[email protected] wrote:
"WE" will be where our "host" is located and need to point from there the best we can. I assume we will know this info before launch? So whether or not we can aim for a certain spot is unknown until then.
At 02:59 PM 12/14/2007, you wrote:
Probably a good pointing spot would be where XM and Sirius Point their antennas - just about on the Canadian Border close to Winnipeg- Manitoba 73 Robin VE3FRH.
We will know long in advance of the launch where our subsat point will be. Intelsat will then do station keeping. As we are selected for a launch, we will be able to tell what the planned subsat will be. We will tell all of you what it is when our launch partner tells us we can. In addition, we will calculate where on the earth will be illuminated. We will calculate how much degradation there will be for users on the limbs of the earth so they can size their antennas, etc. accordingly. AMSAT is designing and will make available the terminals for the ACP. I remind that with this bird we no longer need rotors.
You will see in my upcoming journal columns that we have two flight opportunities for SDX next year. It was almost a third on a Cubesat but that is the way things go some times.
We have purchased the necessary development to enable build of code for the entire SDX and ACP in prototype form. The SDX will contain the "ultimate" HELAPS and this will be designed using the real modulator which will be worked out with Marc Franco (N2UO). We are expecting both efficiencies and linearity never thought possible a few years ago and deliverable only with the DSP based HELAPS riding on board.
We have two Lyrtech boards which have TI DSP chips and FPGA to enable us to do the work. These boards produce and use IF and we can set them up to operate on 10.7 MHz easily. We are using rapid prototyping tools that I get from work so we can quickly demonstrate this capability.
Howard has been continuously improving the SDX/Leila implementation and I want to be able to start development on the HELAPS modulator and radar pulse subtracter.
The same boards with the FPGA will enable us to build the wideband digital modulator and polyphase filter bank demodulators for the ACP in a reduced number of channels form to allow for easy algorithm development. Don't worry about all of this jargon for now. It will all be made clearer in my columns and demonstrations during the coming year.
We are only doing prototype work for now on the ACP and will only work on the IF and baseband processors for the linear transponder because we don't know the size of the linear transmitter yet. Eagle will be ~50w and Intelsat will be LOUD if we get the power we have requested and the efficiencies we expect. The ACP, even though it is all microwave, will be a hard limiting transmitter and very efficient.
Bob