145.950 MHz. With this change, DOHOP experiments can once again commence. Orbit times for RS-12 to FO-20 double-hop contacts are being calculated. Signals from John, K1FX in Connecticut are very good across the pond via RS-12/FO-20. John is looking into 70-cm equipment to complete his link. The new DOHOP challenge involves taking signals from RS-12 using an uplink on 21.220 MHz using CW or LSB crosslinked on 145.920 MHz, to FO-20 inverted in the transponder for a downlink on 435.880 MHz, plus Doppler shift. That's going from HF to VHF to UHF via two satellites! FO-20's 100 kHz passband is little used. Normally the middle 20 kHz of the passband is where most of the activity on the satellite can be found. This leaves 80 kHz for experiments such as DOHOP. Unfortunately, FO-20 is almost a seasonal satellite, with it's apogee and perigee changing every three months. When it's apogee is in the northern hemisphere, the footprint is very good for North America with W1 to W0 and all VE areas. When it's in the South, the footprint is very small and the Doppler shift is a problem. Over the upcoming weeks, if RS-12 remains in "KT" mode, the DOHOP team will establish a pattern of orbits for both RS-12 and FO-20 which have mutual windows. Providing you can see one of the satellites, you can participate in the experiment. When RS-12 is in range, call "CQ DOHOP de callsign" on 21.220 MHz using CW or LSB voice. You might not hear FO-20, but if the mutual window is good then other stations may. If FO-20 is in range, then listen around 435.880 MHz plus Doppler using USB. The experiment will work if stations practice the art of tracking two satellites. The DOHOP team will publish predictions on packet radio, and would appreciate any feedback from stations interested in the experiment. Replies should be addressed to Ian, G0NKA @ GB7DTX.GBR.EU. Thanks for your help. It is much appreciated by the team. [Info via Dave Rowan, G4CUO with thanks to Ian, G0NKA for the relay.] * 1200 BAUD PACSAT USE * ======================== Last week, Chuck, W9ODI, conducted a seven day use survey of the AMSAT- OSCAR-16 and LUSAT-OSCAR-19 "Pacsat" satellites. These satellites contain digital communication transponders that operate at a data rate of 1200 bits per second. Looking at those who uploaded or downloaded files at least once during the week, Chuck found that there were 125 stations active on the satellites with 40 being in the United States. The countries represented include: 6 Germany 5 Spain 6 France 4 UK 8 Italy 3 Denmark and Finland 17 Argentina 8 Canada 8 Australia 6 New Zealand In addition, Oman, Uraguay, Chile, Panama, Israel, Norway, Costa Rica, Netherlands, South Africa, Mexico, and Paraquay were also noted in the survey. Chuck points out that one of the reasons for the lack of activity on the 1200 bps birds lies in the difficulty in running an automated station with BPSK modulation. Some pacsat modems have been found to establish phase lock when not correctly tuned to the BPSK downlink from the satellite. While the modem may "lock" into the signal and supply proper AFC signals to the downlink receiver, little, if any, data can be demodulated if the downlink receiver is not properly tuned. W9ODI typically downloads 80 to 110 thousand bytes of data on a busy pass, while at other times, particularly during the week, the satellites are unused and practically empty. This is a clear indication that most groundstations are operated manually. [Info via Chuck Parmelee, W9ODI] * ARRL ON AO-16 * ================= The following message was recently posted to the AMSAT-OSCAR-16 satellite: To : ALL From: W1INF Time: 171607UTC Date: 28 Mar 1996 ----------------- Hello: This is W1INF, labortory station of the American Radio Relay League in Newington, Connecticut, USA. Whenever possible, we monitor AO-16 passes over our area that occur between 1500 and 1800 UTC, Monday through Friday. 73 . . . Steve, WB8IMY (operator) * THANKS! * =========== Thanks to all who provided news items and sent messages of appreciation to SpaceNews, especially: VK1NH WP4MWK WB5LMJ * SpaceNews AVAILABILITY * ========================== SpaceNews is available regularly on Usenet in the rec.radio.info, rec.radio.amateur.misc, and sci.space.news newsgroups, and on packet radio BBSs worldwide as well as the AMSAT-OSCAR-16 Pacsat satellite. It can also be retrieved using the File Transfer Protocol (FTP) at pilot.njin.net (128.6.7.38) from the /pub/SpaceNews subdirectory. You may also "finger magliaco@pilot.njin.net" for a copy of the latest issue, or access it via the World Wide Web at the following URL: http://www.cs.indiana.edu/finger/pilot.njin.net/magliaco/w. * FEEDBACK/INPUT WELCOMED * =========================== Comments and input for SpaceNews should be directed to the editor (John, KD2BD) via any of the paths listed below: WWW : http://www.njin.net/~magliaco/ PACKET : KD2BD @ KS4HR.NJ.USA.NA INTERNET : kd2bd@amsat.org, magliaco@email.njin.net SATELLITE : AMSAT-OSCAR-16, LUSAT-OSCAR-19 <<=- SpaceNews: The first amateur newsletter read in space! -=>> /EX