Re: [time-nuts] quartz / liquid nitrogen

Very true Sent from my iPhone > On Apr 3, 2018, at 7:51 PM, Bob kb8tq wrote: > > Hi > > If the objective is great phase noise far removed from carrier, there’s a > gotcha. > > Let’s say you have a 10 dbm source at room and it’s broadband is at KTB of > -174 + 1db. > That

Re: [time-nuts] quartz / liquid nitrogen

Hi If the objective is great phase noise far removed from carrier, there’s a gotcha. Let’s say you have a 10 dbm source at room and it’s broadband is at KTB of -174 + 1db. That gives you -183 dbc. You cool your oscillator to whatever and KTB goes down to -194. You do a bang up job at that

Re: [time-nuts] quartz / liquid nitrogen

Hi Mark: When Aetech started to make their own Tunnel Diodes there was a problem with the neck breaking. Note they were made by alloying a ball of metal onto a highly doped chip, bonding from the lip of the ceramic package to the ball then on to the opposite lip, then etching the chip away

Re: [time-nuts] quartz / liquid nitrogen

Many years ago, circa 1977, I was moved to try some crude tests on a few semiconductor devices at LN2 temperature (77K). These tests were very crude, involving dunking the parts into the LN2 bath, and many failed outright. Most of the devices tested were in plastic packages. Here are the

Re: [time-nuts] quartz / liquid nitrogen

Hi > On Apr 2, 2018, at 11:18 PM, jimlux wrote: > > On 4/2/18 1:39 PM, Hal Murray wrote: >>> If not Nitrogen, how about dry ice (-109F -78C)? >> Dry ice is relatively easy to get. It wouldn't be hard to try a quick >> experiment. > > > CTE mismatch in packages will be a

[time-nuts] quartz / liquid nitrogen

And you want your semiconductors to be in ceramic/lided packages with the bond wires flapping in free air. Bond wires embedded in epoxy like to break... don't ask how I found this out ;-) ... it brings back bad memories... and makes bad memories... Quantum chips have very

Re: [time-nuts] quartz / liquid nitrogen

On 4/2/18 1:39 PM, Hal Murray wrote: If not Nitrogen, how about dry ice (-109F -78C)? Dry ice is relatively easy to get. It wouldn't be hard to try a quick experiment. CTE mismatch in packages will be a significant problem - you might find that your ICs don't work because bond wires

Re: [time-nuts] quartz / liquid nitrogen

Hi > On Apr 2, 2018, at 5:38 PM, Attila Kinali wrote: > > On Mon, 2 Apr 2018 12:46:26 -0700 > "Tom Van Baak" wrote: > >> Has anyone tried running a quartz oscillator at liquid nitrogen >> temperatures: -196 C (-321F, 77K)? It's probably impractical

Re: [time-nuts] quartz / liquid nitrogen

On Mon, 2 Apr 2018 12:46:26 -0700 "Tom Van Baak" wrote: > Has anyone tried running a quartz oscillator at liquid nitrogen > temperatures: -196 C (-321F, 77K)? It's probably impractical commercially, > but maybe something of value to a time nut. Would that dramatically

Re: [time-nuts] quartz / liquid nitrogen

Hi If you dig back in the FCS archives, you will find papers on “cold” OCXO’s. You also will find papers on cryo cooled quartz. The bottom line appears to be that if you are going to all the trouble of cooling things, sapphire (or other exotic materials) are a better bet. Quick simple

Re: [time-nuts] quartz / liquid nitrogen

Tom: I sense a nice experiment! Dry ice temps can be attained with modest Dewars and thermoelectric fridge devices. PID controller and bob's your uncle. Type K thermocouple modules on epay. With that apparat, a nice set of adev vs temperature possible? Dry ice/acetone or ethyl alcohol

Re: [time-nuts] quartz / liquid nitrogen

Hi Tom: Put the dry ice in acetone to the lowest temp. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Has anyone tried running a quartz oscillator at liquid nitrogen temperatures: -196 C (-321F, 77K)?

Re: [time-nuts] quartz / liquid nitrogen

You also run in to mechanical vibration issues from the cooling system. At the temperatures involved you are looking at something like a Stirling cycle cooler. Here is a good article; https://arxiv.org/pdf/1309.5445.pdf Maintaining a very stable temperature probably has a much greater impact.

Re: [time-nuts] quartz / liquid nitrogen

> If not Nitrogen, how about dry ice (-109F -78C)? Dry ice is relatively easy to get. It wouldn't be hard to try a quick experiment. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] quartz / liquid nitrogen

Is the thermal noise generated in the loss in a quartz resonator a significant part of the overall phase noise picture? I would have not thought so. I'd think that a greater benefit ought to be derived from chilling the other parts in the oscillator, such as the active devices. Unless, of

Re: [time-nuts] quartz / liquid nitrogen

In message <299B45118C9248498D7B4F3AFE72231E@pc52>, "Tom Van Baak" writes: >Has anyone tried running a quartz oscillator at liquid nitrogen >temperatures: -196 C (-321F, 77K)? It's probably impractical >commercially, but maybe something of value to a time nut. Whispering gallery

[time-nuts] quartz / liquid nitrogen

Has anyone tried running a quartz oscillator at liquid nitrogen temperatures: -196 C (-321F, 77K)? It's probably impractical commercially, but maybe something of value to a time nut. Would that dramatically lower temperature improve phase noise & short-term performance? Is there a crystal cut