[amsat-bb] Was HEO naivete; now GEO rideshare frequency choice, etc.

Andrew Glasbrenner glasbrenner at mindspring.com
Sat Feb 7 09:38:10 PST 2009

Bear with me as I try to clear up some misunderstanding about the 
frequencies proposed for the GEO rideshare proposal. Hopefully Tom will 
chime in here if and when I get something wrong; the proposal was his. As he 
will probably tell you I was not his biggest supporter, but I think I've 
come to understand why he made the choices he did. Keep in mind Tom's 
proposal was just that, a proposal. Even he described it as a strawman 

There were a few different driving factors for this rideshare proposal. One 
was the real estate available to us. We were offered a few boxy shaped areas 
on the order of 12 to 18 inches on a side, the exact numbers escape me. 
There would not have been much room for any sort of gain antenna for lower 
frequencies, which unlike a cubesat, is really required at GEO altitudes and 
amateur array sizes and typical power levels.

A second driving factor was funding. The initial suggested costs rapidly 
grew to the point where this could not be accomplished strictly with amateur 
funding, and we would have to solicit support from a governmental agency. We 
would need a carrot for them to justify their funding, and that carrot was 
emergency communications. The usefulness of such a system would require that 
some decent amount of data be moved, and the required groundstation be small 
and portable. An additional factor was the assumption that a ground station 
using a small dish might also be useful for allowing hams in CC&R restricted 
homes to participate on the sly outside of times of emergencies, by 
masqerading as a TVRO dish as protected by FCC rule. (I personally had 
reservations about this last line line of thinking regarding CC&Rs and the 
TVRO exemptions).

There was also concern about interference to the primary spacecraft 
frequencies, so the frequencies suggested were driven by what were hoped 
would provide the least amount of possible interference to our landlords on 
the satellite. Any interference at all would probably mean the end of our 

As discussions progressed, there was some dissension among the BOD about the 
frequencies chosen and the digital versus analog issues. Tom revised the 
microwave system design to include both analog and digital modes. More link 
analysis by others showed we could possibly go as low as 1.2 GHz and 435 MHz 
for some services, but not at the same ground station size or the same 
amount of bandwidth. These would likely have been analog systems, and their 
inclusion may have been to the detriment of the microwave services that were 
the carrot -that would pay for the launch-. Frequency selection was a big 

Warning, more of my personal opinion ahead! In the end, it was a mostly moot 
exercise because our landlord found another tenant for the immediate launch 
who could pay the rent out of pocket. We may have additional opportunities 
down the road, but the price tag will not likely ever get smaller. We 
realized we have not much experience at going to government for financial 
supoort, and that will have to be addressed before we try this again. We'll 
need someone who knows how to write grant proposals to help us. If this is 
you, please directly contact one or all of the senior leadership. I 
personally am also not sure we have the manpower to commit to a large 
short-fuse project.

Some good things did come out of this exercise. As a result AMSAT has an 
engineering task force who is now coordinating the creation and cataloging 
of individual modules that can be used to seize very short term 
opportunities for flight. Personally, I envision us placing secondary 
packages on larger, funded satellites, as the best way to orbit in the 
future. A transponder on a GPS satellite, or a FM repeater on a university 
nanosat, or a digipeater on a cubesat...this I believe is our widest and 
most direct path to the orbit. We should also expand on leveraging our 
capabilities as a distributed telemetry collection service as a means to 
acquire space for secondary packages for our own use. Delfi C-3 is a good 
analog of what our future with the cubesat community should look like.

Meanwhile, there are several of us who are very active in trying to identify 
these flight opportunities, but we could use more help. We have a few things 
in the works, one of which is not LEO, but we are not at a point were we 
could discuss them openly. ( A favorite saying of mine, first rule of fight 
club is we don't talk about fight club, at least until we think it's safe) 
We have many members that work in aerospace and if you are one of them and 
you think there may be an opportunity to fly a package on one of your 
projects, PLEASE contact myself or one of our other officers directly.

To the other BOD members and involved parties, I apologize if you think I 
have misrepresented anything; please feel free to offer corrections directly 
to the group.

73, Drew KO4MA
AMSAT-NA VP Operations and Director

More information about the AMSAT-BB mailing list