FACTS ABOUT THE AMSAT PHASE 3-D SATELLITE

     As currently designed, Phase 3-D will receive on the  21, 145, 
436, 1270 and 5600 MHz Bands.  It will transmit on the 29, 145, 
436, 2400, 10,500 and 24,000 MHz bands.  Receive/transmit 
combinations will be programmable from Earth through the onboard 
computer and a unique RF matrix arrangement allowing one or more 
uplink receivers to be linked to one or more downlink transmitters.  
The satellite will weigh some 800 pounds at launch.  It will also be 
about 7.5 feet in diameter and about 3 feet high.  With its solar 
panels extended, Phase 3-D's "wingspan" will be over 20 feet.  Phase 
3-D's elliptical orbit will vary from a maximum height of 29,000 
miles above the Earth to a low of some 2400 miles. On-board 
antennas will offer gains in the 4 to 19 DBic range which, because of 
the spacecraft's unique three-axis stabilization, will always point 
Earthward.  When combined with on-board power capability 
approaching 600-700 watts, these high-gain antennas will produce 
effective downlink transmitter powers as high as 10-20 Kilowatts.

     As Phase 3-D's transmitters and receivers will be programmable, 
this concept will make the traditional satellite mode designators that 
Amateur satellite operators have become used to (such as Modes A, 
B, and J), virtually obsolete.  For example, on Phase 3-D, a mode 
"U/VS" will be possible.  That is, Amateurs will be able to uplink to 
the satellite on U-Band (435 MHz) while the satellite transmits 
downlinks on both V-Band (145 MHz) and S-Band (2400 MHz).  
Simply looking  at the frequency chart for Phase 3-D, it becomes 
apparent that a myriad of different combinations (like modes "C/V", 
"UL/S" and "L/SC") could all be supported!  Of course, the 
traditional Mode B, one of the most popular modes on the current 
Phase 3 satellites, will become Mode "U/V" under this concept.  It is 
expected this frequency pair will be one of the more active ones in 
the first years of Phase 3-D's lifetime.  However, as commercially 
available gear for the higher bands becomes more available and 
lower in cost, use of the "new" frequencies is expected to increase.  
When this happens, Phase 3-D's powerful receiver and transmitter 
suites for these bands will already be in orbit and available for use.

     Other experiments slated for the new satellite include a GPS 
receiver that will allow the satellite to tell ground controllers where 
it's located at any time.  Three digital cameras, tied to the 2400 MHz 
downlink, will also be included. Two of these cameras will point 
Earthward.  Another, combined with an astronomical telescope, will 
point toward the stars and planets.   

(Current as of August, 1993)	

For more information contact:

Keith C. Baker, KB1SF
1324 Fairgrounds Road
Xenia, Ohio 45385-9514 USA
"kb1sf@amsat.org"