[time-nuts] AN/URQ-13 FE-15a oscillator question

Sat Feb 13 02:08:17 UTC 2021

Hi

If you are reading something below 60C on a dewar flask outer oven …. it 
is borken….. very broken.

Bob

> On Feb 12, 2021, at 7:25 PM, paul swed <paulswedb at gmail.com> wrote:
> 
> The temps I am reading are with a K thermocouple so pretty accurate. I had
> simply slid the thermocouple into the flask on the outer edge of the
> ovens.The assembly is out of the flask now and both inner and outer are
> heating. Will see what they do. Both seem to be heating at about the same
> rate. So the great news is the oven windings are not bad. I do see a very
> significant voltage difference on two leads that I might guess matter. But
> still decoding and reverse engineering everything.
> 
> On Fri, Feb 12, 2021 at 5:20 PM Bob kb8tq <kb8tq at n1k.org> wrote:
> 
>> Hi
>> 
>> According to table 1-2 in:
>> 
>> http://www.navy-radio.com/freq/urq-eimb.pdf <
>> http://www.navy-radio.com/freq/urq-eimb.pdf>
>> 
>> The URQ-9 and URQ-10 both were rated for 0 to 50C.
>> 
>> Per:
>> 
>> http://www.navy-radio.com/freq/urq23-MIL-T-28816.pdf <
>> http://www.navy-radio.com/freq/urq23-MIL-T-28816.pdf>
>> 
>> The URQ-23 was rated for 0 to 50C
>> 
>> I’d say it’s a pretty likely that the URQ-13 was rated to operate over
>> 0 to 50C. It went into the same locations and did the same thing as the
>> other devices.
>> 
>> Bob
>> 
>> 
>>> On Feb 12, 2021, at 1:07 PM, paul swed <paulswedb at gmail.com> wrote:
>>> 
>>> Well there is no doubt someone has been deep into this unit. Hint missing
>>> screws internally.
>>> But appears both heater windings are ok.
>>> So inner and outer oven has a new meaning. I typically understood this to
>>> be one oven in another oven. Think the HP CS units of old. The same in
>>> other places HP3801.
>>> But in the URQ13 it means there is a long tube. The Dewar flask. The
>> inner
>>> is deep into the flask and the outer is close to the opening. Two
>>> completely separate heaters. Under the outer heater I will guess is the
>>> actual oscillator for the 5 MHz. Further out from the outer heater are
>> the
>>> offset variable caps thermistor for the outer oven a pot and IC.
>>> Several screws hold this outer heater on and considering the risk of
>> taking
>>> out the remainders to look and draw a schematic.
>>> Regards
>>> Paul
>>> 
>>> On Fri, Feb 12, 2021 at 11:28 AM paul swed <paulswedb at gmail.com> wrote:
>>> 
>>>> Yes Bob they could get hot. But the radio rooms I have been in circa
>> 1970s
>>>> were all air conditioned from destroyers to aircraft carriers. Shirt
>>>> sleeve. The best place to actually be when we were down by the equator
>> was
>>>> the radio room, ET shop, CIC and radar and just maybe the Captain's
>>>> stateroom. But if you were actually there you might still be sweating.
>>>> Chuckle.
>>>> This conversation has given me some good insights. Later today I will
>>>> disable the outer oven. Just curious to see what possible temps might
>> show
>>>> up. Is the inner oven simply reading outer oven leakage. Is there a
>> lead I
>>>> can measure the current of the inner oven....
>>>> Thanks
>>>> 
>>>> On Fri, Feb 12, 2021 at 11:18 AM Bob kb8tq <kb8tq at n1k.org> wrote:
>>>> 
>>>>> Hi
>>>>> 
>>>>> If it’s 105F “outdoors” that’s 40C. Military gear back in the days of
>> the
>>>>> URQ10
>>>>> did not live in air conditioned enclosures. It did get deployed to
>> places
>>>>> with
>>>>> temperatures at or above that level.
>>>>> 
>>>>> If it’s 40C outdoors, by the time you get to a pile of electronics gear
>>>>> *indoors*,
>>>>> a >10C rise is pretty likely. That drives a very common 50C “upper end”
>>>>> temperature
>>>>> on ground gear in relatively benign installations.
>>>>> 
>>>>> This does not just apply to military gear. If you look through test
>>>>> equipment
>>>>> catalogs, a lot of test gear also has the same sort of 50 to 60C upper
>>>>> end spec.
>>>>> The 5065A has a spec of 0 to 50C. The 5061A has the same spec. Both
>>>>> targeted
>>>>> pretty “normal” environments …. ( = they never get below freezing …)
>> and
>>>>> date
>>>>> to the “era” of the URQ10.
>>>>> 
>>>>> In this era of HVAC everywhere, the 5071A has a temp range of 0 to 55C.
>>>>> If
>>>>> anything, this would suggest that things still can get pretty hot.
>>>>> 
>>>>> Bob
>>>>> 
>>>>>> On Feb 12, 2021, at 10:29 AM, paul swed <paulswedb at gmail.com> wrote:
>>>>>> 
>>>>>> Bob
>>>>>> OK there is the math. and that all starts to line up.
>>>>>> So most likely for other URQ units there will be an ambient max in the
>>>>>> spec's. At least on the URQ10 in real life even in the hot tropics the
>>>>>> radio room was shirt sleeve temps.
>>>>>> But the question asked was 110 F correct as measured on the outside of
>>>>> the
>>>>>> outer oven against the dewar flask correct. It isn't. The darn thing
>> is
>>>>>> reasonably stable though.
>>>>>> Since the front panel test switch is not labeled I speculate that the
>>>>>> position for the outer oven is in the normal range. The next switch
>>>>>> position most likely is inner and is not in the correct position. It
>>>>> slowly
>>>>>> moves to the high side.
>>>>>> No real details on anything and a total guess.
>>>>>> Really appreciate the thoughts.
>>>>>> Regards
>>>>>> Paul
>>>>>> WB8TSL
>>>>>> 
>>>>>> On Fri, Feb 12, 2021 at 10:18 AM Bob kb8tq <kb8tq at n1k.org> wrote:
>>>>>> 
>>>>>>> Hi
>>>>>>> 
>>>>>>> Indeed the outer oven (as a minimum) needs to be 5 to 10 C above
>>>>>>> the maximum ambient. If it’s not it goes out of regulation (runs
>> away)
>>>>>>> and you loose any benefit from it. ( = it now works against you ).
>>>>>>> 
>>>>>>> The inner oven as a minimum needs to be 5 to 10 C above the outer
>>>>>>> oven. Again if it is lower, you can / will get into the same runaway
>>>>>>> issue.
>>>>>>> 
>>>>>>> Those offsets are dependent on the way things are insulated. If you
>> are
>>>>>>> using a dewar flask, 5C is probably not going to work for you.
>>>>>>> 
>>>>>>> Your inner oven *also* is impacted by the turn temperature on the
>>>>> crystal
>>>>>>> being used. This *might* have a 20C range. That would put the maximum
>>>>>>> inner oven temperature at 10 + 10 + 20 = 40C above the maximum
>> ambient.
>>>>>>> 
>>>>>>> Needless to say, if the max ambient is 85C, this will get the inner
>>>>> oven
>>>>>>> components up pretty hot. That’s not a real good idea. Derating the
>>>>> heater
>>>>>>> is pretty easy, derating *everything* in there is much more complex.
>>>>> You
>>>>>>> do not often see 85C upper end double ovens ….
>>>>>>> 
>>>>>>> One *could* also ask: “is all this worth it?”. List members *have*
>>>>> written
>>>>>>> papers addressing that point :)
>>>>>>> 
>>>>>>> Bob
>>>>>>> 
>>>>>>>> On Feb 11, 2021, at 10:05 PM, Paul Alfille <paul.alfille at gmail.com>
>>>>>>> wrote:
>>>>>>>> 
>>>>>>>> Shouldn't the outer oven be cooler than the inner oven except during
>>>>>>>> warmup? I would think the inner electronics would be generating
>> heat.
>>>>>>>> 
>>>>>>>> Paul Alfille K1PHA
>>>>>>>> 
>>>>>>>> On Thu, Feb 11, 2021 at 9:30 PM paul swed <paulswedb at gmail.com>
>>>>> wrote:
>>>>>>>> 
>>>>>>>>> 50C is what I have sort of seen over the years. Just wondered could
>>>>>>> there
>>>>>>>>> have been a lower temp version. That made no sense. But then this
>>>>> beast
>>>>>>> has
>>>>>>>>> never made a lot of sense. The $20 mystery from Frequency
>>>>> Electronics.
>>>>>>>>> Thanks Bob
>>>>>>>>> Paul
>>>>>>>>> WB8TSL
>>>>>>>>> 
>>>>>>>>> On Thu, Feb 11, 2021 at 8:08 PM Bob kb8tq <kb8tq at n1k.org> wrote:
>>>>>>>>> 
>>>>>>>>>> Hi
>>>>>>>>>> 
>>>>>>>>>> Even for an outer oven, anything below 60C / 140F would be low
>>>>> enough
>>>>>>> to
>>>>>>>>>> run into significant problems. On a mil device, an upper end
>>>>>>> temperature
>>>>>>>>>> on
>>>>>>>>>> the equipment likely would be over 70C. The outer oven would need
>>>>> to be
>>>>>>>>>> 5 to 10C above that.
>>>>>>>>>> 
>>>>>>>>>> Bob
>>>>>>>>>> 
>>>>>>>>>>> On Feb 11, 2021, at 5:55 PM, paul swed <paulswedb at gmail.com>
>>>>> wrote:
>>>>>>>>>>> 
>>>>>>>>>>> OK I have had several responses and 110F is low as I expected.
>>>>>>>>>>> Wonder if I am being faked out? Perhaps by an inner oven and I am
>>>>> only
>>>>>>>>>>> reading the outside of the outer oven. The Older URQ10 and newer
>>>>> URQ23
>>>>>>>>> do
>>>>>>>>>>> have 2 ovens. The meter switch for test is only labeled 1-9. no
>>>>> other
>>>>>>>>>> clues
>>>>>>>>>>> to the function. I noticed 2 positions change with warm up. Sort
>> of
>>>>>>>>>>> supports the 2 oven theory.
>>>>>>>>>>> Really do not want to take what might be the outer oven off to
>> put
>>>>> the
>>>>>>>>>>> probe in.
>>>>>>>>>>> Thanks everyone.
>>>>>>>>>>> Paul
>>>>>>>>>>> WB8TSL
>>>>>>>>>>> 
>>>>>>>>>>> On Thu, Feb 11, 2021 at 5:32 PM Bob kb8tq <kb8tq at n1k.org> wrote:
>>>>>>>>>>> 
>>>>>>>>>>>> Hi
>>>>>>>>>>>> 
>>>>>>>>>>>> 110 F makes very little sense unless you are in a very cold
>>>>> climate.
>>>>>>>>>>>> For military gear (or any gear for that matter) 43C on the oven
>>>>> just
>>>>>>>>>>>> doesn’t work.
>>>>>>>>>>>> 
>>>>>>>>>>>> 110 C would make sense in a very high temperature environment.
>>>>>>>>>>>> (think of 85C upper end ….).
>>>>>>>>>>>> 
>>>>>>>>>>>> Bob
>>>>>>>>>>>> 
>>>>>>>>>>>>> On Feb 11, 2021, at 2:18 PM, paul swed <paulswedb at gmail.com>
>>>>> wrote:
>>>>>>>>>>>>> 
>>>>>>>>>>>>> Hello to the group.
>>>>>>>>>>>>> I have had a AN/URQ-13 or FE-15a oven oscillator for years.
>>>>>>>>>>>>> Its never worked correctly and in reality some early alpha
>> build.
>>>>>>>>>> (Funny
>>>>>>>>>>>>> that its labeled 15a)
>>>>>>>>>>>>> Looking online there is no documentation that I have been able
>> to
>>>>>>>>> find
>>>>>>>>>>>> over
>>>>>>>>>>>>> the years.
>>>>>>>>>>>>> However in another discussion on a AN/URQ-23 that does have a
>>>>> manual
>>>>>>>>>> and
>>>>>>>>>>>>> schematics I realized my guesses on power could be totally
>> wrong.
>>>>>>>>> Using
>>>>>>>>>>>>> voltages like the URQ23 the URQ13 actually behaves fairly
>> well. I
>>>>>>> was
>>>>>>>>>>>> lucky
>>>>>>>>>>>>> that I didn't destroy something with my original guess.
>>>>>>>>>>>>> That said what I find odd is the internal crystal oven runs at
>>>>>>>>> exactly
>>>>>>>>>>>> 110
>>>>>>>>>>>>> degrees. Its repeatably warms to that level with a range of
>>>>> supply
>>>>>>>>> from
>>>>>>>>>>>> +/-
>>>>>>>>>>>>> 12-15V.
>>>>>>>>>>>>> Does 110 degrees F make any sense at all?
>>>>>>>>>>>>> Thank you
>>>>>>>>>>>>> Paul
>>>>>>>>>>>>> WB8TSL
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>>>>>>>>>>>> 
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