Author Topic: Why are rubidium frequency standards so expensive now?  (Read 4385 times)

0 Members and 1 Guest are viewing this topic.

Offline JBaughb

  • Regular Contributor
  • *
  • Posts: 85
  • Country: us
  • Country: us
Why are rubidium frequency standards so expensive now?
« on: May 11, 2015, 11:10:34 pm »
These were like $30-50 a couple years ago, pulled from old test equipment. Now they're selling for $200+ Why has demand increased so drastically? Has something specific happened, like a novel new use for them, or maybe supply is limited compared to a few years ago?
 

Offline PedroDaGr8

  • Super Contributor
  • ***
  • Posts: 1278
  • Country: us
  • Country: us
  • A sociable geek chemist
Re: Why are rubidium frequency standards so expensive now?
« Reply #1 on: May 12, 2015, 12:04:54 am »
These were like $30-50 a couple years ago, pulled from old test equipment. Now they're selling for $200+ Why has demand increased so drastically? Has something specific happened, like a novel new use for them, or maybe supply is limited compared to a few years ago?
Much of these rubidium standards were pulled from decommissioned cell phone cabinets. There was a flood on the market due to the change over from 3G to LTE, many cabinets were upgraded and the old rubidium standards were replaced. These found there way on ebay. With a huge supply, prices dropped. Now that most of the conversion work is done there is less supply and prices have gone back up.
The very existence of flamethrowers proves that some time, somewhere, someone said to themselves, "You know, I want to set those people over there on fire, but I'm just not close enough to get the job done." -George Carlin
 

Offline JBaughb

  • Regular Contributor
  • *
  • Posts: 85
  • Country: us
  • Country: us
Re: Why are rubidium frequency standards so expensive now?
« Reply #2 on: May 12, 2015, 01:25:28 am »
That makes so much sense. Thank you. Maybe I should wait till 5G comes out....see if prices drop again  :)
 

Online blueskull

  • Supporter
  • ****
  • Posts: 12048
  • Country: cn
  • Country: cn
  • Power Electronics Guy
Re: Why are rubidium frequency standards so expensive now?
« Reply #3 on: May 12, 2015, 01:33:10 am »
Still, spending 200+ for a used one is making sense. A new one requires 1300+, and the designed lifetime is 20 years. If you can find one that has been working for less than 5 years, then spending 200 for one is a good deal.

I got mine for 150 bucks, and it was made in 2004, while I got it in 2011. For a 7 yrs old device designed to serve 20 years, it worth its price tag. It locks in 30 secs, and it magnitudes better than OCXOs, and is tunable and GPS syncable.

Also, the cheap ones are usually FE5680 devices, which are quite old. If you can get a X72 or SA series ones for under 250, then you made a nice deal.





Bo
 

Offline edpalmer42

  • Super Contributor
  • ***
  • Posts: 1606
  • Country: ca
  • Country: ca
Re: Why are rubidium frequency standards so expensive now?
« Reply #4 on: May 12, 2015, 01:39:31 am »
There were a few reasons why the Rb units were cheap.

There was the glut of units that Pedro mentioned.  Some of them had been in service for a number of years and might have been approaching end of life.  It's also worth remembering that the old equipment was treated like scrap metal so there's no telling how badly it was abused.  Hard to believe that anything survived being dropped, having things dropped on them, being left out in the rain for who knows how long, etc.

Actually, compared to buying a new Rb standard, paying a few hundred dollars is still a good deal.  I guess we got spoiled!

Ed
 

Offline RickBrant

  • Supporter
  • ****
  • Posts: 105
  • Country: us
  • Country: us
Re: Why are rubidium frequency standards so expensive now?
« Reply #5 on: May 12, 2015, 02:08:18 am »
I got a Trimble Thunderbolt while they were $95.  ;D

The monitor program shows it's running at a few tens of ppt.

The most fun I've had with it so far is to run its 10 MHz output into the "external reference" input of my freq counter. Now the freq counter has a timebase accurate to a few tens of ppt. :D
"banging meter needles into stop pins since 1965"
 

Offline ivan747

  • Super Contributor
  • ***
  • Posts: 2013
  • Country: us
  • Country: us
Re: Why are rubidium frequency standards so expensive now?
« Reply #6 on: May 13, 2015, 03:23:56 am »
These were like $30-50 a couple years ago, pulled from old test equipment. Now they're selling for $200+ Why has demand increased so drastically? Has something specific happened, like a novel new use for them, or maybe supply is limited compared to a few years ago?

I say it's Dave's fault! He made a video about it and they became popular and now they are charging a lot for them  :palm:

 ;D
 

Offline mswhin63

  • Frequent Contributor
  • **
  • Posts: 299
  • Country: au
  • Country: au
Re: Why are rubidium frequency standards so expensive now?
« Reply #7 on: May 13, 2015, 06:33:58 am »

I say it's Dave's fault! He made a video about it and they became popular and now they are charging a lot for them  :palm:

 ;D

Yeah co-incidental that at the release of one of the earlier EEVBlogs on the Rubidium the price when up very soon after.  ;)
.
 

Offline JBaughb

  • Regular Contributor
  • *
  • Posts: 85
  • Country: us
  • Country: us
Re: Why are rubidium frequency standards so expensive now?
« Reply #8 on: May 13, 2015, 08:02:17 am »
As far as I can tell, there are three units that keep popping up. the Symmetricom SA22c, Stanford Research PRS10, and the FEI model FE5680A.

I pulled up the data sheets for each and Im reading through them but does anyone have any info on which of these are preferable. Im sure a lot of it has to do with the specific user and their needs but are there any general things to watch out for or interesting features available on one but not the others?

Thanks.
 

Offline atferrari

  • Frequent Contributor
  • **
  • Posts: 311
  • Country: ar
  • Country: ar
Re: Why are rubidium frequency standards so expensive now?
« Reply #9 on: May 13, 2015, 09:50:10 am »
Why do they have end of life?  Aging of what, actually?  Nothing that you could overcome?
Agustín Tomás
In theory, there is no difference between theory and practice. In practice, however, there is.
 

Offline Nuno_pt

  • Frequent Contributor
  • **
  • Posts: 373
  • Country: pt
  • Country: pt
Re: Why are rubidium frequency standards so expensive now?
« Reply #10 on: May 13, 2015, 10:08:34 am »
It's easier and cheaper to build and GPSDO.
Nuno
CT2IRY
 

Online blueskull

  • Supporter
  • ****
  • Posts: 12048
  • Country: cn
  • Country: cn
  • Power Electronics Guy
Re: Why are rubidium frequency standards so expensive now?
« Reply #11 on: May 13, 2015, 12:25:23 pm »
Why do they have end of life?  Aging of what, actually?  Nothing that you could overcome?

The Rb clocks works as a PLL. The Rb cell resonates at a certain frequency (for CPT clocks, 850.2nm+6.8GHz). At resonant frequency, the transparency of metal vapor goes maximum, therefore, by exciting Rb with such a coherent light source (laser) with 3.4GHz modulated on it, you can observe CPT effect with a photo diode.

When it ages, Rb atoms embeds itself into glass envelope, making it less dense, until the CPT effect is weak enough to be undetectable, then the Rb clock fails.
 
The following users thanked this post: pez

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2221
  • Country: au
  • Country: au
Re: Why are rubidium frequency standards so expensive now?
« Reply #12 on: May 13, 2015, 12:42:39 pm »
There are some articles about how to 'rejuvenate' Rb cells that have deposited the Rb badly.
eg http://www.vk3um.com/Rubidium%20rejuvination.pdf
This is from VK3UM's excellent website this is his page on Rb Clocks alone http://www.vk3um.com/Rubidium%20Standard.html
Whoah! Watch where that landed we might need it later.
 

Offline atferrari

  • Frequent Contributor
  • **
  • Posts: 311
  • Country: ar
  • Country: ar
Re: Why are rubidium frequency standards so expensive now?
« Reply #13 on: May 13, 2015, 12:54:19 pm »
Thanks blueskull and VK5RC for replying.

After reading two hours ago the user manual of one, the mumbo jumbo of information is overwhelming.  :P

The way it is described is a quite convoluted implementation. Wow. :palm:

Agustín Tomás
In theory, there is no difference between theory and practice. In practice, however, there is.
 

Offline bingo600

  • Super Contributor
  • ***
  • Posts: 1358
  • Country: dk
  • Country: dk
Re: Why are rubidium frequency standards so expensive now?
« Reply #14 on: May 16, 2015, 10:11:37 am »
As far as I can tell, there are three units that keep popping up. the Symmetricom SA22c, Stanford Research PRS10, and the FEI model FE5680A.

I pulled up the data sheets for each and Im reading through them but does anyone have any info on which of these are preferable. Im sure a lot of it has to do with the specific user and their needs but are there any general things to watch out for or interesting features available on one but not the others?

Thanks.

I'd chose this way anytime:

1: PRS10         (I actually have one, with 1PPS diciplining)
2: SA22c
..
..
..
X: FE5680      (I actually have 4, and killed the 5'th reversing power  :palm: )

I also have an X72 , quite a nice small unit. But unfortunately w. v4.x firmware so no 1PPS diciplining.

/Bingo
 

Offline pez

  • Contributor
  • Posts: 5
  • Country: at
  • Country: at
Re: Why are rubidium frequency standards so expensive now?
« Reply #15 on: August 15, 2019, 12:03:29 pm »
Why do they have end of life?  Aging of what, actually?  Nothing that you could overcome?

The Rb clocks works as a PLL. The Rb cell resonates at a certain frequency (for CPT clocks, 850.2nm+6.8GHz). At resonant frequency, the transparency of metal vapor goes maximum, therefore, by exciting Rb with such a coherent light source (laser) with 3.4GHz modulated on it, you can observe CPT effect with a photo diode.

When it ages, Rb atoms embeds itself into glass envelope, making it less dense, until the CPT effect is weak enough to be undetectable, then the Rb clock fails.

Hello,

Thank you very much for this most useful explanation!

Well, would you additionally clarify for me at least,
please, if this embedding of the atoms into the glass
also happens when the device is off ?

Sincerely,
 

Offline Bud

  • Super Contributor
  • ***
  • Posts: 3391
  • Country: ca
  • Country: ca
Re: Why are rubidium frequency standards so expensive now?
« Reply #16 on: August 15, 2019, 12:51:56 pm »
It's easier and cheaper to build and GPSDO.

GPSDO has a hassle of requiring an antenna, likely an outside one and longer locking time.
Facebook-free life and Rigol-free shack.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf