[time-nuts] Cheap Rubidium (TEC devices)

Bob Camp lists at cq.nu
Sun Dec 27 19:22:50 UTC 2009


Hi

Just in case anybody else is also looking for TEC's:

The eplace has a number of Asian sellers with 100 to 150 W (power not Q) TEC's in the $3.xx to $5.xx range for 10 to 20 pieces delivered to the US. Assuming they are functional, that looks like  better deal than scrapping out brand new gear to get them. 

Of course garage sale acquisitions probably would be the cheaper still.

Bob
On Dec 25, 2009, at 10:58 PM, J. Forster wrote:

> That's a significantly bigger one than I got.
> 
> -John
> 
> =============
> 
> 
>> See:
>> http://www.walgreens.com/store/catalog/Accessories/Kool-Kaddy-12V-Cooler/ID=prod1833617&navCount=0&navAction=push-product
>> <http://www.walgreens.com/store/catalog/Accessories/Kool-Kaddy-12V-Cooler/ID=prod1833617&navCount=0&navAction=push-product>
>> 
>> located using search term:
>> cooler
>> 
>> using the search term
>> thermoelectric
>> is even better
>> 
>> Bruce
>> 
>> Richard W. Solomon wrote:
>>> Can you be a little more specific about the cooler ? Walgreens
>>> search function is rather laborious and clumsy.
>>> 
>>> Tnx, Dick, W1KSZ
>>> 
>>> 
>>> -----Original Message-----
>>> 
>>>> From: "J. Forster"<jfor at quik.com>
>>>> Sent: Dec 24, 2009 6:58 PM
>>>> To: Discussion of precise time and frequency
>>>> measurement<time-nuts at febo.com>
>>>> Subject: Re: [time-nuts] Cheap Rubidium (heatpipe cooling for)
>>>> 
>>>> That's why I've been suggesting active control with TE devices.
>>>> 
>>>> You can buy a small TE cooler at Walgreens for about $20. It's big
>>>> enough
>>>> for a 6-pack of Coke cans and already comes in an insulated box. Add a
>>>> simple temperature control in series w/ the DC supply and you should be
>>>> well on the way.
>>>> 
>>>> -John
>>>> 
>>>> =================
>>>> 
>>>> 
>>>> 
>>>>> Hi
>>>>> 
>>>>> The original intent was to simply take an existing "cheap" rubidium
>>>>> and do
>>>>> simple things to it. Tearing it into pieces and redesigning parts of
>>>>> it
>>>>> was not anything I originally contemplated. The tight integration of
>>>>> the
>>>>> physics package to the electronics would make this a fairly involved
>>>>> process.
>>>>> 
>>>>> Bob
>>>>> 
>>>>> 
>>>>> On Dec 24, 2009, at 5:42 PM, Magnus Danielson wrote:
>>>>> 
>>>>> 
>>>>>> Hal Murray wrote:
>>>>>> 
>>>>>>>> A heat pipe might work if the fluid had a sufficiently low boiling
>>>>>>>> point. The rubidium isn't terribly tolerant of high temperatures,
>>>>>>>> and
>>>>>>>> I'm going to pick up some heat rise as I put it inside some baffles
>>>>>>>> /
>>>>>>>> shields. You need to find something that fits a fairly narrow
>>>>>>>> window.
>>>>>>>> 
>>>>>>> This is all backwards.
>>>>>>> The main reason the typical Rubidium box needs a serious heat sink
>>>>>>> is
>>>>>>> that there is an active heater inside it heating up the lamp to get
>>>>>>> it
>>>>>>> up to operating temperature.  That part of the system better be
>>>>>>> "tolerant" of high (enough) temperature.
>>>>>>> 
>>>>>> ... or a less heat-producing alternative could be used. The
>>>>>> Rubidium-lamp produces two wavelengths of which one is filtered by a
>>>>>> Rubidium-filter which leaves the final pumping wavelength. This is
>>>>>> what
>>>>>> a laser diode could supply instead.
>>>>>> 
>>>>>> 
>>>>>>> Maybe things would be a lot better/simpler if the heating/cooling we
>>>>>>> have been discussing were split into two sections.  One for the lamp
>>>>>>> assembly, and a second for the electronics.
>>>>>>> 
>>>>>> Most of the discussion has been on thermal isolation of the entier
>>>>>> units. Not what needs generates temperature and what requires
>>>>>> temperature stability etc.
>>>>>> 
>>>>>> 
>>>>>>> Anybody know what the thermal coefficient of the lamp is relative to
>>>>>>> the electronics?
>>>>>>> 
>>>>>> I am not sure I know what you mean by this...
>>>>>> 
>>>>>> Cheers,
>>>>>> Magnus
>>>>>> 
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>>>>>> 
>>>>>> 
>>>>> 
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>>>>> 
>>>>> 
>>>> 
>>>> 
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>> 
>> 
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> 
> 
> 
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