mandag den 23. maj 2022 kl. 17.46.31 UTC+2 skrev jla...@highlandsniptechnology.com:
> On Mon, 23 May 2022 14:11:54 -0000 (UTC),
> DecadentLinux...@decadence.org wrote:
>
> >jla...@highlandsniptechnology.com wrote in
> >news:4hjl8hd5d42lhge1c...@4ax.com:
> >
> >> On Sun, 22 May 2022 16:46:44 -0400, bitrex <us...@example.net>
> >> wrote:
> >>
> >>>On 5/22/2022 2:21 PM, jla...@highlandsniptechnology.com wrote:
> >>>> On Sun, 22 May 2022 13:24:02 -0400, bitrex <us...@example.net>
> >>>> wrote:
> >>>>
> >>>>> On 5/22/2022 4:31 AM, Anthony William Sloman wrote:
> >>>>>> On Sunday, May 22, 2022 at 1:15:05 PM UTC+10,
> >>>>>> jla...@highlandsniptechnology.com wrote:
> >>>>>>> On Sat, 21 May 2022 20:50:12 -0400, bitrex
> >>>>>>> <us...@example.net> wrote:
> >>>>>>>
> >>>>>>>> Here's a paper on the theory of crystal ovens:
> >>>>>>>>
> >>>>>>>> <http://www.karlquist.com/oven.pdf>
> >>>>>>
> >>>>>> He didn't survey the literature all that well.
> >>>>>>
> >>>>>>>> There's a lot more to it than just slapping a crystal &
> >>>>>>>> heater in a metal box and calling it a day! There are
> >>>>>>>> probably some pathologically bad geometries even a really
> >>>>>>>> fast control loop can never stabilize very well.
> >>>>>>>>
> >>>>>>>> The part about the outer can acting like a Faraday shield is
> >>>>>>>> interesting, shunting ambient gradients around the core.
> >>>>>>>> Does anyone know how they make the negative space look like
> >>>>>>>> a linear tehrmal resistance over a wide range? There's some
> >>>>>>>> kind of insulating foam in there, is main heat thermal
> >>>>>>>> transfer radiative or conduction?
> >>>>>>
> >>>>>> Conduction. Foam pretty much stops convection.
> >>>>>
> >>>>> It was mentioned on another thread that the thermal resistance
> >>>>> of radiation between two concentric blackbodies at 300K is
> >>>>> about 6mm, interestingly that's very close to the same
> >>>>> thickness of foam-filled negative space between the outer and
> >>>>> inner shells of the OCXO module on my 5334B.
> >>>>>
> >>>>> Don't know if that's a coincidence or not, obviously the two
> >>>>> aren't at exactly 300K. The interior I think runs about 355K,
> >>>>> while the exterior (I haven't measured it) seems cool enough to
> >>>>> keep your hand on a while.
> >>>>>
> >>>>
> >>>> In a reasonably close-fitting box, without a lot of space for
> >>>> convection, air is a better thermal insulator than foam or
> >>>> fiberglass.
> >>>>
> >>>
> >>>Here's a glamour shot of the internals:
> >>>
> >>><https://imgur.com/a/W4hmKt4>
> >>>
> >>>Don't know what the foam is. It doesn't seem to conduct heat too
> >>>good.
> >>>
> >>>
> >>
> >> The interesting test would be to measure heater power with and
> >> without the foam.
> >>
> >>
> >>
> >
> >The foam is for physical shock absorption, silly.
> None of my ovens depended on foam for mechanical support. Sometimes
> long lead wires are bad news too.
>
> I did mount one OCXO on some custom springs. Mating and unmating an
> nearby SMB test connector made my PLL lose lock.
>
> https://www.dropbox.com/s/0k8agdfyiqlwn84/Spring_2.JPG?raw=1
>
> https://www.dropbox.com/s/l2gr4fxas2k05fz/Sprung_Osc_2.JPG?raw=1
> >
> > Hard to protect against that "floating in air". They should try
> >some nice aerogel inserts. I think it has pretty good thermals
> >compared to foam.
> Have you done that? Is aerogel rigid enough to support a subassembly?
> Would mechanical shocks scrunch it down?

https://youtu.be/o5nzYpRdY4g

jlarkin@highlandsniptechnology.com wrote in
news:2gan8hdp7v3lhp44joaa278gmtktgva985@4ax.com:

> On Mon, 23 May 2022 14:11:54 -0000 (UTC),
> DecadentLinuxUserNumeroUno@decadence.org wrote:
>
>>jlarkin@highlandsniptechnology.com wrote in
>>news:4hjl8hd5d42lhge1c7lu0kt7m29led31kd@4ax.com:
>>
>>> On Sun, 22 May 2022 16:46:44 -0400, bitrex <user@example.net>
>>> wrote:
>>>
>>>>On 5/22/2022 2:21 PM, jlarkin@highlandsniptechnology.com wrote:
>>>>> On Sun, 22 May 2022 13:24:02 -0400, bitrex <user@example.net>
>>>>> wrote:
>>>>>
>>>>>> On 5/22/2022 4:31 AM, Anthony William Sloman wrote:
>>>>>>> On Sunday, May 22, 2022 at 1:15:05 PM UTC+10,
>>>>>>> jla...@highlandsniptechnology.com wrote:
>>>>>>>> On Sat, 21 May 2022 20:50:12 -0400, bitrex
>>>>>>>> <us...@example.net> wrote:
>>>>>>>>
>>>>>>>>> Here's a paper on the theory of crystal ovens:
>>>>>>>>>
>>>>>>>>> <http://www.karlquist.com/oven.pdf>
>>>>>>>
>>>>>>> He didn't survey the literature all that well.
>>>>>>>
>>>>>>>>> There's a lot more to it than just slapping a crystal &
>>>>>>>>> heater in a metal box and calling it a day! There are
>>>>>>>>> probably some pathologically bad geometries even a really
>>>>>>>>> fast control loop can never stabilize very well.
>>>>>>>>>
>>>>>>>>> The part about the outer can acting like a Faraday shield
is
>>>>>>>>> interesting, shunting ambient gradients around the core.
>>>>>>>>> Does anyone know how they make the negative space look like
>>>>>>>>> a linear tehrmal resistance over a wide range? There's some
>>>>>>>>> kind of insulating foam in there, is main heat thermal
>>>>>>>>> transfer radiative or conduction?
>>>>>>>
>>>>>>> Conduction. Foam pretty much stops convection.
>>>>>>
>>>>>> It was mentioned on another thread that the thermal resistance
>>>>>> of radiation between two concentric blackbodies at 300K is
>>>>>> about 6mm, interestingly that's very close to the same
>>>>>> thickness of foam-filled negative space between the outer and
>>>>>> inner shells of the OCXO module on my 5334B.
>>>>>>
>>>>>> Don't know if that's a coincidence or not, obviously the two
>>>>>> aren't at exactly 300K. The interior I think runs about 355K,
>>>>>> while the exterior (I haven't measured it) seems cool enough
to
>>>>>> keep your hand on a while.
>>>>>>
>>>>>
>>>>> In a reasonably close-fitting box, without a lot of space for
>>>>> convection, air is a better thermal insulator than foam or
>>>>> fiberglass.
>>>>>
>>>>
>>>>Here's a glamour shot of the internals:
>>>>
>>>><https://imgur.com/a/W4hmKt4>
>>>>
>>>>Don't know what the foam is. It doesn't seem to conduct heat too
>>>>good.
>>>>
>>>>
>>>
>>> The interesting test would be to measure heater power with and
>>> without the foam.
>>>
>>>
>>>
>>
>>The foam is for physical shock absorption, silly.
>
> None of my ovens depended on foam for mechanical support. Sometimes
> long lead wires are bad news too.
>
> I did mount one OCXO on some custom springs. Mating and unmating an
> nearby SMB test connector made my PLL lose lock.
>
> https://www.dropbox.com/s/0k8agdfyiqlwn84/Spring_2.JPG?raw=1
>
> https://www.dropbox.com/s/l2gr4fxas2k05fz/Sprung_Osc_2.JPG?raw=1
>
>
>>
>> Hard to protect against that "floating in air". They should try
>>some nice aerogel inserts. I think it has pretty good thermals
>>compared to foam.
>
> Have you done that? Is aerogel rigid enough to support a
subassembly?
> Would mechanical shocks scrunch it down?
>
The word for today is scrunch.

I don't know. it isn't a foam. so scrunching of any kind would be a
different animal with it. One has to wonder how it reacts to
thermals though.

There were/are several ISS exterior exposure tests taking place.
For micro-meteor impact data and I think there were some thermal
tests.

Someone will make some carbon nanotube matrix thing that beats it
all because we will be able to shape it. Oh wait. that's conduction.
even electrical. They could come up with an idealized resistance
medium and make big high wattage "carbon comp" resistors again for
certain applications. Less noisy than what we used for so many
decades. Or, a nice 'clean' noise... the sound of things going bump
in the night (day too).

Insulation... right. Aerogel. Maybe they make a Hydrogel or
Nitrogel. Or Xenon... apply juice and get a glow gel.

On Monday, May 23, 2022 at 8:46:31 AM UTC-7, jla...@highlandsniptechnology.com wrote:
> On Mon, 23 May 2022 14:11:54 -0000 (UTC),
> DecadentLinux...@decadence.org wrote:

> >The foam is for physical shock absorption, silly.

> None of my ovens depended on foam for mechanical support. Sometimes
> long lead wires are bad news too.
>
> I did mount one OCXO on some custom springs...

> > Hard to protect against that "floating in air". They should try
> >some nice aerogel inserts. I think it has pretty good thermals
> >compared to foam.

> Have you done that? Is aerogel rigid enough to support a subassembly?
> Would mechanical shocks scrunch it down?

Some aerogels are foam-like quartz, quite strong enough for most uses, and
relatively tough. You could use 'em to support, and they're good in vacuum (if
you want a good insulator, ditch the air). On the other hand, a perforated
section of fiberglass PCB should likewise be a thermal break. How
stingy on heater power do you want to be?

John Dope <always.look@message.header> wrote in news:t6gdmo$or8$6@dont-
email.me:

> jlarkin@highlandsniptechnology.com wrote:
>
>> Anybody can count to one.
>>
>> - Robert Widlar
>
> I don't get it.
>
> allintext:"Anybody can count to one" "Robert Widlar"
>
> Produces four results, all of them from John Larkin.
>

Widlar was an engineer, idiot. Consider yourself 'flipped off'.

You have to be a complete idiot to search and not find Widlar info.

Mike Coon wrote:
> In article <t6fga4$f2p$1@dont-email.me>, pNaonStpealmtje@yahoo.com
> says...
>>
>> On a sunny day (Sun, 22 May 2022 22:51:09 +0100) it happened Mike Coon
>> <gravity@mjcoon.plus.com> wrote in
>> <MPG.3cf4c0956a87c90d9896be@usenet.plus.net>:
>>
>>> My design for a foyer quartz clock back in the early 1960s included a
>>> crystal in a thermostatic oven made from Perspex. I have a sketch and
>>> isometric of the oven and a note that there were five thermistors in a
>>> bridge, but no schematic. I do remember that on first testing the
>>> control circuit initially ran at full power heating, then cut off, then
>>> gradually settled on steady warmth!
>>
>> Yes that is overshot, maybe over-compensated
>
> My definition of over-compensated would be indefinite oscillation, which
> is what I was concerned about when I was monitoring the behaviour... No
> theory involved!
>

The usual terminology would be "underdamped" if it's linear, or "windup"
if it isn't.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

On 5/23/2022 11:46 AM, jlarkin@highlandsniptechnology.com wrote:
> On Mon, 23 May 2022 14:11:54 -0000 (UTC),
> DecadentLinuxUserNumeroUno@decadence.org wrote:
>
>> jlarkin@highlandsniptechnology.com wrote in
>> news:4hjl8hd5d42lhge1c7lu0kt7m29led31kd@4ax.com:
>>
>>> On Sun, 22 May 2022 16:46:44 -0400, bitrex <user@example.net>
>>> wrote:
>>>
>>>> On 5/22/2022 2:21 PM, jlarkin@highlandsniptechnology.com wrote:
>>>>> On Sun, 22 May 2022 13:24:02 -0400, bitrex <user@example.net>
>>>>> wrote:
>>>>>
>>>>>> On 5/22/2022 4:31 AM, Anthony William Sloman wrote:
>>>>>>> On Sunday, May 22, 2022 at 1:15:05 PM UTC+10,
>>>>>>> jla...@highlandsniptechnology.com wrote:
>>>>>>>> On Sat, 21 May 2022 20:50:12 -0400, bitrex
>>>>>>>> <us...@example.net> wrote:
>>>>>>>>
>>>>>>>>> Here's a paper on the theory of crystal ovens:
>>>>>>>>>
>>>>>>>>> <http://www.karlquist.com/oven.pdf>
>>>>>>>
>>>>>>> He didn't survey the literature all that well.
>>>>>>>
>>>>>>>>> There's a lot more to it than just slapping a crystal &
>>>>>>>>> heater in a metal box and calling it a day! There are
>>>>>>>>> probably some pathologically bad geometries even a really
>>>>>>>>> fast control loop can never stabilize very well.
>>>>>>>>>
>>>>>>>>> The part about the outer can acting like a Faraday shield is
>>>>>>>>> interesting, shunting ambient gradients around the core.
>>>>>>>>> Does anyone know how they make the negative space look like
>>>>>>>>> a linear tehrmal resistance over a wide range? There's some
>>>>>>>>> kind of insulating foam in there, is main heat thermal
>>>>>>>>> transfer radiative or conduction?
>>>>>>>
>>>>>>> Conduction. Foam pretty much stops convection.
>>>>>>
>>>>>> It was mentioned on another thread that the thermal resistance
>>>>>> of radiation between two concentric blackbodies at 300K is
>>>>>> about 6mm, interestingly that's very close to the same
>>>>>> thickness of foam-filled negative space between the outer and
>>>>>> inner shells of the OCXO module on my 5334B.
>>>>>>
>>>>>> Don't know if that's a coincidence or not, obviously the two
>>>>>> aren't at exactly 300K. The interior I think runs about 355K,
>>>>>> while the exterior (I haven't measured it) seems cool enough to
>>>>>> keep your hand on a while.
>>>>>>
>>>>>
>>>>> In a reasonably close-fitting box, without a lot of space for
>>>>> convection, air is a better thermal insulator than foam or
>>>>> fiberglass.
>>>>>
>>>>
>>>> Here's a glamour shot of the internals:
>>>>
>>>> <https://imgur.com/a/W4hmKt4>
>>>>
>>>> Don't know what the foam is. It doesn't seem to conduct heat too
>>>> good.
>>>>
>>>>
>>>
>>> The interesting test would be to measure heater power with and
>>> without the foam.
>>>
>>>
>>>
>>
>> The foam is for physical shock absorption, silly.
>
> None of my ovens depended on foam for mechanical support. Sometimes
> long lead wires are bad news too.
>
> I did mount one OCXO on some custom springs. Mating and unmating an
> nearby SMB test connector made my PLL lose lock.
>
> https://www.dropbox.com/s/0k8agdfyiqlwn84/Spring_2.JPG?raw=1
>
> https://www.dropbox.com/s/l2gr4fxas2k05fz/Sprung_Osc_2.JPG?raw=1
>
>
>>
>> Hard to protect against that "floating in air". They should try
>> some nice aerogel inserts. I think it has pretty good thermals
>> compared to foam.
>
> Have you done that? Is aerogel rigid enough to support a subassembly?
> Would mechanical shocks scrunch it down?

The foam inside the HP oven is stiff & brittle. I think it may just be
to separate the bits from each other and provide mechanical support, but
I don't think I'd want to rely on it to absorb much shock.

On 5/23/2022 5:40 PM, bitrex wrote:

>>>   Hard to protect against that "floating in air".  They should try
>>> some nice aerogel inserts.  I think it has pretty good thermals
>>> compared to foam.
>>
>> Have you done that? Is aerogel rigid enough to support a subassembly?
>> Would mechanical shocks scrunch it down?
>
> The foam inside the HP oven is stiff & brittle.

Basically the consistency of dehydrated "astronaut" ice cream if you've
had that stuff..

On 5/23/2022 9:48 AM, Phil Hobbs wrote:

>> The interesting test would be to measure heater power with and without
>> the foam.
>
> Air at room temperature has an alpha of about 0.026 W/m/K.  High-density
> styrofoam (the kind that crunches when you poke it with your finger) is
> about 0.040, and low-density styrofoam (the kind that squeaks) is around
> 0.030.
>
> Cheers
>
> Phil Hobbs
>

The way I would describe the "insulating" (or whatever it does) foam in
the HP oven is sort of the consistency of freeze-dried ice cream.

bitrex <user@example.net> wrote in news:QaTiK.4601$8T.2667@fx40.iad:

> On 5/23/2022 11:46 AM, jlarkin@highlandsniptechnology.com wrote:
>> On Mon, 23 May 2022 14:11:54 -0000 (UTC),
>> DecadentLinuxUserNumeroUno@decadence.org wrote:
>>
>>> jlarkin@highlandsniptechnology.com wrote in
>>> news:4hjl8hd5d42lhge1c7lu0kt7m29led31kd@4ax.com:
>>>
>>>> On Sun, 22 May 2022 16:46:44 -0400, bitrex <user@example.net>
>>>> wrote:
>>>>
>>>>> On 5/22/2022 2:21 PM, jlarkin@highlandsniptechnology.com
>>>>> wrote:
>>>>>> On Sun, 22 May 2022 13:24:02 -0400, bitrex <user@example.net>
>>>>>> wrote:
>>>>>>
>>>>>>> On 5/22/2022 4:31 AM, Anthony William Sloman wrote:
>>>>>>>> On Sunday, May 22, 2022 at 1:15:05 PM UTC+10,
>>>>>>>> jla...@highlandsniptechnology.com wrote:
>>>>>>>>> On Sat, 21 May 2022 20:50:12 -0400, bitrex
>>>>>>>>> <us...@example.net> wrote:
>>>>>>>>>
>>>>>>>>>> Here's a paper on the theory of crystal ovens:
>>>>>>>>>>
>>>>>>>>>> <http://www.karlquist.com/oven.pdf>
>>>>>>>>
>>>>>>>> He didn't survey the literature all that well.
>>>>>>>>
>>>>>>>>>> There's a lot more to it than just slapping a crystal &
>>>>>>>>>> heater in a metal box and calling it a day! There are
>>>>>>>>>> probably some pathologically bad geometries even a really
>>>>>>>>>> fast control loop can never stabilize very well.
>>>>>>>>>>
>>>>>>>>>> The part about the outer can acting like a Faraday shield
>>>>>>>>>> is interesting, shunting ambient gradients around the
>>>>>>>>>> core. Does anyone know how they make the negative space
>>>>>>>>>> look like a linear tehrmal resistance over a wide range?
>>>>>>>>>> There's some kind of insulating foam in there, is main
>>>>>>>>>> heat thermal transfer radiative or conduction?
>>>>>>>>
>>>>>>>> Conduction. Foam pretty much stops convection.
>>>>>>>
>>>>>>> It was mentioned on another thread that the thermal
>>>>>>> resistance of radiation between two concentric blackbodies
>>>>>>> at 300K is about 6mm, interestingly that's very close to the
>>>>>>> same thickness of foam-filled negative space between the
>>>>>>> outer and inner shells of the OCXO module on my 5334B.
>>>>>>>
>>>>>>> Don't know if that's a coincidence or not, obviously the two
>>>>>>> aren't at exactly 300K. The interior I think runs about
>>>>>>> 355K, while the exterior (I haven't measured it) seems cool
>>>>>>> enough to keep your hand on a while.
>>>>>>>
>>>>>>
>>>>>> In a reasonably close-fitting box, without a lot of space for
>>>>>> convection, air is a better thermal insulator than foam or
>>>>>> fiberglass.
>>>>>>
>>>>>
>>>>> Here's a glamour shot of the internals:
>>>>>
>>>>> <https://imgur.com/a/W4hmKt4>
>>>>>
>>>>> Don't know what the foam is. It doesn't seem to conduct heat
>>>>> too good.
>>>>>
>>>>>
>>>>
>>>> The interesting test would be to measure heater power with and
>>>> without the foam.
>>>>
>>>>
>>>>
>>>
>>> The foam is for physical shock absorption, silly.
>>
>> None of my ovens depended on foam for mechanical support.
>> Sometimes long lead wires are bad news too.
>>
>> I did mount one OCXO on some custom springs. Mating and unmating
>> an nearby SMB test connector made my PLL lose lock.
>>
>> https://www.dropbox.com/s/0k8agdfyiqlwn84/Spring_2.JPG?raw=1
>>
>> https://www.dropbox.com/s/l2gr4fxas2k05fz/Sprung_Osc_2.JPG?raw=1
>>
>>
>>>
>>> Hard to protect against that "floating in air". They should
>>> try
>>> some nice aerogel inserts. I think it has pretty good thermals
>>> compared to foam.
>>
>> Have you done that? Is aerogel rigid enough to support a
>> subassembly? Would mechanical shocks scrunch it down?
>
> The foam inside the HP oven is stiff & brittle. I think it may
> just be to separate the bits from each other and provide
> mechanical support, but I don't think I'd want to rely on it to
> absorb much shock.
>
>

Compared to being suspended in air, I am sure it wil absorb more.
Just what do you think "mechanical support" is?

On 5/23/2022 6:05 PM, DecadentLinuxUserNumeroUno@decadence.org wrote:
> bitrex <user@example.net> wrote in news:QaTiK.4601$8T.2667@fx40.iad:
>
>> On 5/23/2022 11:46 AM, jlarkin@highlandsniptechnology.com wrote:
>>> On Mon, 23 May 2022 14:11:54 -0000 (UTC),
>>> DecadentLinuxUserNumeroUno@decadence.org wrote:
>>>
>>>> jlarkin@highlandsniptechnology.com wrote in
>>>> news:4hjl8hd5d42lhge1c7lu0kt7m29led31kd@4ax.com:
>>>>
>>>>> On Sun, 22 May 2022 16:46:44 -0400, bitrex <user@example.net>
>>>>> wrote:
>>>>>
>>>>>> On 5/22/2022 2:21 PM, jlarkin@highlandsniptechnology.com
>>>>>> wrote:
>>>>>>> On Sun, 22 May 2022 13:24:02 -0400, bitrex <user@example.net>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> On 5/22/2022 4:31 AM, Anthony William Sloman wrote:
>>>>>>>>> On Sunday, May 22, 2022 at 1:15:05 PM UTC+10,
>>>>>>>>> jla...@highlandsniptechnology.com wrote:
>>>>>>>>>> On Sat, 21 May 2022 20:50:12 -0400, bitrex
>>>>>>>>>> <us...@example.net> wrote:
>>>>>>>>>>
>>>>>>>>>>> Here's a paper on the theory of crystal ovens:
>>>>>>>>>>>
>>>>>>>>>>> <http://www.karlquist.com/oven.pdf>
>>>>>>>>>
>>>>>>>>> He didn't survey the literature all that well.
>>>>>>>>>
>>>>>>>>>>> There's a lot more to it than just slapping a crystal &
>>>>>>>>>>> heater in a metal box and calling it a day! There are
>>>>>>>>>>> probably some pathologically bad geometries even a really
>>>>>>>>>>> fast control loop can never stabilize very well.
>>>>>>>>>>>
>>>>>>>>>>> The part about the outer can acting like a Faraday shield
>>>>>>>>>>> is interesting, shunting ambient gradients around the
>>>>>>>>>>> core. Does anyone know how they make the negative space
>>>>>>>>>>> look like a linear tehrmal resistance over a wide range?
>>>>>>>>>>> There's some kind of insulating foam in there, is main
>>>>>>>>>>> heat thermal transfer radiative or conduction?
>>>>>>>>>
>>>>>>>>> Conduction. Foam pretty much stops convection.
>>>>>>>>
>>>>>>>> It was mentioned on another thread that the thermal
>>>>>>>> resistance of radiation between two concentric blackbodies
>>>>>>>> at 300K is about 6mm, interestingly that's very close to the
>>>>>>>> same thickness of foam-filled negative space between the
>>>>>>>> outer and inner shells of the OCXO module on my 5334B.
>>>>>>>>
>>>>>>>> Don't know if that's a coincidence or not, obviously the two
>>>>>>>> aren't at exactly 300K. The interior I think runs about
>>>>>>>> 355K, while the exterior (I haven't measured it) seems cool
>>>>>>>> enough to keep your hand on a while.
>>>>>>>>
>>>>>>>
>>>>>>> In a reasonably close-fitting box, without a lot of space for
>>>>>>> convection, air is a better thermal insulator than foam or
>>>>>>> fiberglass.
>>>>>>>
>>>>>>
>>>>>> Here's a glamour shot of the internals:
>>>>>>
>>>>>> <https://imgur.com/a/W4hmKt4>
>>>>>>
>>>>>> Don't know what the foam is. It doesn't seem to conduct heat
>>>>>> too good.
>>>>>>
>>>>>>
>>>>>
>>>>> The interesting test would be to measure heater power with and
>>>>> without the foam.
>>>>>
>>>>>
>>>>>
>>>>
>>>> The foam is for physical shock absorption, silly.
>>>
>>> None of my ovens depended on foam for mechanical support.
>>> Sometimes long lead wires are bad news too.
>>>
>>> I did mount one OCXO on some custom springs. Mating and unmating
>>> an nearby SMB test connector made my PLL lose lock.
>>>
>>> https://www.dropbox.com/s/0k8agdfyiqlwn84/Spring_2.JPG?raw=1
>>>
>>> https://www.dropbox.com/s/l2gr4fxas2k05fz/Sprung_Osc_2.JPG?raw=1
>>>
>>>
>>>>
>>>> Hard to protect against that "floating in air". They should
>>>> try
>>>> some nice aerogel inserts. I think it has pretty good thermals
>>>> compared to foam.
>>>
>>> Have you done that? Is aerogel rigid enough to support a
>>> subassembly? Would mechanical shocks scrunch it down?
>>
>> The foam inside the HP oven is stiff & brittle. I think it may
>> just be to separate the bits from each other and provide
>> mechanical support, but I don't think I'd want to rely on it to
>> absorb much shock.
>>
>>
>
> Compared to being suspended in air, I am sure it wil absorb more.
> Just what do you think "mechanical support" is?

Do u require mechanical support:

<https://www.mayoclinic.org/tests-procedures/penis-pump/about/pac-20385225>

On Mon, 23 May 2022 17:41:12 -0400, bitrex <user@example.net> wrote:

>On 5/23/2022 5:40 PM, bitrex wrote:
>
>>>>   Hard to protect against that "floating in air".  They should try
>>>> some nice aerogel inserts.  I think it has pretty good thermals
>>>> compared to foam.
>>>
>>> Have you done that? Is aerogel rigid enough to support a subassembly?
>>> Would mechanical shocks scrunch it down?
>>
>> The foam inside the HP oven is stiff & brittle.
>
>Basically the consistency of dehydrated "astronaut" ice cream if you've
>had that stuff..

Dehydrated ice cream? I'm glad I didn't become an astronaut.

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon

On 5/23/2022 6:54 PM, John Larkin wrote:
> On Mon, 23 May 2022 17:41:12 -0400, bitrex <user@example.net> wrote:
>
>> On 5/23/2022 5:40 PM, bitrex wrote:
>>
>>>>>   Hard to protect against that "floating in air".  They should try
>>>>> some nice aerogel inserts.  I think it has pretty good thermals
>>>>> compared to foam.
>>>>
>>>> Have you done that? Is aerogel rigid enough to support a subassembly?
>>>> Would mechanical shocks scrunch it down?
>>>
>>> The foam inside the HP oven is stiff & brittle.
>>
>> Basically the consistency of dehydrated "astronaut" ice cream if you've
>> had that stuff..
>
> Dehydrated ice cream? I'm glad I didn't become an astronaut.
>

Yeah, freeze-dried. No idea if this stuff was actually used on space
flights or when. My mother used to buy it for me at science museum gift
shops when I was a kid, we didn't have much money but she didn't like to
turn me down for a few souvenirs so long as they were "educational"!

It was sweet at least and most sweet stuff tastes good to an 8 y/o:

<https://youtu.be/gmGDBmeyBIs>

The pull-back racer Space Shuttle toy was another classic gift shop
crowd-pleaser.

<https://www.amazon.com/5-Diecast-Pullback-Space-Shuttle/dp/B003PATHLU/>

On Mon, 23 May 2022 10:09:23 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

>On Monday, May 23, 2022 at 8:46:31 AM UTC-7, jla...@highlandsniptechnology.com wrote:
>> On Mon, 23 May 2022 14:11:54 -0000 (UTC),
>> DecadentLinux...@decadence.org wrote:
>
>> >The foam is for physical shock absorption, silly.
>
>> None of my ovens depended on foam for mechanical support. Sometimes
>> long lead wires are bad news too.
>>
>> I did mount one OCXO on some custom springs...
>
>> > Hard to protect against that "floating in air". They should try
>> >some nice aerogel inserts. I think it has pretty good thermals
>> >compared to foam.
>
>> Have you done that? Is aerogel rigid enough to support a subassembly?
>> Would mechanical shocks scrunch it down?
>
>Some aerogels are foam-like quartz, quite strong enough for most uses, and
>relatively tough. You could use 'em to support, and they're good in vacuum (if
>you want a good insulator, ditch the air). On the other hand, a perforated
>section of fiberglass PCB should likewise be a thermal break. How
>stingy on heater power do you want to be?

Heater power is seldom an issue. Heat loss is bad because it makes an
assembly non-isothermal, so that some bits are not at the same
temperature as the feedback sensor. And the difference will vary with
heater power, namely ambient temp.

--

Anybody can count to one.

- Robert Widlar

On a sunny day (Mon, 23 May 2022 17:34:33 +0100) it happened Mike Coon
<gravity@mjcoon.plus.com> wrote in
<MPG.3cf5c7f82510056d9896bf@usenet.plus.net>:

>In article <t6fga4$f2p$1@dont-email.me>, pNaonStpealmtje@yahoo.com
>says...
>>
>> On a sunny day (Sun, 22 May 2022 22:51:09 +0100) it happened Mike Coon
>> <gravity@mjcoon.plus.com> wrote in
>> <MPG.3cf4c0956a87c90d9896be@usenet.plus.net>:
>>
>> >My design for a foyer quartz clock back in the early 1960s included a
>> >crystal in a thermostatic oven made from Perspex. I have a sketch and
>> >isometric of the oven and a note that there were five thermistors in a
>> >bridge, but no schematic. I do remember that on first testing the
>> >control circuit initially ran at full power heating, then cut off, then
>> >gradually settled on steady warmth!
>>
>> Yes that is overshot, maybe over-compensated
>
>My definition of over-compensated would be indefinite oscillation, which
>is what I was concerned about when I was monitoring the behaviour... No
>theory involved!

http://panteltje.com/pub/under_and_over_compensated_IXIMG_0818.JPG

Bob Widlar was a big engineer.

Now, what is the significance of "Anybody can count to one"?

Seems not to be a famous quote.

--

> John Dope <always.look@message.header> wrote in news:t6gdmo$or8$6@dont-
> email.me:
>
>> jlarkin@highlandsniptechnology.com wrote:
>>
>>> Anybody can count to one.
>>>
>>> - Robert Widlar
>>
>> I don't get it.
>>
>> allintext:"Anybody can count to one" "Robert Widlar"
>>
>> Produces four results, all of them from John Larkin.

In article <t6hrnr$2ac$1@dont-email.me>, pNaonStpealmtje@yahoo.com
says...
>
> On a sunny day (Mon, 23 May 2022 17:34:33 +0100) it happened Mike Coon
> <gravity@mjcoon.plus.com> wrote in
> <MPG.3cf5c7f82510056d9896bf@usenet.plus.net>:
>
> >In article <t6fga4$f2p$1@dont-email.me>, pNaonStpealmtje@yahoo.com
> >says...
> >>
> >> On a sunny day (Sun, 22 May 2022 22:51:09 +0100) it happened Mike Coon
> >> <gravity@mjcoon.plus.com> wrote in
> >> <MPG.3cf4c0956a87c90d9896be@usenet.plus.net>:
> >>
> >> >My design for a foyer quartz clock back in the early 1960s included a
> >> >crystal in a thermostatic oven made from Perspex. I have a sketch and
> >> >isometric of the oven and a note that there were five thermistors in a
> >> >bridge, but no schematic. I do remember that on first testing the
> >> >control circuit initially ran at full power heating, then cut off, then
> >> >gradually settled on steady warmth!
> >>
> >> Yes that is overshot, maybe over-compensated
> >
> >My definition of over-compensated would be indefinite oscillation, which
> >is what I was concerned about when I was monitoring the behaviour... No
> >theory involved!
>
> http://panteltje.com/pub/under_and_over_compensated_IXIMG_0818.JPG

Thanks for that idiosyncratic illustration! You could also have reminded
me of the calculus of feedback theory which I studied for my degree back
in the early 1960s. It was merely the modern (?) terminology I was
querying. "Windup" indeed; that's a gramophone!

On Tue, 24 May 2022 08:41:01 +0100, Mike Coon
<gravity@mjcoon.plus.com> wrote:

>In article <t6hrnr$2ac$1@dont-email.me>, pNaonStpealmtje@yahoo.com
>says...
>>
>> On a sunny day (Mon, 23 May 2022 17:34:33 +0100) it happened Mike Coon
>> <gravity@mjcoon.plus.com> wrote in
>> <MPG.3cf5c7f82510056d9896bf@usenet.plus.net>:
>>
>> >In article <t6fga4$f2p$1@dont-email.me>, pNaonStpealmtje@yahoo.com
>> >says...
>> >>
>> >> On a sunny day (Sun, 22 May 2022 22:51:09 +0100) it happened Mike Coon
>> >> <gravity@mjcoon.plus.com> wrote in
>> >> <MPG.3cf4c0956a87c90d9896be@usenet.plus.net>:
>> >>
>> >> >My design for a foyer quartz clock back in the early 1960s included a
>> >> >crystal in a thermostatic oven made from Perspex. I have a sketch and
>> >> >isometric of the oven and a note that there were five thermistors in a
>> >> >bridge, but no schematic. I do remember that on first testing the
>> >> >control circuit initially ran at full power heating, then cut off, then
>> >> >gradually settled on steady warmth!
>> >>
>> >> Yes that is overshot, maybe over-compensated
>> >
>> >My definition of over-compensated would be indefinite oscillation, which
>> >is what I was concerned about when I was monitoring the behaviour... No
>> >theory involved!
>>
>> http://panteltje.com/pub/under_and_over_compensated_IXIMG_0818.JPG
>
>Thanks for that idiosyncratic illustration! You could also have reminded
>me of the calculus of feedback theory which I studied for my degree back
>in the early 1960s. It was merely the modern (?) terminology I was
>querying. "Windup" indeed; that's a gramophone!

We usually tune thermal loops in the classic linear style, for
critically-damped small signal disturbance. They will typically
overshoot at cold-start powerup because the integrator winds up and
rails. Rob did a lot of fancy math to define the software control
loop; I just Spice things like that.

The oven that I pictured has a 2nd order plant response, about 75
minutes tau for the huge aluminum block and about another 17 for the
platform and e/o modulator inside. Spacers set the second time
constant; aluminum, stainless, or plastic.

One goal was to force minimal thermal gradients along the length of
the Mach-Zender electro-optical modulator.

https://www.dropbox.com/sh/knkoywpv6563mj5/AACy1sLNcyqIO8Eik4NRCC9Da?dl=0

We have lots of heater power available so we can stabilize to
millikelvins in about a half hour.

--

Anybody can count to one.

- Robert Widlar

jlarkin@highlandsniptechnology.com wrote:
> On Tue, 24 May 2022 08:41:01 +0100, Mike Coon
> <gravity@mjcoon.plus.com> wrote:
>
>> In article <t6hrnr$2ac$1@dont-email.me>, pNaonStpealmtje@yahoo.com
>> says...
>>>
>>> On a sunny day (Mon, 23 May 2022 17:34:33 +0100) it happened Mike Coon
>>> <gravity@mjcoon.plus.com> wrote in
>>> <MPG.3cf5c7f82510056d9896bf@usenet.plus.net>:
>>>
>>>> In article <t6fga4$f2p$1@dont-email.me>, pNaonStpealmtje@yahoo.com
>>>> says...
>>>>>
>>>>> On a sunny day (Sun, 22 May 2022 22:51:09 +0100) it happened Mike Coon
>>>>> <gravity@mjcoon.plus.com> wrote in
>>>>> <MPG.3cf4c0956a87c90d9896be@usenet.plus.net>:
>>>>>
>>>>>> My design for a foyer quartz clock back in the early 1960s included a
>>>>>> crystal in a thermostatic oven made from Perspex. I have a sketch and
>>>>>> isometric of the oven and a note that there were five thermistors in a
>>>>>> bridge, but no schematic. I do remember that on first testing the
>>>>>> control circuit initially ran at full power heating, then cut off, then
>>>>>> gradually settled on steady warmth!
>>>>>
>>>>> Yes that is overshot, maybe over-compensated
>>>>
>>>> My definition of over-compensated would be indefinite oscillation, which
>>>> is what I was concerned about when I was monitoring the behaviour... No
>>>> theory involved!
>>>
>>> http://panteltje.com/pub/under_and_over_compensated_IXIMG_0818.JPG
>>
>> Thanks for that idiosyncratic illustration! You could also have reminded
>> me of the calculus of feedback theory which I studied for my degree back
>> in the early 1960s. It was merely the modern (?) terminology I was
>> querying. "Windup" indeed; that's a gramophone!
>
> We usually tune thermal loops in the classic linear style, for
> critically-damped small signal disturbance. They will typically
> overshoot at cold-start powerup because the integrator winds up and
> rails. Rob did a lot of fancy math to define the software control
> loop; I just Spice things like that.
>
> The oven that I pictured has a 2nd order plant response, about 75
> minutes tau for the huge aluminum block and about another 17 for the
> platform and e/o modulator inside. Spacers set the second time
> constant; aluminum, stainless, or plastic.
>
> One goal was to force minimal thermal gradients along the length of
> the Mach-Zender electro-optical modulator.
>
> https://www.dropbox.com/sh/knkoywpv6563mj5/AACy1sLNcyqIO8Eik4NRCC9Da?dl=0
>
> We have lots of heater power available so we can stabilize to
> millikelvins in about a half hour.

One of the less-frequently remarked advantages of thermoelectrics is
that anywhere near room temperature they can have considerably better
forcing resistance than heater-only loops with a given bandwidth.

A heater-only loop gets its negative slewing exclusively from the heat
leak, which of course leaks in both directions, whereas a TEC can pull
as well as push, so a TEC-based loop can be better insulated for the
same control bandwidth and slew rate.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

bitrex <user@example.net> wrote in
news:47UiK.3545$vAW9.2843@fx10.iad:

> On 5/23/2022 6:05 PM, DecadentLinuxUserNumeroUno@decadence.org
> wrote:
>> bitrex <user@example.net> wrote in
>> news:QaTiK.4601$8T.2667@fx40.iad:
>>
>>> On 5/23/2022 11:46 AM, jlarkin@highlandsniptechnology.com wrote:
>>>> On Mon, 23 May 2022 14:11:54 -0000 (UTC),
>>>> DecadentLinuxUserNumeroUno@decadence.org wrote:
>>>>
>>>>> jlarkin@highlandsniptechnology.com wrote in
>>>>> news:4hjl8hd5d42lhge1c7lu0kt7m29led31kd@4ax.com:
>>>>>
>>>>>> On Sun, 22 May 2022 16:46:44 -0400, bitrex <user@example.net>
>>>>>> wrote:
>>>>>>
>>>>>>> On 5/22/2022 2:21 PM, jlarkin@highlandsniptechnology.com
>>>>>>> wrote:
>>>>>>>> On Sun, 22 May 2022 13:24:02 -0400, bitrex
>>>>>>>> <user@example.net> wrote:
>>>>>>>>
>>>>>>>>> On 5/22/2022 4:31 AM, Anthony William Sloman wrote:
>>>>>>>>>> On Sunday, May 22, 2022 at 1:15:05 PM UTC+10,
>>>>>>>>>> jla...@highlandsniptechnology.com wrote:
>>>>>>>>>>> On Sat, 21 May 2022 20:50:12 -0400, bitrex
>>>>>>>>>>> <us...@example.net> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Here's a paper on the theory of crystal ovens:
>>>>>>>>>>>>
>>>>>>>>>>>> <http://www.karlquist.com/oven.pdf>
>>>>>>>>>>
>>>>>>>>>> He didn't survey the literature all that well.
>>>>>>>>>>
>>>>>>>>>>>> There's a lot more to it than just slapping a crystal &
>>>>>>>>>>>> heater in a metal box and calling it a day! There are
>>>>>>>>>>>> probably some pathologically bad geometries even a
>>>>>>>>>>>> really fast control loop can never stabilize very well.
>>>>>>>>>>>>
>>>>>>>>>>>> The part about the outer can acting like a Faraday
>>>>>>>>>>>> shield is interesting, shunting ambient gradients
>>>>>>>>>>>> around the core. Does anyone know how they make the
>>>>>>>>>>>> negative space look like a linear tehrmal resistance
>>>>>>>>>>>> over a wide range? There's some kind of insulating foam
>>>>>>>>>>>> in there, is main heat thermal transfer radiative or
>>>>>>>>>>>> conduction?
>>>>>>>>>>
>>>>>>>>>> Conduction. Foam pretty much stops convection.
>>>>>>>>>
>>>>>>>>> It was mentioned on another thread that the thermal
>>>>>>>>> resistance of radiation between two concentric blackbodies
>>>>>>>>> at 300K is about 6mm, interestingly that's very close to
>>>>>>>>> the same thickness of foam-filled negative space between
>>>>>>>>> the outer and inner shells of the OCXO module on my 5334B.
>>>>>>>>>
>>>>>>>>> Don't know if that's a coincidence or not, obviously the
>>>>>>>>> two aren't at exactly 300K. The interior I think runs
>>>>>>>>> about 355K, while the exterior (I haven't measured it)
>>>>>>>>> seems cool enough to keep your hand on a while.
>>>>>>>>>
>>>>>>>>
>>>>>>>> In a reasonably close-fitting box, without a lot of space
>>>>>>>> for convection, air is a better thermal insulator than foam
>>>>>>>> or fiberglass.
>>>>>>>>
>>>>>>>
>>>>>>> Here's a glamour shot of the internals:
>>>>>>>
>>>>>>> <https://imgur.com/a/W4hmKt4>
>>>>>>>
>>>>>>> Don't know what the foam is. It doesn't seem to conduct heat
>>>>>>> too good.
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> The interesting test would be to measure heater power with
>>>>>> and without the foam.
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> The foam is for physical shock absorption, silly.
>>>>
>>>> None of my ovens depended on foam for mechanical support.
>>>> Sometimes long lead wires are bad news too.
>>>>
>>>> I did mount one OCXO on some custom springs. Mating and
>>>> unmating an nearby SMB test connector made my PLL lose lock.
>>>>
>>>> https://www.dropbox.com/s/0k8agdfyiqlwn84/Spring_2.JPG?raw=1
>>>>
>>>> https://www.dropbox.com/s/l2gr4fxas2k05fz/Sprung_Osc_2.JPG?raw=1
>>>>
>>>>
>>>>>
>>>>> Hard to protect against that "floating in air". They
>>>>> should try
>>>>> some nice aerogel inserts. I think it has pretty good
>>>>> thermals compared to foam.
>>>>
>>>> Have you done that? Is aerogel rigid enough to support a
>>>> subassembly? Would mechanical shocks scrunch it down?
>>>
>>> The foam inside the HP oven is stiff & brittle. I think it may
>>> just be to separate the bits from each other and provide
>>> mechanical support, but I don't think I'd want to rely on it to
>>> absorb much shock.
>>>
>>>
>>
>> Compared to being suspended in air, I am sure it wil absorb more.
>> Just what do you think "mechanical support" is?
>
> Do u require mechanical support:

Look at it. It is smaller than the can it is in. So yes, it
requires mechanical support.

snipped retarded link post.

Real mature, twerp.

John Dope <always.look@message.header> wrote in news:t6hvrj$kq3$3@dont-
email.me:

> Bob Widlar was a big engineer.
>
> Now, what is the significance of "Anybody can count to one"?
>
> Seems not to be a famous quote.
>

John Dope is still in the dark. You never knew electronics and have
been a mere interloper all these years, at best.

The actual quote is "Every idiot can count to one."

So even your google skill sucks. John Dope lives up to his name
every time he posts into SED.

On Tue, 24 May 2022 11:06:16 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>jlarkin@highlandsniptechnology.com wrote:
>> On Tue, 24 May 2022 08:41:01 +0100, Mike Coon
>> <gravity@mjcoon.plus.com> wrote:
>>
>>> In article <t6hrnr$2ac$1@dont-email.me>, pNaonStpealmtje@yahoo.com
>>> says...
>>>>
>>>> On a sunny day (Mon, 23 May 2022 17:34:33 +0100) it happened Mike Coon
>>>> <gravity@mjcoon.plus.com> wrote in
>>>> <MPG.3cf5c7f82510056d9896bf@usenet.plus.net>:
>>>>
>>>>> In article <t6fga4$f2p$1@dont-email.me>, pNaonStpealmtje@yahoo.com
>>>>> says...
>>>>>>
>>>>>> On a sunny day (Sun, 22 May 2022 22:51:09 +0100) it happened Mike Coon
>>>>>> <gravity@mjcoon.plus.com> wrote in
>>>>>> <MPG.3cf4c0956a87c90d9896be@usenet.plus.net>:
>>>>>>
>>>>>>> My design for a foyer quartz clock back in the early 1960s included a
>>>>>>> crystal in a thermostatic oven made from Perspex. I have a sketch and
>>>>>>> isometric of the oven and a note that there were five thermistors in a
>>>>>>> bridge, but no schematic. I do remember that on first testing the
>>>>>>> control circuit initially ran at full power heating, then cut off, then
>>>>>>> gradually settled on steady warmth!
>>>>>>
>>>>>> Yes that is overshot, maybe over-compensated
>>>>>
>>>>> My definition of over-compensated would be indefinite oscillation, which
>>>>> is what I was concerned about when I was monitoring the behaviour... No
>>>>> theory involved!
>>>>
>>>> http://panteltje.com/pub/under_and_over_compensated_IXIMG_0818.JPG
>>>
>>> Thanks for that idiosyncratic illustration! You could also have reminded
>>> me of the calculus of feedback theory which I studied for my degree back
>>> in the early 1960s. It was merely the modern (?) terminology I was
>>> querying. "Windup" indeed; that's a gramophone!
>>
>> We usually tune thermal loops in the classic linear style, for
>> critically-damped small signal disturbance. They will typically
>> overshoot at cold-start powerup because the integrator winds up and
>> rails. Rob did a lot of fancy math to define the software control
>> loop; I just Spice things like that.
>>
>> The oven that I pictured has a 2nd order plant response, about 75
>> minutes tau for the huge aluminum block and about another 17 for the
>> platform and e/o modulator inside. Spacers set the second time
>> constant; aluminum, stainless, or plastic.
>>
>> One goal was to force minimal thermal gradients along the length of
>> the Mach-Zender electro-optical modulator.
>>
>> https://www.dropbox.com/sh/knkoywpv6563mj5/AACy1sLNcyqIO8Eik4NRCC9Da?dl=0
>>
>> We have lots of heater power available so we can stabilize to
>> millikelvins in about a half hour.
>
>One of the less-frequently remarked advantages of thermoelectrics is
>that anywhere near room temperature they can have considerably better
>forcing resistance than heater-only loops with a given bandwidth.
>
>A heater-only loop gets its negative slewing exclusively from the heat
>leak, which of course leaks in both directions, whereas a TEC can pull
>as well as push, so a TEC-based loop can be better insulated for the
>same control bandwidth and slew rate.
>
>Cheers
>
>Phil Hobbs

We only run at 30c, and ambient is very reliably 22. We considered
TECs but that was too complex and expensive. We sure don't want a fan
anywhere close to our optics.

The dpak mosfet heaters are cheap!

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon

Am 24.05.22 um 17:06 schrieb Phil Hobbs:
> jlarkin@highlandsniptechnology.com wrote:
he Mach-Zender electro-optical modulator.
>>
>> https://www.dropbox.com/sh/knkoywpv6563mj5/AACy1sLNcyqIO8Eik4NRCC9Da?dl=0
>>
>> We have lots of heater power available so we can stabilize to
>> millikelvins in about a half hour.
>
> One of the less-frequently remarked advantages of thermoelectrics is
> that anywhere near room temperature they can have considerably better
> forcing resistance than heater-only loops with a given bandwidth.
>
> A heater-only loop gets its negative slewing exclusively from the heat
> leak, which of course leaks in both directions, whereas a TEC can pull
> as well as push, so a TEC-based loop can be better insulated for the
> same control bandwidth and slew rate.

But a TEC has a thermal low-impedance-path from inside to the
outside. That is unwanted and one of the reasons for their bad efficiency.
That means that heat transients on the outside get in
immediately and must be activly regulated away, AFTER they have happened.

Yes, one could insulate the outside of the TEC, but that is somewhat ill?

Cheers, Gerhard

The proper quote helped.

Thanks for doing that work for me, Always Insulting.

DecadentLinuxUserNumeroUno@decadence.org wrote:

> John Dope <always.look@message.header> wrote in news:t6hvrj$kq3$3@dont-
> email.me:
>
>> Bob Widlar was a big engineer.
>>
>> Now, what is the significance of "Anybody can count to one"?
>>
>> Seems not to be a famous quote.
>>
>
> John Dope is still in the dark. You never knew electronics and have
> been a mere interloper all these years, at best.
>
> The actual quote is "Every idiot can count to one."
>
> So even your google skill sucks. John Dope lives up to his name
> every time he posts into SED.
>

tirsdag den 24. maj 2022 kl. 20.35.50 UTC+2 skrev Gerhard Hoffmann:
> Am 24.05.22 um 17:06 schrieb Phil Hobbs:
> > jla...@highlandsniptechnology.com wrote:
> he Mach-Zender electro-optical modulator.
> >>
> >> https://www.dropbox.com/sh/knkoywpv6563mj5/AACy1sLNcyqIO8Eik4NRCC9Da?dl=0
> >>
> >> We have lots of heater power available so we can stabilize to
> >> millikelvins in about a half hour.
> >
> > One of the less-frequently remarked advantages of thermoelectrics is
> > that anywhere near room temperature they can have considerably better
> > forcing resistance than heater-only loops with a given bandwidth.
> >
> > A heater-only loop gets its negative slewing exclusively from the heat
> > leak, which of course leaks in both directions, whereas a TEC can pull
> > as well as push, so a TEC-based loop can be better insulated for the
> > same control bandwidth and slew rate.
> But a TEC has a thermal low-impedance-path from inside to the
> outside. That is unwanted and one of the reasons for their bad efficiency.
> That means that heat transients on the outside get in
> immediately and must be activly regulated away, AFTER they have happened.

and every time you stop cooling the heat you just moved come right back at you

John Dope <always.look@message.header> wrote in news:t6j8sq$61v$3@dont-
email.me:

> The proper quote helped.
>

You are a fucking total retard. ALL that was EVER needed was the
guy's name. So you are dumber than a 5 year old. It does not get
dumber than you John Dope.

Kids know how to use the hardware better than you do and they get
better results too.

Aren't you the total retard trying to power a bicycle with a drill
motor?