[time-nuts] HP OCXO's 10544A and 10811A
I once bought a groups 8 5370A's.Half had 10811's and half had 10544A's. The 10544A's had lower long term drift than the 10811's. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP OCXO's 10544A and 10811A
Oops, my bad. I think it was a BT cut. But the BT cut isn't any better on warmup than an AT cut, right? I don't know much about the 10544. It was already obsolete by the time I started at HP 40 years ago. Rick N6RK On 8/5/2019 10:20 AM, Scott Newell wrote: At 10:25 AM 8/5/2019, tim...@timeok.it wrote: The 10811 is a SC cut crystal oscillator and the 10544 is an AT cut. I thought the 10544 used a BT rock. Seems like I measured the warmup curve of my 5345A to verify this, but maybe I'm confusing something else. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP OCXO's 10544A and 10811A
At 10:25 AM 8/5/2019, tim...@timeok.it wrote: The 10811 is a SC cut crystal oscillator and the 10544 is an AT cut. I thought the 10544 used a BT rock. Seems like I measured the warmup curve of my 5345A to verify this, but maybe I'm confusing something else. -- newell N5TNL ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP OCXO's 10544A and 10811A
is there a comparison of the key characteristics of these two sub-assembles? The newer 10811 works in older 10544 instruments but not the other way around; the reason is the additional power supply requirements of the 10544. See the data sheets for the 10544 and 10811: http://leapsecond.com/museum/10544/1972-Oct-hp-10544A.pdf http://leapsecond.com/museum/10811a/10811a.pdf Also the 10544 output is spec'd for 1 Vrms into 1000R load; the 10811 is 0.5 V into 50R load. There are differences about warmup time (AT- vs SC-cut). That's important for a often turned-on/off bench instrument; but less important if the oscillator is used as a never-turned-off frequency standard. More info, including data sheets, schematics, and an excellent set of papers by fellow time-nut Charles: http://leapsecond.com/museum/10544/ /tvb ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP OCXO's 10544A and 10811A
Walter, The 10811 uses an SC cut crystal and a more modern oven control circuit. Much better short term stability and warmup than the 10544 it replaced! Cheers, Corby http://www.leapsecond.com/museum/10544/1972-Oct-hp-10544A.pdf http://www.leapsecond.com/museum/10811a/90027-1.pdf ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP OCXO's 10544A and 10811A
On 8/5/2019 7:25 AM, Walter Shawlee 2 wrote: I have hp counters with both OCXO's, they seem to be electrically and mechanically interchangeable, and generally, they both have performed well. but it seems to me that the earlier 10544A runs hotter (to the touch), and is not quite as long term stable as the 10811A. how have they worked for you? is there a comparison of the key characteristics of these two sub-assembles? all the best, walter I worked with the 10811 designers when we were at HP, and I learned as much from them as possible. They were tasked with making an completely new and different oscillator (including a new crystal cut), but with the ability to be able to plug into any legacy 10544 socket. The 10811 famously used the SC cut for fast warm up, vs the AT cut used in the 10544. I remember that the 10811 oven could never draw more current than would be drawn by a 47 ohm resistor. This requirement was derived from the 10544 characteristics. It had to produce 10 MHz at +7 dBm into 50 ohms, etc. Other than the can, the edge card connector, and the location of the tuning screw hole, they started with a blank piece of paper in terms of the oscillator design. There is no similarity between the two ovens. Both oscillators may be offshoots of the Colpitts design, but the 10811 oscillator has various innovations beyond the 10544. It has the patented phase noise reduction circuit, etc. There was no requirement for 10811 sockets to support 10544's. Rick N6RK ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP OCXO's 10544A and 10811A
I have hp counters with both OCXO's, they seem to be electrically and mechanically interchangeable, and generally, they both have performed well. but it seems to me that the earlier 10544A runs hotter (to the touch), and is not quite as long term stable as the 10811A. how have they worked for you? is there a comparison of the key characteristics of these two sub-assembles? all the best, walter -- Walter Shawlee 2 Sphere Research Corp. 3394 Sunnyside Rd. West Kelowna, BC, V1Z 2V4 CANADA Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca +We're all in one boat, no matter how it looks to you. (WS2) +All you need is love. (John Lennon) +But, that doesn't mean other things don't come in handy. (WS2) +Nature is trying very hard to make us succeed, but nature does not depend on us. We are not the only experiment. (R. Buckminster Fuller) ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
