SOME MORE SURPRISES

Eli Stern, Israel Amateur Radio Club chairman announced a few weeks ago the availability of a deluxe version of our 50th Anniversary award. For a reasonable additional fee, you may have your award mounted on regular wood or olive wood. An award of this type was presented to DARC chairman Karl Voegele DK9HU by the chairman of the IARC. On the award is included the 50th Israel Anniversary medallion struck by the Israel Government for Coins and Medals Corporation. It will be a real attractive gem in your shack..

ERRATUM

We would like to apologise for giving a wrong call sign to our friend Meir Lang who is at present checking the logs for the 40th anniversary award. It should read of course 4X1OZ.

SCHOOL PROJECTS

The next project planned by the IARC for the near future is the bringing amateur radio to the schools. (It is in fact a project, introduced by some former members of the DARC’s department for training and teaching, who opened a firm called AAT, which specialises electronic projects connected to Amateur Radio in the school curriculum.)

The project proposed by the IARC would start with the weather balloons. The students will build the transmitters and launch these balloons, which would transmit back to earth via Packet Radio the gathered information for evaluation by the students.

It certainly is a good idea and the funds seem to be on hand to start a pilot run. If the idea will catch on in Israel, there might be an opportunity to include student in Jordanian schools as well. The balloons will drift eastwards and will, in all probability, come down over Jordan territory.

So why not join hands with our friendly eastern neighbors in a common project with both countries enjoying the results of envisaged increased activity by teaching youngsters the beautiful hobby of amateur radio.

TECHSAT INFO

The Techsat satellite is now in orbit and successfully transmitting preliminary telemetry back to earth. It has been assigned by AMSAT the OSCAR number GO-32 (Gurwin-Oscar 32 - the 32nd official amateur radio satellite since the amateur satellite programme began three and a half decades ago).

The following is a description of the planning, construction and operating of Techsat-2 (We apologise for some of the terse technical language and style employed here. Nonetheless, it should be understood by those satellite mavens amongst us.): In mid 1990 the IARC was offered to join a group of scientists in the Technion Institute of technology in building Israel's very first amateur radio satellite. Of course the club was exited about the idea and several weeks later a group of radio amateurs Technion scientists were sitting together and working in the design goals.

Many years have gone by, with one unsuccessful launch of the Techsat-1 behind us, and Israeli amateurs are still involved in the project. Many of the design concepts of the Techsat are based on the collective experience gained by radio amateurs ever since the launch of the Oscar-I into space. At present the Techsat’s ground station which was built by radio amateurs is operated by hams. When the station isn’t occupied with Techsat missions it is available for regular Oscar communication. Its callsign is 4X6EM and Email goes to: waler@techunix.technion.ac.il.

The current IARC - Techsat project co-ordinator is Shlomo Menuchin 4X1AS (Email: 4x1as@amsat.org)

Techsat-1 and Techsat-2 were an academic program developed at the Technion - Israel Institute of Technology in Haifa. Its aim was a 50-kg, 3-axis stabilised, Earth-pointing microsat, to be launched piggy-back into a 680 km. high orbit. The satellite has a momentum wheel, a static horizon sensor, three magnetotorquers, and a 3-axis magnetometer, all specially designed with a total power consumption of about 3W. The power consumption for all housekeeping functions is less than 10W (including transmitters, receivers, on-board computer, and power conditioning).

The satellite was designed to be launched with an unknown attitude and without stored momentum. After the launch, the wheel was be accelerated to its nominal momentum, and the body slowly stabilised, using "Coarse Cruise" algorithms that utilise magnetometer data only. At this stage, the accuracy had been expected to be within 5 Degree. Finally, in the "Fine Cruise" phase, a static horizon sensor will provide an accuracy of 0.5 Degree (design goal is 0.1 Degree).

This is an overview of the satellite, its hardware, and the experiments to be carried out in the course of the Techsat-2 mission: On Board Computer, Horizon Sensor, Magnetometer, Magnetotorquer, End Of Acquisition Reconfiguration Unit, Field Programmable Gate Array, Modulator-De-Modulator. Development of microsatellite technology and potential technology for minisats. Construction of a microsat with potential applications for communication. Remote sensing space research. Education of aerospace engineers. Junction of academy and industry in a coherent activity. Rapid and low-cost evaluation of new space equipment. Services for radio amateurs. Main Parameters: Stabilisation: 3-axis stabilised, Earth-pointing. Course: 5 Degree, Fine: 0.1 Degree - 0.5 Degree). Orbit: Circular, Sun-Synchronous is optimal. Any inclination above 40 Degree is possible. Altitude: 680 km. Launch: as a piggyback. Weight: 50 kg. Power: 20 Watts average. 10 Watts of it is for house-keeping, and the rest is free for payloads. Communications: Radio amateurs standards and frequencies. It has one of the smallest 3-axis stabilised platforms and is small enough to be launched as a piggyback. The same concept and hardware fits bigger platforms. Its potential is for communication, remote sensing, and research..

The orientation towards simplicity, low cost and low power consumption led to novel hardware. To be emphasised: On-board computer (1 Watt. Full redundancy). Momentum wheel (2.5 kg, 1 Watt). Horizon sensor (1 kg. , 1 Watt, 0.05 Degree). Magnetometer (220 gr., 0.8 Watt). Academic achievements were in the following areas: Satellite architecture. Attitude control algorithms. Methods of the attitude control system testing. Computer architecture. Educational aspects: Students were and are heavily involved in the program. Management aspects: A coherent effort that combines the academy and 12 Israeli High Tech industries. Program management by the academy. System engineering and integration by the academy. Only 5% error in initially estimated budget. Techsat-1 and 2 attitude control makes use of the classical stabilisation technique by a wheel, which has stored momentum, normal to the orbit plane. The stabilisation strategy is based on: Use of Horizon Sensor, magnetometer, magnetotorquers, and a momentum wheel only. No use of gyros and mechanical damping. Low power consumption requirements led to new control hardware, especially designed for Techsat-1 and -2.