I'm glad Mode J is on the agenda. Most of the birds that have launched recently and are scheduled to launch in the near future have 2m downlinks. Here in Southwest Washington, DC, about a mile from the Capitol, there's an awful lot of QRN on 2 meters. 70cm downlinks are much easier to hear. There is QRM from the military EPLRS system on 70cm, but the noise blanker is rather effective on reducing that.
73,
Paul, N8HM
On Fri, Feb 14, 2014 at 6:53 PM, Anthony Monteiro aa2tx@comcast.net wrote:
On 2/14/2014 4:57 PM, Michael wrote:
OK then, I have a legitimate satellite question. Is Fox 2 going to be a linear bird? See, I have some confusion on this....
Hi Michael,
Good question. I think I can clear this up.
The main point of Fox-2 is to develop and fly an advanced, software defined transponder (SDX.) An SDX can be programmed to be any kind of transponder. It will be a linear, inverting, mode-J transponder by default.
We would also like to try some new and interesting digital modes perhaps including digital voice which would be my personal favorite. That is the tremendous flexibility you get with an SDX. You can change the transponder in software.
ARISSat-1 was our first attempt at an SDX and it worked very well. It could only be programmed on the ground though. The SDX for Fox-2 will be programmable in orbit.
Fox-2 will be a 3U CubeSat (3x the size of Fox-1) providing a lot more power and space for the electronics.
The source of confusion may be because we are building four Fox-1 flight units. The idea is to have them available and ready to fly so we can easily team up with universities that want to fly science missions and get free launches. Building them all at once is also a much cheaper way to build satellites.
All four Fox-1 units will have the same hardware and avionics. The universities will supply their experiment cards and the software can be customized for each satellite as needed.
Once the Fox-1 flight models are built, the engineering team can begin working on Fox-2. That should start this year.
The status of the Fox-1 satellites is as follows:
Fox-1 (Fox-1A) is scheduled to fly on NROL-55.
RadFxSat (Fox-1B) is a joint project with Vanderbilt University. It has already been accepted into the NASA ELaNa program but it has not been assigned a launch yet.
Fox-1C and Fox-1D are not currently assingned.
OK?
Best satellite DX and 73, Tony AA2TX
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