[time-nuts] Austron 1210D Manual Update

[Steve Krull]

Close, but not quite. PMEL is an acronym for Precision Measurement Equipment Laboratory. They are metrology labs tasked with maintenance and operation of the standards for electrical (voltage, current, resistance, frequency, and time) as well as mechanical standards for weight, pressure, etc. Larger labs also had optics and radiation cal facilities. They also calibrated and repaired the working standards and test equipment used by the rest of the base, tenant units, and off-site facilities. I spent 8 years of active duty time, and several more in the ANG, running the time/frequency and RF sections of various PMELs stateside and overseas.
We used the 1210D as a transfer standard to set the timing on everything from comm links to missile launch crypto links. We had a time/frequency console with Cs and Rb standards, as well as HP and Fluke VLF receivers, and a host of HP and Sulzer crystal oscillators, and a fairly sophisticated cross-comparison system. The 1210's were adjusted against the console, driven directly to the silos, and rechecked on return to the lab. The specs for allowable error over the time they were out of the lab are still classified, even though the missile systems are gone. My last couple of years in an air national guard unit, we switched to GPS-disciplined timing standards to set TOD/WOD codes for the secure air-to-air and air-to-ground comm systems. Wish I could remember the manufacturer of the units, Magnavox I think. They were three-piece systems in supposedly EMP-proof boxes, and took three men and a boy to move around.
Steve Krull

---- Brian Kirby <kirbybq at bellsouth.net> wrote:
> PMEL is the correct term in the Air Force. It stands for Precision
> Meteorological Electronic Lab, it the branch of the Air Force that does
> test equipment calibration.
>
> The 1210D was standard test equipment for labs that did not have
> rubidiums and cesiums, which was quite a few.
>
> When I worked in satellite communications back in the late 70s, early
> 80s, I seen a lot of these units (1210D). We used HP cesium beams at
> the earth stations. These units were tracked back the USNO, and we used
> a modem to do time transfer over the air, to check the cesiums drift.
> The cal labs brought there 1210D's to our site about every 30 days to
> calibrate and sync the 1210s.
>
> Rob Kimberley wrote:
> > Hi John,
> >
> > Not heard that one before. It is always possible that there was some batch
> > selection, but unaware of this during my time (July '85 to Dec '88).
> >
> > Rob
> >
> > -----Original Message-----
> > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> > Behalf Of John Ackermann N8UR
> > Sent: 09 March 2007 13:29
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] Austron 1210D Manual Update
> >
> > Rob Kimberley said the following on 03/09/2007 03:25 AM:
> >> John,
> >>
> >> The unit shipped with Austron's 1150 OCXO - a VERY nice oscillator. I
> >> also believe that they sold a bunch of these units to the US Navy for
> >> portable references to sync up Subs.
> >
> > Hi Rob --
> >
> > I had heard mutterings that the 1150s that went into the 1210s weren't quite
> > as hand-picked as the ones that went into the 1250A standard, but this one
> > seems to be doing quite well. (I just got a 1250A that on a quick test
> > performs at least as well as this 1210; I'll be doing a better test after
> > it's had a chance to stabilize for another week or two.)
> >
> > It does appear that an awful lot of the 1210s went into various military
> > applications; one of the few references I found on-line was to one of the
> > PMEL (I think I got that acronym right) chat groups for the Air Force.
> >
> > John
> >
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