NiCd Battery Analysis: Historical and Modern

Greetings all!

I’d like to tell you all about a project going on to revive/document Larry Keyser’s engineering on matched NiCd cells that made up the batteries for UO-11 and other amateur payloads from that era. This would be up to four of the AO-teens payloads, and at least one other smallsat. The batteries were very reliable, exceeding amateur and professional expectations. 

Selecting cells for a battery takes testing and an understanding of the basics of the underlying chemistry and physics. Early amateur payloads got a great deal here with some surplus cells from avionics and/or medical surplus. These cells were high quality to begin with, but that’s not enough by itself to ensure a lengthy lifespan in space. 

Larry Keyser knew how to match the cells to make batteries that would last a long time. The overall strategy was to select batteries that were similar. Not necessarily the best performers in the batch, but the best matched cells.

Temperature performance and curve matching were both considered critical. Furthermore, the batteries were scanned to eliminate those with internal structural anomalies and faults. 

Several of us at ORI are preserving, publishing, and extending this work. We have some advantages, in that modern battery analysis equipment is much easier to use and more capable than what previous volunteers had to work with. ORI has a modern battery analyzer, capable of working up to 44 volts, available for community use.

Modern test equipment produces much higher resolution charge/discharge curves, and temperature monitoring is incorporated automatically. Measurements can be automated in ways that Larry didn’t really have available at the time he was working on this for AMSAT and other missions. 

We have software tools and languages (Python, MATLAB) that make curve matching easier. There’s never been a better time to save and publish a summary article about Larry’s achievements and what we, as modern hams, can do to improve upon it. 

This is all open source work through Open Research Institute. It’s offered for free to anyone or any organization that wants to use it. NiCd batteries aren’t as hip or cool as Lithium Ion, but they are reliable in space, and this ongoing battery project will produce both data and actual physical battery packs that amateur/educational missions may want to consider using. 

The battery analysis equipment is capable of doing any battery chemistry, so if you have an open source amateur satellite project in mind that needs battery analysis support, ORI is here to help out with that. 

Want to get involved?

Dual-Band Feeds Update

My background is baseband and algorithm development, but the RF side is where the signals meet and exceed the sky. I have only the deepest respect for those that are talented here and give generously of their time for amateur satellite project success. We owe so much to Kent Britain, Paul Wade, and many others.

There are two designs for Phase 4 dual band feeds in the repository linked here. They are dual-band feeds, best used in dishes.

https://github.com/phase4ground/documents/tree/master/Engineering/Antennas_and_Feeds

The first one I want to introduce you to is the 5 GHz up, 10 GHz down. This feed was designed by Paul Wade W1GHZ, has lab results, has been manufactured in amateur machine shops, and has been 3d printed/metallized. This feed was demonstrated at amateur and IEEE conferences.

The second is 10 GHz up, 24 GHz down. This feed is another design from Paul Wade W1GHZ. Preliminary lab results are in progress and published in the repository. More to come! ORI bought 15 of them and is interested in putting them into the hands of amateurs that will use them and report back. Three have been sent out so far, and we are looking to send out more.

While the baseline Phase 4 design is “five and dime”, the goal of ORI is to use any and all microwave bands that we can. I think we are all aware of how much pressure our microwave bands are under from commercial interests.

The system design is extensible to 10/24, so we needed a feed for this.

If you want to contribute or participate, then please visit

https://www.openresearch.institute/getting-started/

Thank you to all that have helped make this possible!

-Michelle W5NYV

26 March 2021 Engineering Report

Here is a visual walkthrough of the features on the TEBF0808 UltraITX+ Baseboard for Trenz Electronic TE080X UltraSOM+, presented by Paul KB5MU and Michelle W5NYV.

These stations are available to the community from Open Research Institute’s Remote Labs. We currently have two sets of gear and are procuring two more.

The Trenz platform allows for full access to the FPGA, power reduction work, and thermal modeling. All are extremely important for space applications.

We also have the Xilinx development board for the Ultrascale, for preliminary work.

The FPGA module goes in the lower left empty square with the high-density connectors.

The FPGA module has a heat sink, called a heatspreader, that is a machined metal plate. It attaches to the FPGA module with screws. However, it needs an intermediate layer to conduct the heat from the FPGA to the metal plate. The plate is designed to fit many different modules, and there’s a gap between the metal plate and the top of the components on the FPGA module.

This gap is usually filled with a specific gap-filling thermal paste.

Which happens to be out of stock, all over the world.

So, of the four stations we’re settting up, one will be fitted with a thermal adhesive film. This comes in sheets and can be cut to size. It can be used for space, so as we dial down the power consumption with code adjustments, we can measure the thermal results with something that is appropriate for the space mission.

The other three will get gap-filling goo directly from Trenz. This is the only way to preserve the warranty on these expensive modules, so it’s not a bad choice. And, this gives us something to compare the sheet against. We’ll test both in thermal modeling and chamber.

-Michelle W5NYV

How To Leverage Amateur Radio In Space

Compiled by Michelle Thompson W5NYV, Patrick Stoddard WD9EWK, Douglas Quagliana KA2UPW, and Pierros Papadeas SV1QVE Director of Operations at Libre Space. Please contact any of us with questions, comments, additions, and corrections.

w5nyv@arrl.net
wd9ewk@amsat.org
dquagliana@gmail.com
pierros@libre.space

Version: March 22, 2021

Introduction

Who is this document for? You may belong to one or more of the following categories.

You want to deploy an amateur radio spacecraft.
You want to include amateur radio operators.
You want to use amateur radio frequencies.
You are interested in using SatNOGS.

Amateur radio is about the operators. The licensees in the amateur radio satellite service are individual people. They have a license not just to use communications resources in space, but they are also licensed to control spacecraft, with the permission of the spacecraft license holder.

The Amateur Radio Satellite Service is a non-commercial communications service available worldwide. It is dedicated to education, experimentation, and the amateur use of space.

The VHF international amateur satellite frequency allocation is 144.000 MHz – 146.000 MHz with 145.800 MHz – 146.000 MHz being recommended and preferred. The UHF international amateur satellite frequency allocation is 435.000 MHz – 438.000 MHz. There are other allocations on other bands, but these are the most heavily used at this time.

Providing a spacecraft that is useful to the amateur radio satellite service is not difficult, but there are aspects that may be non-intuitive coming from a commercial or academic background. There are expectations from the amateur radio community of spacecraft that operate on amateur radio bands.

The starting point is https://www.iaru.org/reference/satellites/

This site contains a wealth of information about Amateur Radio in Space. Carefully reviewing the entire site will put your project and your team in the best possible place to leverage the global amateur radio satellite service.

Once this set of documentation has been read, then community standards can be adopted.

Community Standards

The advice following about community standards is hard-won. If this advice is followed, the amateur radio aspects of your project have a much better chance of being successful.

1) Use forward error correction for digital downlinks. Use open protocols and open source.

2) Test over the air, as soon as possible, in the lab, on the ground, well before launch.

3) Clearly describe how amateur radio operators will receive your signal. Operators of satellites in the amateur-satellite service must publish full details of their modulation, encoding and telemetry formats and equations before launch. Publish details long enough in advance so that amateur radio operators can implement and test receiver designs. Use Science-Technology-Engineering-Math (STEM) educational organizations to get the word out. Use your local AMSAT Societies and related groups to get the word out. Describe the air interface as early as possible, even if this is before any software is ready.

4) Make and publish a recording of your telemetry signal to allow amateurs to test demodulation and decoding of your signal.

5) What’s in this for amateur radio operators? What is the added value of the project for the ham radio community? Is there an amateur radio transponder available for general use? If not, then support from the amateur community may be very low.

6) Incorporate SatNOGS.

SatNOGS has a very useful guide for satellite builders that want to use amateur radio.

https://wiki.satnogs.org/Satellite_Operator_Guide?fbclid=IwAR2gE0q8XlWN3HatnLPuVIo9-Y3TFq2uzAqgWN2O7ErjWCYymTrbS6cEbD0

Thank You

If you are reading this, you know that forward error correction or changing frequencies can’t be done at the last minute. The amateur satellite community can be highly valuable active participants in your satellite mission, if they have the information they need about the project.

If the project provides useful communications services and engaging opportunities to amateur operators, then the benefits are plentiful and powerful. Announcing amateur radio plans early enough to get engagement and quality feedback, and publishing all the details, are the key concepts.

Do you know of a team that is starting to look at using amateur radio on their spacecraft? Please pass this along to them.

Amateur Space Radio Exhibit to host ORI Technical Demos at Ham Expo March 2021

Please visit the Amateur Space Radio exhibit at the upcoming Ham Expo, 12-14 March 2021.

https://www.qsotodayhamexpo.com/

Amateur Space Radio is any amateur radio activity that has to do with space. It could be satellites, ionospheric sounding, ground stations, any AMSAT activity, schools, citizen science, radio astronomy, and more.

Exhibit support website is located at https://amateurspace.radio/

Space Radio is fun and accessible. There is room for people that want to operate satellites. There is room for advanced experimenters improving the technology. There is room for people that buy commercial equipment. There is room for DIY and open source. And, there is room for you!

Saturday’s Space and Satellite Track features eight talks that cover all aspects of Space Radio. How to get started with equipment you already own, an introductory talk that opens up all of the magic of satellite operations, a deep dive into current microwave band digital transponder technology, a history of GEO projects at AMSAT, an explanation of what is required to support an international volunteer team working on FPGA development for amateur satellite work, some very good regulatory news for the United States, how we are engaging students in amateur satellite, and what we need to do about space junk.

All of the talks will be available after Ham Expo, but at the event you will get to interact with the presenters directly, asking them questions, live. Many of these speakers will be at the Amateur Space Radio booth for breakout sessions.

The breakout session schedule includes Getting Started, Roving Operations, JAMSAT, Tech Talk, Tech Demos with Open Research Institute and others, ARDC, Space Weather with TAPR, and an Antenna Session with Kent Britain. We have a couple of open tables and if you want to see something discussed, then please come by and we will set something up.

The Amateur Space Radio exhibit in the Expo doesn’t just have breakout sessions with subject matter experts. It also has nine hours of video content from around the world. These videos include highlight reels, tutorials, and presentations. They cover activity ranging from FM satellite operations to antenna design to advanced propulsion experiments and more. We are playing the world class GNU Radio workshop from Dr. Estevez about decoding satellite transmissions on Sunday with all of the resources needed to participate, linked at the booth.

Our video playlist is available on YouTube from a link at front of the booth. This allows on demand viewing. The schedule for when they will be shown during the Expo is at the booth.

We have two social events this year. Friday night is a custom electronic dance set from John Brier. The recording will also be available through a link at the booth. John Brier is an active satellite operator and educator and is also an electronic dance music musician.

Our second social event is an online scavenger hunt with an Around the World Theme. The event starts at 7pm US Pacific tonight, Saturday, the 13 of March, and will be conducted through Zoom by Watson’s Adventures. If you want a ticket, come to Amateur Space Radio and find the Watson table. First come first serve. If you cannot use your ticket please return it or find someone who can. The adventure will start at 7pm US Pacific time sharp, so make sure to join ahead of time so you won’t be left out. We will close the table when we have given all tickets out.

If you want to learn more about Amateur Space Radio, and stay in touch, please use the Register Interest on our main banner at Ham Expo. We think space is the most exciting part of the amateur radio hobby and we want to hear from you on how to best support it moving forward.

Thank you to Ham Expo and the satellite community for making this exhibit such a success. Please welcome our speakers, and see you at the booth!

Welcome to Ham Expo March 2021

Here is the Schedule for the Space and Satellite PresentationTrack in Space Radio Auditorium. ORI is proud to have such good representation at this event. Please visit the Amateur Space Radio booth at QSO Today Virtual Ham Expo for our technical demonstrations, watch video presentations, and to visit with other amateur satellite enthusiasts. This event will be a big highlight of the year for amateur radio!


Watch the Track Intro Video below:

Please visit the Ham Expo website to register for the event.