[amsat-bb] Re: Google Project Loon - 2400 / 5800 MHz

Bryce Salmi bstguitarist at gmail.com
Mon Jun 17 15:31:39 PDT 2013

Thank you for sending this out Trevor. Below is a copy of what I sent out
to the local club email list earlier in the month. PART is a very fun and
welcoming club, anyone interested in attending is more than welcome.
Meetings do tend to be well attended.

Bryce Salmi
Below is a decent collection of important links to the documentation of our
project. I've also included a new link to our project being demonstrated
outside. I'll also add onto this email that we were told we had 45 minutes
to present so if you are interested in the projects technical details, *please
feel free to email me before or after the meeting with any detailed
technical questions! *We could easily fill in more than one meetings worth
of time if we presenting most of the technical details of this project.

AMSAT has sponsored a senior design group at the Rochester Institute
of Technology
to design and build an engineering prototype *Maximum Power Point
Tracker* (MPPT)
for use on the Fox-2 spacecraft aimed to launch into Low Earth Orbit around
2015. A MPPT is used to maximize the power obtained from a solar panel by
forcing the cells to operate at their most efficient voltage regardless of the
voltage required by the payload. One can also think of this as an impedance
match. This optimum voltage changes slightly with variations in solar
irradiance but changes greatly due to variations in solar panel
temperature. The MPPT also utilizes a Texas Instruments MSP430
microcontroller to communicate telemetry data with the Fox satellite
Internal Housekeeping Unit (IHU) designed by AMSAT for transmission to
Earth via ham radio. The senior design group consisting of Brenton Salmi
(KB1LQD), Bryce Salmi (KB1LQC), Ian MacKenzie (KB3OCF), and Daniel Corriero
successfully implemented an analog MPPT designed for use in orbit over the
five year mission intended for Fox-2 providing the amateur radio community
with a 3U CubeSat carrying amateur radio communications equipment. The 45
minute presentation will briefly overview the design and function of the
MPPT. A working prototype will also be present at the meeting.

Here's some more information for those interested in learning more details
about our project. There is absolutely no way that we will be able to cover
the project with much detail within 45 minutes, but we'll take what we can
get! (Thanks for the spot!) Our best efforts will be made to keep the
presentation interesting to all in attendance, technical and non-technical
alike. Maybe you could distribute some of the links of interest below as
needed, I know the paragraph above is meant to concisely describe the
project. The "detailed design" section of our EDGE website is where the
heavy-hitting technical documentation is located. Those interested in the
gritty details of the project should check out the documentation. We did
our best to absolutely flood AMSAT with as much information as possible.

*Main Documentation:*

*Technical Document (8 pages of technical information HIGHLY recommended

*Theory of Operations (In-depth technical documentation):*

*PCB Picture:*

*MPPT Testing Operational Walk-through:



Bryce Salmi,

On Mon, Jun 17, 2013 at 5:09 PM, M5AKA <m5aka at yahoo.co.uk> wrote:

> The first trial High-Altitude Balloon launches have taken place from New
> Zealand.
> Google plans to sending up 300 balloons transmitting on 2400 MHz and 5800
> MHz around the world at the southern fortieth parallel that would provide
> coverage to New Zealand, Australia, Chile, and Argentina. The company hopes
> to eventually have thousands of balloons flying in the stratosphere at an
> altitude of 20 km.
> See
> http://amsat-uk.org/2013/06/17/google-project-loon-using-2400-and-5800-mhz/
> ----
> 73 Trevor M5AKA
> AMSAT-UK website http://amsat-uk.org/
> Facebook https://www.facebook.com/pages/AMSAT-UK/208113275898396
> Twitter https://twitter.com/AMSAT_UK
> ----
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