Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Bob kb8tq]

Hi


> On Nov 18, 2017, at 5:38 AM, Magnus Danielson  
> wrote:
> 
> Hi,
> 
> On 11/18/2017 02:16 AM, Hal Murray wrote:
>> kb...@n1k.org said:
>>> 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.
>> What is the orbital period?  It would be fun to plot the Doppler over time
>> and see if you can get something that looks like a big chunk of an orbit.
>> Ugh.   What is the Doppler due to the Earth's rotation?
> 
> You need to compensate for your position, because it would lower due to 
> longitude naturally.
> 
> Yeah, and then the moon isn't in perfect circular orbit either.

Effectively you have multiple things spinning around in various ways. The 
“orbit” isn’t a single thing
in this case. Earth gravity “lumps and bumps” impact GPS orbits. There are a 
lot of things to have
lumps and bumps in this caae. Depending on the orbit relative to this and that, 
you may have a fairly 
limited observation time on each pass. This and that accumulate on the “dark” 
part of the orbit, but 
you can’t observe it as it happens. You simply see a jump (versus prediction) 
at the start of the next
pass.

Bob

> 
> The sat is also in a not so perfect orbit, so it would also needed to be 
> measured and characterized.
> 
> Fun problem.
> 
> I realized that my on the fly least square algorithms would be nice to adapt 
> to this problem.
> 
> Cheers,
> Magnus
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Tim Shoppa]

Orbital determination from Doppler shift is, IMHO, a far more interesting
and fun STEM project than measuring an absolute frequency. And it does not
require MASERs, it only requires low-grade amateur equipment.

Amateur "Crowdsourcing" of orbital data goes at least as far back to ARRL
collecting Sputnik reception reports both by traffic nets and audio tape.

Doppler shift for a VHF transmitter in low earth orbit is several 10's of
kHz over a period of minutes and this pass-information is incredibly useful
for orbit determination.

And science and technology students have been participating in these
determinations for decades too. A very nice review of the work done 25
years ago by students, was published in QST by N6XT:
http://www.setileague.org/articles/ham/kepler.pdf

Tim N3QE
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Attila Kinali]

On Fri, 17 Nov 2017 13:26:18 -0800
Patrick Barthelow  wrote:

>  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 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.

Is there a scientific experiment behind this? Or is it just a cool
thing to show?


> 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.

It's not like you are taking away maser-time from someone else.
At most you are using one of the free output ports of the distribution
amplifier.

> 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.

They are still running those. And quite a few get within 1Hz under more
difficult conditions than measuring a satellites frequency.

> 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.

Oh? Really? Which school is that? And is the documentation to this
project available somewhere?


Attila Kinali

-- 
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering.  -- The Doctor
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Magnus Danielson]

Hi,

On 11/18/2017 02:16 AM, Hal Murray wrote:


kb...@n1k.org said:

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.


What is the orbital period?  It would be fun to plot the Doppler over time
and see if you can get something that looks like a big chunk of an orbit.

Ugh.   What is the Doppler due to the Earth's rotation?


You need to compensate for your position, because it would lower due to 
longitude naturally.


Yeah, and then the moon isn't in perfect circular orbit either.

The sat is also in a not so perfect orbit, so it would also needed to be 
measured and characterized.


Fun problem.

I realized that my on the fly least square algorithms would be nice to 
adapt to this problem.


Cheers,
Magnus
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Ole Petter Rønningen]

Pat,

I am not a ham, but would be interested in participating if there is someone in 
my neck of the woods that needs access to timing gear. I am in western norway, 
near stavanger. I have a hydrogen maser and many other precision oscillators.

Ole

> 17. nov. 2017 kl. 22:26 skrev Patrick Barthelow :
> 
> 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.
> 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 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.   So I talked to the chief scientist,
> and we decided to go with a public STEM related program  with it. [PLEASE
> DO NOT GO PUBLIC YET 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 lo...@gmail.com
> 
> 
> *"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
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the 

Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[jimlux]

On 11/17/17 5:16 PM, Hal Murray wrote:


kb...@n1k.org said:

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.


What is the orbital period?  It would be fun to plot the Doppler over time
and see if you can get something that looks like a big chunk of an orbit.

Ugh.   What is the Doppler due to the Earth's rotation?



not huge.. Earth is 40,000 km circumference (thank you Napoleon and the 
Cassinis), so at the equator the velocity is on the order of 500 m/s


Doppler is about 600 Hz from earth rotation.

1ppm at mid latitudes

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Bob kb8tq]

Hi

As you get into a bigger array, your antenna pointing / tracking requirements 
become more exotic. I doubt that your 8 X array antenna has to do much more 
than track the moon, I could be wrong ….

Bob

> On Nov 17, 2017, at 8:14 PM, Azelio Boriani  wrote:
> 
> With 197dB of path attenuation and, say, 1W or 2W of transmitter
> power, I think that a modest antenna is insufficient. The usual yagi
> array for this distance is made by 8 27-element antennas like this:
> 
> 
> On Sat, Nov 18, 2017 at 12:54 AM, Bob kb8tq  wrote:
>> Hi
>> 
>> 
>>> On Nov 17, 2017, at 4:26 PM, Patrick Barthelow  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 

Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Hal Murray]

kb...@n1k.org said:
> 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. 

What is the orbital period?  It would be fun to plot the Doppler over time 
and see if you can get something that looks like a big chunk of an orbit.

Ugh.   What is the Doppler due to the Earth's rotation?


-- 
These are my opinions.  I hate spam.



___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Azelio Boriani]

With 197dB of path attenuation and, say, 1W or 2W of transmitter
power, I think that a modest antenna is insufficient. The usual yagi
array for this distance is made by 8 27-element antennas like this:


On Sat, Nov 18, 2017 at 12:54 AM, Bob kb8tq  wrote:
> Hi
>
>
>> On Nov 17, 2017, at 4:26 PM, Patrick Barthelow  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:
>>
>>>
>>> 

Re: [time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[Bob kb8tq]

Hi


> On Nov 17, 2017, at 4:26 PM, Patrick Barthelow  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
>> 
>>