[time-nuts] Quartzlock E10-MRX

Wed Sep 2 00:00:47 UTC 2020

Hi

With an Rb, you have a magnetic shield (somewhere) as part of the overall 
design. In some cases, this is worked into the outer package shell (… it’s 
cheaper to do that way. ). There’s only so much you can do to move the parts
of the unit around.

=====

A fan will not “move” the baseplate any more than a very large passive 
heatsink. To the degree one is slower, it’s due to the very much larger thermal 
mass. In a slowly changing environment ( = typical HVAC system ) there will
be very little difference. 

The key with the fan is to put the $2 into a control circuit. You then have a much
more stable baseplate than you would have with a passive solution. You are not
controlling the entire device surface temperature so it’s not quite the same as 
having it in a fully controlled environment. Even so, it’s probably a significant 
improvement over “out in the open”. 

Bob

> On Sep 1, 2020, at 7:21 PM, Didier Juges <shalimr9 at gmail.com> wrote:
> 
> If you can open the case, you should be able to locate the largest board
> (if there is more than one) where most of the conventional electronics is
> located and devise a way to keep that part of the case cool, with a fan, a
> heatsink or both. The physics package is designed to run hot but if too
> much heat transfers to the electronics, you may run into long term
> reliability problems.
> 
> Hot electronics is relative. My company is involved in high power
> electronics, some of which is used in utility vehicles which still require
> diesel engines for much of their operation. To keep the electronics "cool"
> while eliminating a second liquid cooling system, the trend is to cool the
> electronics with the engine coolant, 105°C... that means in the box
> absolutely nothing is below 105°C. We are talking about converters
> delivering150 kW or more. Like I said, it's all relative...
> 
> Didier KO4BB
> 
> 
> On Tue, Sep 1, 2020, 4:16 PM Taka Kamiya via time-nuts <
> time-nuts at lists.febo.com> wrote:
> 
>> Will you elaborate on fan?  Just about everything I've read, use of fan
>> was discouraged.  Natural convection over heat sink fins were recommended.
>> I've done limited testing.  When fan cooling, indeed temperature will go
>> down, but current consumption stays higher indicating heating is often
>> conducted to keep it hot inside.  How do I reconciliate these opposing
>> conditions in actual use?
>> 
>> ---------------------------------------
>> (Mr.) Taka Kamiya
>> KB4EMF / ex JF2DKG
>> 
>> 
>>    On Tuesday, September 1, 2020, 2:08:04 PM EDT, Bob kb8tq <
>> kb8tq at n1k.org> wrote:
>> 
>> Hi
>> 
>> In this case there may not be much that can be done. In the more general
>> case
>> ( = a unit with a surface that mates to a heatsink) , it’s well worth
>> doing something.
>> 
>> I have an unfortunate lot of empirical evidence (on FRK’s and LPRO’s )
>> showing that
>> a “no heatsink” setup is one with a short life. With no heatsink, a couple
>> of years is
>> doing well on a surplus unit. With a heatsink, > 10 years is quite
>> possible.
>> 
>> How much heatsink? Is the next question. If you can get the baseplate down
>> into the
>> 40’s (C) that’s doing pretty well. A fan plus heatsink may be needed to
>> get this done.
>> If a fan is involved, mag field could become an issue ( = Rb’s are
>> sensitive to mag
>> field, as the fan speed changes the field *may* change).
>> 
>> =====
>> 
>> Indeed this is not always the official word from the Rb manufacturers.
>> I’ve spent
>> considerable effort drinking beer with many of their marketing and
>> engineering
>> guys. The conversation is not *quite* the same when marketing it not at
>> the table.
>> I believe that they simply don’t have a body of long term data “in house”
>> to study.
>> 
>> The fact that I’m not the only one seeing Rb’s die early is backed up on
>> eBay.
>> From time to time, you can find pretty large batches of “for parts” Rb’s.
>> Date codes
>> often are *not* very far back in time.
>> 
>> If they get cheap enough (like ~ $30) they can be fun to play with. You
>> can pretty
>> quickly work out that the electrolytic caps are the most likely failure
>> points. Cap
>> swap outs may only fix 2/3 of them, but it’s quick and easy. You now have
>> a pile
>> of $45 Rb’s ….
>> 
>> Bob
>> 
>> 
>> 
>> 
>>> On Sep 1, 2020, at 9:23 AM, Matthias Welwarsky <time-nuts at welwarsky.de>
>> wrote:
>>> 
>>> On Dienstag, 1. September 2020 14:25:31 CEST Richard Katsch wrote:
>>>> Many thanks Matthias,Hugh.
>>>> 
>>>> The case doesn’t seem to have any direct method of fastening to a
>> heatsink
>>>> but something can be arranged I’m sure. The manufacturer’s documents
>> don’t
>>>> suggest anything. They do say that the base temperature can be up to 85
>>>> degrees C which seems awfully hot.
>>>> 
>>>> I haven’t measured the temperature other than a finger test that
>> indicates
>>>> that more than 5 secs is uncomfortably hot. At that point I switched it
>> off.
>>> 
>>> I wouldn't say "uncomfortably hot" is a cause for alarm. The lamp
>> housing in
>>> the LPRO-101 runs at 100°C, the resonance chamber at roughly the same
>> temp.
>>> You need Rb vapor at around that temperature (if that Rb is a
>> traditional
>>> construction) for the system to work.
>>> 
>>> Anyway, what else can you do? If it's broken, the chances of repairing
>> it are
>>> slim. If it works, no way to find out if it's in spec unless you run it.
>> Just
>>> watch for smoke ;)
>>> 
>>> BR,
>>> Matthias
>>> 
>>>> 
>>>> Best regards
>>>> Richard
>>>> 
>>>> On Tue, 1 Sep 2020 at 19:02, Hugh Blemings <hugh at blemings.org> wrote:
>>>>> Hiya,
>>>>> 
>>>>> 
>>>>> I'd wondered this also - my (limited) experience of Rbs are the
>>>>> 
>>>>> LPROs and they definitely need a heatsink (I have a nice story to
>>>>> 
>>>>> share about getting some made one day which I must write up, but I
>>>>> 
>>>>> digress)
>>>>> 
>>>>> 
>>>>> Curious, I dug around a bit and only data I can find is a two
>>>>> 
>>>>> pager on the manufacturer website -
>>>>> 
>>>>> 
>> https://www.quartzlock.com/product/Rubidium/rubidium-oscillators/E10-MRX
>>>>> 
>>>>> 
>>>>> The packaging itself doesn't appear to be designed with
>>>>> 
>>>>> heatsinking in mind, but perhaps there is an implicit expectation
>>>>> 
>>>>> of convection cooling at least to keep it manageable ?
>>>>> 
>>>>> 
>>>>> Any idea what case temperature you're seeing @Richard ?
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> Cheers,
>>>>> 
>>>>> 
>>>>> Hugh
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> On 1/9/20 5:01 pm, Matthias Welwarsky
>>>>> 
>>>>> wrote:
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> On Dienstag, 1. September 2020 07:15:34 CEST Richard Katsch wrote:
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> Hello All,
>>>>> 
>>>>> I have acquired a Quartzlock E10-MRX Rb 10 MHz standard. It appears to
>>>>> lock
>>>>> 
>>>>> and produce a nice sine wave that stays in phase with my Trimble Tbolt
>> for
>>>>> 
>>>>> a time which exceeds my attention span!!!
>>>>> 
>>>>> It does however get hot in operation. As this is my first experience
>> with
>>>>> a
>>>>> 
>>>>> Rb standard I don’t know whether this is normal or indicates that I
>> need a
>>>>> 
>>>>> heat sink.
>>>>> 
>>>>> Any comments would be appreciated.
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> They're supposed to run hot, but excess temperature will degrade the
>>>>> stability
>>>>> 
>>>>> and shorten the lifetime of the electronics. It's hard to recommend
>> what
>>>>> 
>>>>> heatsink they require if you have no documentation. Typically you'll
>> need
>>>>> one.
>>>>> 
>>>>> My LPRO-101 need a heatsink with < 2K/W of thermal resistance to keep
>> the
>>>>> 
>>>>> temperature in check.
>>>>> 
>>>>> 
>>>>> 
>>>>> BR,
>>>>> 
>>>>> Matthias
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> Regards
>>>>> 
>>>>> Richard Katsch
>>>>> 
>>>>> VK2EIK
>>>>> 
>>>>> _______________________________________________
>>>>> 
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>>>>> the instructions there.
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> _______________________________________________
>>>>> 
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>>> 
>>> 
>>> 
>>> 
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