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

paul swed paulswedb at gmail.com
Sat Feb 13 02:45:11 UTC 2021 

I see a glass tape on the inner oven with writing "40.0". Thats it.
Assuming C its a long way off.The flask is fine the ovens are heating to
110F. Both of them. So somethings wrong. Interesting as I peel something
like caulking off the outer board I see what looks like a opamp. But its a
FE house number. The top of the can has NSC. The old national semiconductor
label. Could be a LM709 class opamp.

On Fri, Feb 12, 2021 at 9:12 PM Bob kb8tq <kb8tq at n1k.org> wrote:

> 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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