© Electronic Systems Laboratory 1999
by Buchan Milne
WWW:sunsat.ee.sun.ac.za
Sunsat is scheduled to operate its Mode B transponder over South Africa and the USA on Sunday 11 July. We have been operating the SA Sunday passes for 4 weeks now, and this is the second week for the USA. Thanks for all the feedback!
Our power budget allows us to operate the mode B transponder about 60 minutes per week. Hans, ZS5AKV, has been on the SUNSAT Advisory Board since its inception, and will be determining how the transponder will be scheduled in future.
It is likely that we will support South African passes on Sundays, The USA passes can be on other days. Hans reports on this in his bulletin sent to amsat-bb@amsat.org. He asks for feedback/comment/operational reports to be sent to sarlnews@intekom.co.za
Since we still have much commissioning to do on SUNSAT, we will have computer crashes, finger trouble etc in operating the transponder. You shouldn't expect the probability of the repeater being functional on any advertised pass to be more than 75% at present.
South Africa
13:00 to
13:15 SA Time
14:40 to 14:52 SA
Time
USA
18:00 to 18:18 UTC
19:40 to 19:55 UTC
The uplink is 436.291 MHz and the downlink is 145.825 MHz, both NBFM. You should hear the downlink easily on a hand-held for most elevations.
Note that because of the Doppler on the uplink, you should set your uplink frequency to 436.286 for the first half of the pass and 436.296 for the second half.
On 8 July we used a 2-m 1.5W hand-held with a quarter wave monopole to transmit to Sunsat when it was at 18 degrees elevation. The signal was transponded down on 70 cm to our ground station, and was of good quality. This is not a quantitative measurement, but is the first test that verifies the good sensitivity of the 2-m receiver on Sunsat. The good sensitivity means that the RF system on Sunsat is likely to be good enough to support the planned Parrot operation of Sunsat for schools programs. The parrot will recieve an uplinked 2-m signal, store it digitally, and then re-play it on the 2-m transmitter. Many Amateurs have heard the strong 2-m downlink signals from SUNSAT. If all works as planned, amateurs will be able to demonstrate satellite operations at schools with a single 2-m hand-held, and children will be able to hear their own voices repeated from space. We think this will be popular as exposure to technology, and a means of stimulating interest in Amateur Radio in schools. We expect school homwbrew kits being developed to support such interests..