Hi
> On Nov 17, 2017, at 4:26 PM, Patrick Barthelow <[email protected]> wrote: > > From me, Pat a newbie, second post: > > A new project, STEM opportunity. A STEM/CitizenScience/Ham Space Science > project. Kids welcome. > In formative stages so this is for internal discussion, not for public > announcements yet. > Will do a frequency measurement of a Cubesat at about 437 mhz that will > orbit the Moon in 2018. > Can be received by modest yagi antennas while orbiting the moon. That sounds like a pretty high ERP … Of course your definition of a modest antenna may not be quite the same as mine :) Consider that there *are* SNR implications when you get into your accuracy requirements below. > Challenge is to get/use/build precision frequency references and counters, > and measure the carrier frequency. Cesium, Rubidium, MASER, GPS based, > commercial standards, and their derivations all welcome. > Have found 4 (and More) more hydrogen line masers in diverse locations > around the world, who wish to participate. > USA, Netherlands, South Africa, Australia, Mexico, and other locations have > expressed interest. > > I am a member of Team Alpha Cubesat. We and some other teams are in the > NASA CUBEQUEST challenge. Launching next year a 6u cubesat to lunar > orbit. I am not an expert at the freq measurement aspect of this, so, I am > a Newbie. With tons of questions, but I was surprised how quickly a check > of the world's Hydrogen line MASERS got many to offer to come on board. > MASER is overkill, but that is OK. The MASER is a cute device. It is not an accurate device by it’s self. It is a very *stable* device. Yes, that is a subtle distinction. In this case I think it is a pretty important one. > The Chief Scientist of the project is > in the USA and wants to make measurements to the HZ level, at 437 mhz so > with MASERS and Cesium, Rubidium we are overkill but it could generate > STEM/Citizen Science participation. That is what we are doing. So the > satellite will be on 437.5 mhz plus minus doppler. We have to measure > its received freq to 1 HZ or less. Ok, 1 Hz at 437.5 MHZ is roughly 2 ppb. That is pretty much “slam dunk” accuracy with a GPSDO. Much easier to obtain and set up in a school environment. The key will be orbit estimation for the +/- doppler part of it. Orbit estimation is not quite a slam dunk sort of thing. The GPSDO would also give accurate location. Even with good orbit data, the solution still requires a good location estimate. > So I talked to the chief scientist, > and we decided to go with a public STEM related program I’ve been down the road (from scratch to running) on STEM competitions. The KISS principle is one to keep in mind. At the same time you *do* want a topic that presents a challenge. > with it. [PLEASE > DO NOT GO PUBLIC YET This *is* a public list, it’s “out” now. > this is confidential for now.] Announcement of a > competition for anyone to measure the frequency of the sat as it is in moon > orbit. So I decided to check with about 5 geographically diverse located > MASERS. ( Australia, South Africa, UK, Holland, Mexico and USA, and got > or am getting buy-in from them to make the measurement. I was surprised > they did not just say go away... a half million dollar MASER is, or should > be busy with similar but necessary measurements from paying customers. > Overkill, I admit, but it is a chance for Citizen Science publicity, > Popular Science, STEM, etc.. > > > Anyway I got a bunch of MASERS to participate and will develop a website > for people to measure the freq and send in their "answer". We will have > (are looking for) sponsors that will pay prizes or wall paper awards, for > very close accurate measurements. > This is like a modern day Frequency Measurement Test that ARRL did years > ago. I will in fact call ARRL to see if they want to play in this. I will > CC others to see if they want to play. Other frequency references used may > be commercial variations of > Cesium Beam and Rubidium references. But the King Kong in accuracy is the > MASER. I got to learn a bit about the MASER they had at Arecibo when I was > there. And now know a school in Europe a Technical Instrumentation > school, that offers a project to build a Hydrogen Line Maser using modern > simpler, cheaper methods and hardware. > > Arecibo may play on this event next year. So, you only need modest yagis > to pick up the Sat at moon distances on 437.5 mhz should be fun... > The Goldstone MASER; above: > >> >> https://www.nist.gov/pml/time-and-frequency-division >> https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwv >> http://tf.nist.gov/stations/wwvtimecode.htm >> https://www.nist.gov/pml/time-and-frequency-division/time-se >> rvices/history-radio-station-wwv >> >> https://www.nist.gov/pml/time-and-frequency-division/time-se >> rvices/wwv-and-wwvh-digital-time-code-and-broadcast-format >> >> http://tf.nist.gov/phase/Properties/main.htm > > See/Search Also: > Precise Time and Time Interval Clocks Time Frames and Frequency, James R. > Clynch Navy Postgraduate School. > Introduction to Frequency Standards by Lindon Lewis > > > Interested? Get back to me to start planning for the 2018 launch, and > cubesat in lunar orbit, exact date not known. > > Best, 73, Pat Barthelow AA6EG > apol <[email protected]>[email protected] > Bob > > *"The most exciting phrase to hear in Science, the one that heraldsnew > discoveries, is not "Eureka, I have found it!" but:* > "That's funny..." ----Isaac Asimov > <masergoldstone.jpg>_______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
