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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> >>>>> 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 <[email protected]> >>> 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 <[email protected]> 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 <[email protected]> >>> 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 <[email protected]> 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 <[email protected]> >>> 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 >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> time-nuts mailing list -- [email protected] >>>>>>>>>>> To unsubscribe, go to >>>>>>>>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>>>>>>>>> and follow the instructions there. >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> time-nuts mailing list -- [email protected] >>>>>>>>>> To unsubscribe, go to >>>>>>>>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>>>>>>>> and follow the instructions there. >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> time-nuts mailing list -- [email protected] >>>>>>>>> To unsubscribe, go to >>>>>>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>>>>>>> and follow the instructions there. >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> time-nuts mailing list -- [email protected] >>>>>>>> To unsubscribe, go to >>>>>>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>>>>>> and follow the instructions there. >>>>>>>> >>>>>>> _______________________________________________ >>>>>>> time-nuts mailing list -- [email protected] >>>>>>> To unsubscribe, go to >>>>>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>>>>> and follow the instructions there. >>>>>>> >>>>>> _______________________________________________ >>>>>> time-nuts mailing list -- [email protected] >>>>>> To unsubscribe, go to >>>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>>>> and follow the instructions there. >>>>> >>>>> >>>>> _______________________________________________ >>>>> time-nuts mailing list -- [email protected] >>>>> To unsubscribe, go to >>>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>>> and follow the instructions there. >>>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- [email protected] >>>> To unsubscribe, go to >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>> and follow the instructions there. >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >>> >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
