Re: [time-nuts] [hp_agilent_equipment] Re: Upgrade an HP 5342A microwave frequency counter to have an oven oscillator.
The 5342A counter and the 5345A counters both predate the 10811A and were originally fitted with 10544A oscillators for the option 1 high stability timebase Once the 10811A was released the instruments were fitted with the 10811A as a production change going forward and service replacements were done using 10811A's So in this case there is no need to overthink the oscillator choice for upgrading a 5342A counter. If the 10811A is an edge connector version it will fit and provide better performance than standard TCXO Content by Scott Typos by Siri > On Dec 2, 2014, at 4:53 AM, "Dr. David Kirkby (Kirkby Microwave Ltd)" > wrote: > > On 2 Dec 2014 03:10, "wb6dgn_...@att.net[hp_agilent_equipment]" < > hp_agilent_equipm...@yahoogroups.com> wrote: >> >> Isn't the 10811 a "double oven" oscillator (an oven within an oven)? I > also believe it has anticipator circuitry to predict changes based on > environmental parameters. Or...am I confusing this with another oscillator? > > http://www.leapsecond.com/museum/10811a/10811a.pdf > > Has a data sheet. I believe that there are variants of the 10811A that are > double oven, but not all are. > > The fan is not blowing directly onto the oscillator, as they are on > opposite sides of the case. But they are both at the rear and given the > instrument is only half the width of a 19" rack, maybe it is too close. > > I have not checked this myself, but someone said that the 5342A pre-dates > the 10811A, so if purchased a 5342A new with the high stability > oscillator, one would get another oscillator with a poorer specification. > > The 5342A/10811A combination is one of those things one would have to > test, rather than guess. It would need some careful thought about how to do > a worthwhile experiment. > > Anyway, as far as I am concerned, it is certainly worth while fitting the > 10811A, as even without any equipment other than my eyes, I can see the > last few digits are not constantly changing every second or so. There's a > dramatic improvement in short term stability. I would guess it has 2-3 > orders of magnitude better short term stability, based just at looking at > the display. Actual measurements would quantify the improvement. > > If I can get 100-1000x better performance, for an upgrade that costs less > than 25% of the instrument, that is worthwhile to me. Waiting 6 or so > minutes to get a dramatic improvement in performance is not a big deal. > Keeping it plugged in 24/7, for a bit more performance, is not worthwhile > to me, but others may feel otherwise. > > Dave. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] [hp_agilent_equipment] Re: Upgrade an HP 5342A microwave frequency counter to have an oven oscillator.
Hi One clarification - there are multiple ways you can design an OCXO: 1) You can use an outer oven to improve the temperature stability under normal conditions. 2) You can use a second oven to “help” at the cold end of the range (maybe below -20C) 3) You can simply do a really good single oven. Of the three, number 2 is pretty much useless unless you are outdoors in the winter. Number 3 works because oven design is a bit complicated. Gradients / gain balance / correct gain does all matter. Number 1 works when the gain and set points of both the inner and outer ovens are optimized for best performance. This is done by (possibly multiple) temperature runs and adjustments. To much or to little gain and performance degrades. Wrong set point on either oven and performance degrades. The 10811 “double oven” versions are #2 above. The later Z3815’s have an OCXO from category #3. A 260 or MV89 is an example of category #1. Typically single ovens are doing well at 2x10^-9 over -30 to +70C. A reasonable double oven should be able to do < 2x10^-10 over -30 to +70C. Packing a whole bunch of insulation around a single oven may turn it from 2x10^-9 to 5x10^-9 over -30 to +70C. Optimizing one is not “trivial”. Bob > On Dec 2, 2014, at 4:53 AM, Dr. David Kirkby (Kirkby Microwave Ltd) > wrote: > > On 2 Dec 2014 03:10, "wb6dgn_...@att.net[hp_agilent_equipment]" < > hp_agilent_equipm...@yahoogroups.com> wrote: >> >> Isn't the 10811 a "double oven" oscillator (an oven within an oven)? I > also believe it has anticipator circuitry to predict changes based on > environmental parameters. Or...am I confusing this with another oscillator? > > http://www.leapsecond.com/museum/10811a/10811a.pdf > > Has a data sheet. I believe that there are variants of the 10811A that are > double oven, but not all are. > > The fan is not blowing directly onto the oscillator, as they are on > opposite sides of the case. But they are both at the rear and given the > instrument is only half the width of a 19" rack, maybe it is too close. > > I have not checked this myself, but someone said that the 5342A pre-dates > the 10811A, so if purchased a 5342A new with the high stability > oscillator, one would get another oscillator with a poorer specification. > > The 5342A/10811A combination is one of those things one would have to > test, rather than guess. It would need some careful thought about how to do > a worthwhile experiment. > > Anyway, as far as I am concerned, it is certainly worth while fitting the > 10811A, as even without any equipment other than my eyes, I can see the > last few digits are not constantly changing every second or so. There's a > dramatic improvement in short term stability. I would guess it has 2-3 > orders of magnitude better short term stability, based just at looking at > the display. Actual measurements would quantify the improvement. > > If I can get 100-1000x better performance, for an upgrade that costs less > than 25% of the instrument, that is worthwhile to me. Waiting 6 or so > minutes to get a dramatic improvement in performance is not a big deal. > Keeping it plugged in 24/7, for a bit more performance, is not worthwhile > to me, but others may feel otherwise. > > Dave. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] [hp_agilent_equipment] Re: Upgrade an HP 5342A microwave frequency counter to have an oven oscillator.
On 2 Dec 2014 03:10, "wb6dgn_...@att.net[hp_agilent_equipment]" < hp_agilent_equipm...@yahoogroups.com> wrote: > > Isn't the 10811 a "double oven" oscillator (an oven within an oven)? I also believe it has anticipator circuitry to predict changes based on environmental parameters. Or...am I confusing this with another oscillator? http://www.leapsecond.com/museum/10811a/10811a.pdf Has a data sheet. I believe that there are variants of the 10811A that are double oven, but not all are. The fan is not blowing directly onto the oscillator, as they are on opposite sides of the case. But they are both at the rear and given the instrument is only half the width of a 19" rack, maybe it is too close. I have not checked this myself, but someone said that the 5342A pre-dates the 10811A, so if purchased a 5342A new with the high stability oscillator, one would get another oscillator with a poorer specification. The 5342A/10811A combination is one of those things one would have to test, rather than guess. It would need some careful thought about how to do a worthwhile experiment. Anyway, as far as I am concerned, it is certainly worth while fitting the 10811A, as even without any equipment other than my eyes, I can see the last few digits are not constantly changing every second or so. There's a dramatic improvement in short term stability. I would guess it has 2-3 orders of magnitude better short term stability, based just at looking at the display. Actual measurements would quantify the improvement. If I can get 100-1000x better performance, for an upgrade that costs less than 25% of the instrument, that is worthwhile to me. Waiting 6 or so minutes to get a dramatic improvement in performance is not a big deal. Keeping it plugged in 24/7, for a bit more performance, is not worthwhile to me, but others may feel otherwise. Dave. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] [hp_agilent_equipment] Re: Upgrade an HP 5342A microwave frequency counter to have an oven oscillator.
Hi > On Nov 30, 2014, at 4:28 AM, Dr. David Kirkby (Kirkby Microwave Ltd) > wrote: > > On 30 Nov 2014 05:55, "Orin Eman orin.e...@gmail.com > [hp_agilent_equipment]" wrote: > >> Weren't you looking at the LTE Lite? It should do fine as long as you > can get the antenna well situated (not necessarily outdoors, some of us get > along with having it in an upper floor room). I have one on order. It > will be interesting to compare it with the Thunderbolt. >> >> Orin. > > No I didn't, since I don't have an LTE Lite. > > I will get some sort of GPDSO, but are torn between buying one of these > four, which I ordered in price. All 4 have their advantages and > disadvantages. > > 1) LUCENT/SYMMETRICOM Z3810AS, KS24361 L101/L102 $150 > > 2) LTE Lite. $185. > > 3) HP Z3801A has been upgraded by the Chinese seller to a 58503A. $500 I’d buy that (with free postage) long before I’d buy the next one on the list … > > 4) An original HP 58503A. $700. Consider that only having one of any of these still leaves you in the “is it working or not?” quandary. Some combination of devices that adds up to 3 gives you the ability to triangulate between them and be fairly sure of their current level of performance. Running them all off of one antenna is do-able, if that’s the main in your location. It is in mine. “Is it working?” is probably a different level of concern on a brand new modern device, than on a 15 year old new in box part, than on one that may have been out in the rain for a decade. There’s also the “wear and tear” issue on something that may have 25 years of time on it’s running hours meter. > > BTW, I see what you mean about the postage charge from yixunhk. The Z3801A > upgraded to an 58503A is free postage, but for the 58503A one has to > contact the seller. Price as delivered (and fully set up) is the only price that counts. Some of what’s above still needs antennas and power supplies. Some of them are in nice enclosures. Depending on what you have lying around, setup cost may or may not be impacted by these things. Bob > > Dave > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] [hp_agilent_equipment] Re: Upgrade an HP 5342A microwave frequency counter to have an oven oscillator.
On 30 November 2014 at 15:05, fjdvr...@zonnet.nl [hp_agilent_equipment] wrote: > > Dave, > > I have had a 10811 in the 5342A. Not really a problem. However the thing is > that while your counter is switched off the outside temp of the oven warms > up, no surprise here, but when you switch it on, the outside gets cooler and > takes the ref freq also down due to the fan. So the whole benefit of having > the oven in there to improve the accuracy of the thing is marginal. Its just > a design error to put a fan directly on an OCXO. > > I have taken it out again. I now have it run from my rubidium source, The > counter is way more accurate, and depends no longer on it's warm-up time. > Better invest in a good rubidium for your lab. (Or a GPSDO) > > Fred de Vries, PE1FBO I see what you mean about the fan. But the reading is considerably more stable now the OCXO has been put in, and the TCXO removed. Before I mad that change, the output from a signal generator set to 10 GHz was changing around 1 kHz or so over a time fame of a few seconds. Now it shifted 100 Hz or so over a period of hours. I suspect you are right about the fan being bad near the oscillator, but the oven probably insulates the crystal far more from the effects of temperature change compared to the TCXO. The fairly rapid fluctuations I see before might well be the result of air flow over the TCXO. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] [hp_agilent_equipment] Re: Upgrade an HP 5342A microwave frequency counter to have an oven oscillator.
On 30 Nov 2014 05:55, "Orin Eman orin.e...@gmail.com [hp_agilent_equipment]" wrote: > Weren't you looking at the LTE Lite? It should do fine as long as you can get the antenna well situated (not necessarily outdoors, some of us get along with having it in an upper floor room). I have one on order. It will be interesting to compare it with the Thunderbolt. > > Orin. No I didn't, since I don't have an LTE Lite. I will get some sort of GPDSO, but are torn between buying one of these four, which I ordered in price. All 4 have their advantages and disadvantages. 1) LUCENT/SYMMETRICOM Z3810AS, KS24361 L101/L102 $150 2) LTE Lite. $185. 3) HP Z3801A has been upgraded by the Chinese seller to a 58503A. $500 4) An original HP 58503A. $700. BTW, I see what you mean about the postage charge from yixunhk. The Z3801A upgraded to an 58503A is free postage, but for the 58503A one has to contact the seller. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
