Author Topic: A measurement of 10 MHz down to 10 uHz  (Read 16369 times)

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Offline cdev

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Re: A measurement of 10 MHz down to 10 uHz
« Reply #100 on: February 05, 2018, 02:04:56 AM »
I would recommend looking for a TruePosition surplus GPSDO, they can be found for as little as $40 on ebay.

Performance is quite decent.

Hi Bob

I hear you. Hydrogen masers are a little out of my league. Afraid I will have to stick to crystals oscillators. I hear GPS disciplined oscillators are hitting the eBay market in the 100 dollar range , maybe?? One poster said he unplugging the antenna of such a devise and it stayed withing 4 mHz for hours  compared to an atomic clock Hmmm. Rather impressive. Maybe I should start doing science instead of just talking about it and buy one of these GPS disciplined clocks. In for a penny in for a pound sorta speak. Being a 66 year old fart the time to be real is now not later.
"What the large print giveth, the small print taketh away."
 

Offline mrflibble

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Re: A measurement of 10 MHz down to 10 uHz
« Reply #101 on: February 05, 2018, 02:54:41 AM »
Also, to tune that new-found laser enthusiasm to a proper linewidth, these may be beneficial:
https://www.thorlabs.com/tutorials.cfm?tabID=f7dfa931-5afa-441b-8176-292d8735b143
https://www.rp-photonics.com/external_cavity_diode_lasers.html

Especially Thorlabs has pretty good overall information IMO.

Before you jump down the laser rabbit hole, I've been told that laser rabbit holes can be very deep indeed. Something to keep in mind while working out your hobby time & money budget.

If the hypothetical effect you want to verify grows linearly with voltage difference, then instrumentation step 1 is a no-brainer. Get a vandergraafgenerator that juuuuust gets through the door. Clear room of furniture & cats. Off you go! As you have found, beyond a certain point the cost & difficulty of precision timing goes up. The incremental cost of upgrading voltage at this point would seem far lower than the timing part. I hesitate to bring it up, but the even lower cost part to upgrade would be theory & thought experiments. Consider working out your idea to the max. If the effect whatever-it-is exists, planet earth is not the only place. What are other places you can look? Can you take previous discoveries and steal ideas there? We live on a planet with pretty cool lightning. Those water molecules in that cloud up there live at a pretty large potential difference compared to the planet below. What would be the effect of that? Same question for planets.

Gah, I was going to google a reasonable site/paper with the kind of info I was thinking of.

This just in! Our solar system could be destroyed by lightning!  ;D
http://www.systovi.com/en/faq/can-solar-system-be-destroyed-by-lightning/

Yeah well, okay, that's a solar system too I suppose. But not the one I was looking for.

Anyways, thinking some more about it, due to proximity lighting on our planet is the most practical. So given the potential difference, is there any difference that would be caused by the hypothetical effect? I dunno, marginal difference in ozone percentage? Difference in nitrogen oxides? Why go to the trouble of building stuff when you have a free lab all around you for the basic sanity checks?

Another one that comes up during the "What if?". Suppose that voltage difference is consistent with time dilation. (Nope, not going any stronger than consistent with). Then looking for parallels you can take general relativity. Dump a clock down the cliff into the gravity well, tada time dilation. And if I understood your hypothetical situation correctly then the hypothesis would be: put clock in Faraday cage, crank up the voltage, tada time dilation. Right? If so, what happens during the ramping up and down of the voltage? Does the time taken for ramping up/down make any difference? What happens when you put another Faraday cage next to it? What happens when you now also ramp up the voltage on the neighboring Faraday cage? Any predictions there? Basically you can take everything you already know from general relativity and work out the parallel case. It would be silly to ignore relativity just because it's inconvenient and forces you to think a little more. Because general relativity gives you some hints that you will now have to be prepared for inconvenient things. If you have a model that actually has an answer for that, and predicts new verifiable behavior, then I say gogogo. It has low probability, but worth a shot. If not, well ...  :-//

IMO: Biggest wins at this stage are thought experiments + inspired star gazing. After that working out the model beyond the "if voltage, then time dilation" stage. If it survives that, then up the voltage. And only then fiddle with the timing side. Possibly less fun, but more practicable. Or "stick it in at an oblique angle" again, and hope for the best. Oh well,  if nothing else you end up with more cool toys to play with, that's always a plus.  ;D
 

Offline John Heath

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Re: A measurement of 10 MHz down to 10 uHz
« Reply #102 on: February 05, 2018, 03:27:17 AM »
A Helium laser is better but that is mainly because it has a glass resonate cavity not plastic one like the red LED pointer.
Mmmh? The resonant cavity of that red laser diode would be made of semiconductor. The edges (mirrors) are formed by cleaving the crystal.

Quick reference, third paragraph here: https://en.wikipedia.org/wiki/Laser_diode#Failure_mechanisms
Quote
At the edge of a diode laser, where light is emitted, a mirror is traditionally formed by cleaving the semiconductor wafer to form a specularly reflecting plane. This approach is facilitated by the weakness of the [110] crystallographic plane in III-V semiconductor crystals (such as GaAs, InP, GaSb, etc.) compared to other planes. A scratch made at the edge of the wafer and a slight bending force causes a nearly atomically perfect mirror-like cleavage plane to form and propagate in a straight line across the wafer.
When designing experiments: more precision, less assumptions based on suboptimally-evolved-monkey-brain intuitions. I should know, I have one of those suboptimally evolved things as well. Intuition for avoiding sable tooth tigers? Check! Intuition for avoiding locations strewn with fellow primate bones? Check! Intuition for dealing with 100+ dimensional subspaces? No habla 4+-d senor!


But seriously, don't just assume stuff.

Nice find. It is a little more sophisticated than I thought. Not sure if the cheap dollar store laser pointers are horizontal or edge type as the good stuff in inside the LED case.

 Avoiding saber tooth tigers. I did a little paper on that one. More like a long post. Fight or flight response. A cave man see a saber tooth tiger and think " did my new and improved club impress the guys at the camp fire last and saber tooth tiger ,, I should leave" . That cave man waited too long multitasking so he became a lunch for the tiger. Another cave man but he is limited as he can not think if rushed or scared. You would think he would be tiger lunch for sure. No as he can not think when scared so all he does is react to what his eyes see " dangerous tiger " so he runs without waiting. He lives to fight another day. We evolved from the one that can not think . The logical one that can multitask did not make it to the benefit of tigers. There is actually a test that can be done in psychology that will lead to incorrect conclusions verifying limited cognitive abilities in the fight or flight response.
 

Offline John Heath

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Re: A measurement of 10 MHz down to 10 uHz
« Reply #103 on: February 05, 2018, 03:39:00 AM »
I would recommend looking for a TruePosition surplus GPSDO, they can be found for as little as $40 on ebay.

Performance is quite decent.

Hi Bob

I hear you. Hydrogen masers are a little out of my league. Afraid I will have to stick to crystals oscillators. I hear GPS disciplined oscillators are hitting the eBay market in the 100 dollar range , maybe?? One poster said he unplugging the antenna of such a devise and it stayed withing 4 mHz for hours  compared to an atomic clock Hmmm. Rather impressive. Maybe I should start doing science instead of just talking about it and buy one of these GPS disciplined clocks. In for a penny in for a pound sorta speak. Being a 66 year old fart the time to be real is now not later.

I hear you. I have been looking at GPSDO for a while. I could tweak up all my frequency counters and also see how stable they are over with room temperature. Can not bring myself to put a credit card number on the net. I know it is done all the time but with my luck something will go wrong. I wish there was a store where you can go and say I want this from ebay , here is your deposit. Why do we not have internet stores??
 

Offline cdev

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Re: A measurement of 10 MHz down to 10 uHz
« Reply #104 on: February 05, 2018, 03:45:27 AM »
PM user KE0LFX

He might have one he could sell you.

If you get one, this thread might be useful.

http://www.eevblog.com/forum/projects/gpsdo-loss-of-satellitesfix-troubleshooting/

Also, there is a PDF you can find on this web site which is invaluable in getting the hookup right.

http://www.packratvhf.com - I think its been moved, my old URL no longer works. If you cant find it PM me and I'll get the relevant info to you. Its very simple. 

The cards have both RS-232C (12v) and 3.3 volt serial connections.

Also here are all the (known) commands in a single page:
https://github.com/pigrew/trueposctrl/blob/master/GPSDO_commandset.h

You will need to connect to it via a serial console to tell it to start working (command $PROCEED) when its booted up, and also to get it to do a survey when you first turn it on and whenever you move its location.

I would recommend looking for a TruePosition surplus GPSDO, they can be found for as little as $40 on ebay.

Performance is quite decent.

Hi Bob

I hear you. Hydrogen masers are a little out of my league. Afraid I will have to stick to crystals oscillators. I hear GPS disciplined oscillators are hitting the eBay market in the 100 dollar range , maybe?? One poster said he unplugging the antenna of such a devise and it stayed withing 4 mHz for hours  compared to an atomic clock Hmmm. Rather impressive. Maybe I should start doing science instead of just talking about it and buy one of these GPS disciplined clocks. In for a penny in for a pound sorta speak. Being a 66 year old fart the time to be real is now not later.

I hear you. I have been looking at GPSDO for a while. I could tweak up all my frequency counters and also see how stable they are over with room temperature. Can not bring myself to put a credit card number on the net. I know it is done all the time but with my luck something will go wrong. I wish there was a store where you can go and say I want this from ebay , here is your deposit. Why do we not have internet stores??
« Last Edit: February 05, 2018, 03:54:39 AM by cdev »
"What the large print giveth, the small print taketh away."
 

Offline John Heath

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Re: A measurement of 10 MHz down to 10 uHz
« Reply #105 on: February 05, 2018, 05:29:48 AM »
Also, to tune that new-found laser enthusiasm to a proper linewidth, these may be beneficial:
https://www.thorlabs.com/tutorials.cfm?tabID=f7dfa931-5afa-441b-8176-292d8735b143
https://www.rp-photonics.com/external_cavity_diode_lasers.html

Especially Thorlabs has pretty good overall information IMO.

Before you jump down the laser rabbit hole, I've been told that laser rabbit holes can be very deep indeed. Something to keep in mind while working out your hobby time & money budget.

If the hypothetical effect you want to verify grows linearly with voltage difference, then instrumentation step 1 is a no-brainer. Get a vandergraafgenerator that juuuuust gets through the door. Clear room of furniture & cats. Off you go! As you have found, beyond a certain point the cost & difficulty of precision timing goes up. The incremental cost of upgrading voltage at this point would seem far lower than the timing part. I hesitate to bring it up, but the even lower cost part to upgrade would be theory & thought experiments. Consider working out your idea to the max. If the effect whatever-it-is exists, planet earth is not the only place. What are other places you can look? Can you take previous discoveries and steal ideas there? We live on a planet with pretty cool lightning. Those water molecules in that cloud up there live at a pretty large potential difference compared to the planet below. What would be the effect of that? Same question for planets.

Gah, I was going to google a reasonable site/paper with the kind of info I was thinking of.

This just in! Our solar system could be destroyed by lightning!  ;D
http://www.systovi.com/en/faq/can-solar-system-be-destroyed-by-lightning/

Yeah well, okay, that's a solar system too I suppose. But not the one I was looking for.

Anyways, thinking some more about it, due to proximity lighting on our planet is the most practical. So given the potential difference, is there any difference that would be caused by the hypothetical effect? I dunno, marginal difference in ozone percentage? Difference in nitrogen oxides? Why go to the trouble of building stuff when you have a free lab all around you for the basic sanity checks?

Another one that comes up during the "What if?". Suppose that voltage difference is consistent with time dilation. (Nope, not going any stronger than consistent with). Then looking for parallels you can take general relativity. Dump a clock down the cliff into the gravity well, tada time dilation. And if I understood your hypothetical situation correctly then the hypothesis would be: put clock in Faraday cage, crank up the voltage, tada time dilation. Right? If so, what happens during the ramping up and down of the voltage? Does the time taken for ramping up/down make any difference? What happens when you put another Faraday cage next to it? What happens when you now also ramp up the voltage on the neighboring Faraday cage? Any predictions there? Basically you can take everything you already know from general relativity and work out the parallel case. It would be silly to ignore relativity just because it's inconvenient and forces you to think a little more. Because general relativity gives you some hints that you will now have to be prepared for inconvenient things. If you have a model that actually has an answer for that, and predicts new verifiable behavior, then I say gogogo. It has low probability, but worth a shot. If not, well ...  :-//

IMO: Biggest wins at this stage are thought experiments + inspired star gazing. After that working out the model beyond the "if voltage, then time dilation" stage. If it survives that, then up the voltage. And only then fiddle with the timing side. Possibly less fun, but more practicable. Or "stick it in at an oblique angle" again, and hope for the best. Oh well,  if nothing else you end up with more cool toys to play with, that's always a plus.  ;D

Thank you for a quality response. Can do this justice without breaking it up into 5 or 6 responses. And also thank you for reading the complete thread to understand the reason for doing a voltage frame of reference test for time dilation. As a science nerd you learn to keep your cards close to your chest as people will laugh. In your case I will put the cards on the table. A little teaser , Coulomb is Q * Q /  R^2 for distance.  This means a positive charge in a vacuum of virtual + an - charges , quasi quark or virtual positronium what ever your cup of poison is , will have a greater effect on negative charges than positive charges of a vacuum.  It is written in Coulomb's law Q * Q/R^2. We lost symmetry for the net density of a vacuum. Einstein had something to say about gravity caused by a change in the shape of space. The teaser is just maybe Special and General relativity could sit under the same roof. Who needs the complication of a metric tenser if it turns out to be as easy as Coulomb's law. However without establishing a clear voltage coefficient for time dilation it is just wishful thinking.

I will be cutting little bits of your post out to respond to your other points. Hey there is no hurry so why rush. 
 

Offline mrflibble

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Re: A measurement of 10 MHz down to 10 uHz
« Reply #106 on: February 05, 2018, 09:17:58 PM »
Hey there is no hurry so why rush.
Indeed. If you have some time, you might enjoy these:

 

Offline John Heath

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Re: A measurement of 10 MHz down to 10 uHz
« Reply #107 on: February 06, 2018, 12:52:39 AM »
Yes you have to love Feynman. He has the ability to put things in a way that most get it the first time. When I watch a Feynman video I can not help but think of Art Carny , I am sure I misspelled that. The honey mooners series on TV in the 1960s with Jacky Gleason and Art Carny. There is a stand up comedian in Feynman that wants to come out and it is Art Carny in my mind , ha. Is it just me?
 


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