Re: [time-nuts] Racal-Dana 1991 w. Option 4C - what is that ?
Hi Tom I seem to remember seeing a 5MHz standard in a triple oven at PO Research in London were I worked in 1961. The crystal was made there and was a 5MHz 3rd overtone and either a plano-convex or double-convex shape, I believe. They had a lens grinding machine for generating the blanks. This was in the days of the use of natural quartz too. Alan G3NYK - Original Message - From: Tom Van Baak t...@leapsecond.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, January 31, 2012 5:41 AM Subject: Re: [time-nuts] Racal-Dana 1991 w. Option 4C - what is that ? What makes 5 MHz more stable than 10 MHz? Why not 2.5 MHz and double twice? Or 1.25 MHz and three doublers? Apparently 2.5 MHz is the most stable of all for reasons not fully understood, but accepted. That's why the early Sulzer oscillators were 2.5 Mc. They doubled them to get 5 MHz. I don't have a reference handy but there are charts and curves in old papers on quartz technology that show a peak in performance (Q?) around 2.5 MHz. Doubling, tripling, or quadupling works too but you get noise at every stage so this is not always a solution. The 2.5 MHz blanks are very large and expensive; I heard that's why the industry moved to 5 and then 10 MHz crystals. Perhaps one of the xtal experts on the list can clarify this for us. See also: Brief History of the Development of Ultra-Precise Oscillators http://www.ieee-uffc.org/main/history.asp?file=norton Fifty Years of Progress in Quartz Crystal Frequency Standards http://www.ieee-uffc.org/main/history.asp?file=frerking /tvb ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
It's a 5Mhz crystal with a frequency doubler at the output. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of cfo Sent: 30 January 2012 17:25 To: time-nuts@febo.com Subject: Re: [time-nuts] Racal-Dana 1991 w. Option 4C - what is that ? On Fri, 20 Jan 2012 09:18:32 -0800, Larry McDavid wrote: I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
Hi It's not all smoke and mirrors. The Q of quartz goes up as frequency goes down. Nobody really debates that. As frequency goes down blank diameter would need to grow to keep everything same / same. Again not much debate. What does get a lot of debate is just how small you can get blank diameter and still get reasonable performance. If people just liked 3 diameter crystal packages. Bob On Jan 31, 2012, at 12:41 AM, Tom Van Baak t...@leapsecond.com wrote: What makes 5 MHz more stable than 10 MHz? Why not 2.5 MHz and double twice? Or 1.25 MHz and three doublers? Apparently 2.5 MHz is the most stable of all for reasons not fully understood, but accepted. That's why the early Sulzer oscillators were 2.5 Mc. They doubled them to get 5 MHz. I don't have a reference handy but there are charts and curves in old papers on quartz technology that show a peak in performance (Q?) around 2.5 MHz. Doubling, tripling, or quadupling works too but you get noise at every stage so this is not always a solution. The 2.5 MHz blanks are very large and expensive; I heard that's why the industry moved to 5 and then 10 MHz crystals. Perhaps one of the xtal experts on the list can clarify this for us. See also: Brief History of the Development of Ultra-Precise Oscillators http://www.ieee-uffc.org/main/history.asp?file=norton Fifty Years of Progress in Quartz Crystal Frequency Standards http://www.ieee-uffc.org/main/history.asp?file=frerking /tvb ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
On Fri, 20 Jan 2012 09:18:32 -0800, Larry McDavid wrote: One does occasionally find Racal 9462 ocxo offered on eBay. Also, one sometimes finds non-operational Racal instruments offered at low price but which to have Option 04E installed. I convinced one seller to remove the Option 04E module (the Racal 9462) and sell just that with much lower shipping cost. There is also what is evidently an older Racal frequency standard module similar in appearance to the 9462 but which has screws attaching the end plate rather than the soldered-can 9462; one of those is seen from time to time on eBay from the UK but I have avoided that. I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. I have found pictures of one claiming it's 5Mhz http://www.jbtech.de/parts/racal_dana/9462.html But i have also received a picture from jaap , with a racal 9492 , where it clearly says its a 10Mhz unit. Can anyone clarify ? I think there was an option that enabled the use of other ocxo values is that why a 5Mhz can be used , in some 1991's ? If i ever decide to get a OCXO , i would like to get the right one. Regards CFO ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
On 1/30/2012 9:24 AM, cfo wrote: I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. It is a 5MHz oven but has a doubler board fitted to it, when fitted to the 1992. I would suggest that if you have a t'bolt then you should use that as an external reference. Dan ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
According to the manual (publication TH62B4 issue 4.10.91) options 04T, 04A, 04B are all 10MHz. No mention of 04c. I vaguely remember hearing that Racal were so satisfied with their 5MHz standards than rather than produce a 10MHz version they simply attached a frequency doubler. I have a 9421 with doubler board attached. John H. On 30 Jan 2012, at 17:24, cfo wrote: On Fri, 20 Jan 2012 09:18:32 -0800, Larry McDavid wrote: One does occasionally find Racal 9462 ocxo offered on eBay. Also, one sometimes finds non-operational Racal instruments offered at low price but which to have Option 04E installed. I convinced one seller to remove the Option 04E module (the Racal 9462) and sell just that with much lower shipping cost. There is also what is evidently an older Racal frequency standard module similar in appearance to the 9462 but which has screws attaching the end plate rather than the soldered-can 9462; one of those is seen from time to time on eBay from the UK but I have avoided that. I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. I have found pictures of one claiming it's 5Mhz http://www.jbtech.de/parts/racal_dana/9462.html But i have also received a picture from jaap , with a racal 9492 , where it clearly says its a 10Mhz unit. Can anyone clarify ? I think there was an option that enabled the use of other ocxo values is that why a 5Mhz can be used , in some 1991's ? If i ever decide to get a OCXO , i would like to get the right one. Regards CFO ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
I checked the documentations I have, the option 4C isn't mentionned, but all the (Internal Reference) options 04x (04A=OCXO, 04B=High Stability OCXO, 04T=TCXO, 04E=High Stability OCXO (?)) are 10 MHz. There is a Reference Frequency Multiplier (Option 10) which allows to use 1, 2, 5 or 10 MHz as an external reference. The parts numbers are: option 04A: 11-1710 (oscillator), assy=9444 option 04B: 11-1711 (oscillator), assy=9423 option 04E: 404386 option 04T: 11-1610 (plate assy) + 19-1208 (oscillator PCB) option 10: 19-1164 Hope that helps, Regards, Jean-Louis Le 30/01/2012 17:24, cfo a écrit : On Fri, 20 Jan 2012 09:18:32 -0800, Larry McDavid wrote: One does occasionally find Racal 9462 ocxo offered on eBay. Also, one sometimes finds non-operational Racal instruments offered at low price but which to have Option 04E installed. I convinced one seller to remove the Option 04E module (the Racal 9462) and sell just that with much lower shipping cost. There is also what is evidently an older Racal frequency standard module similar in appearance to the 9462 but which has screws attaching the end plate rather than the soldered-can 9462; one of those is seen from time to time on eBay from the UK but I have avoided that. I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. I have found pictures of one claiming it's 5Mhz http://www.jbtech.de/parts/racal_dana/9462.html But i have also received a picture from jaap , with a racal 9492 , where it clearly says its a 10Mhz unit. Can anyone clarify ? I think there was an option that enabled the use of other ocxo values is that why a 5Mhz can be used , in some 1991's ? If i ever decide to get a OCXO , i would like to get the right one. Regards CFO ___ 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. -- Jean-Louis Oneto OCA GeoAzur - Avenue Nicolas Copernic - 06130 Grasse - France email: jean-louis.on...@obs-azur.fr phone: (+33)[0]4.93.40.53.80 ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
Thank you everyone. It makes sense now , that Racal might use a 5Mhz w. a freq-doubler. I'll use my Tbolt as a ref , or the FEI-5680A i just got. And keep an eye on E... , for a cheap Opt 4e :-) CFO ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
The Racal 9462 ocxo uses a temperature-controlled 5 MHz crystal oscillator inside a sealed can. On the outside end of the can is a small circuit board that doubles the output frequency to 10 MHz. The ocxo cable comes from this circuit board so the output to the counter is 10 MHz. The Racal 9462 operates on 5 vdc and the cable has only three wires, two of which are provided by a shielded cable for the 10 MHz signal. Depending on the age of the ocxo, this doubler circuit board can be either PTH design or (on later units) SMT design. My understanding is that a 5 MHz crystal is inherently more stable than a 10 MHz crystal so better overall performance is achieved by using a 5 MHz crystal and doubling the output to get 10 MHz. I have pictures of these OCXO if you are interested. The Racal Option 04C is a really, really simple 10 MHz oscillator whose performance is terrible! It is not described in any Racal publication I have found and I think it was offered to customers who bought many counters for use in applications where an external precision 10 MHz source was to be used; the Option 04C allows the counter to operate poorly until connected to an external precision 10 MHz source. Option 04E provides the Racal 9462 and there are other ocxo versions, such as Option 04A, that offer better performance than 04C but not so good as Option 04E. Larry On 1/30/2012 9:24 AM, cfo wrote: On Fri, 20 Jan 2012 09:18:32 -0800, Larry McDavid wrote: One does occasionally find Racal 9462 ocxo offered on eBay. Also, one sometimes finds non-operational Racal instruments offered at low price but which to have Option 04E installed. I convinced one seller to remove the Option 04E module (the Racal 9462) and sell just that with much lower shipping cost. There is also what is evidently an older Racal frequency standard module similar in appearance to the 9462 but which has screws attaching the end plate rather than the soldered-can 9462; one of those is seen from time to time on eBay from the UK but I have avoided that. I have been looking for a Racal 9462 ocxo , for my Racal-Dana 1991 counter. I will prob. use my Tbolt anyway , and save the money. But i'm confused ... Is it a 5 Mhz or a 10 Mhz unit. I have found pictures of one claiming it's 5Mhz http://www.jbtech.de/parts/racal_dana/9462.html But i have also received a picture from jaap , with a racal 9492 , where it clearly says its a 10Mhz unit. Can anyone clarify ? I think there was an option that enabled the use of other ocxo values is that why a 5Mhz can be used , in some 1991's ? If i ever decide to get a OCXO , i would like to get the right one. Regards CFO ___ 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. -- Best wishes, Larry McDavid W6FUB Anaheim, CA (20 miles southeast of Los Angeles, near Disneyland) ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
lmcda...@lmceng.com said: My understanding is that a 5 MHz crystal is inherently more stable than a 10 MHz crystal so better overall performance is achieved by using a 5 MHz crystal and doubling the output to get 10 MHz. What makes 5 MHz more stable than 10 MHz? Why not 2.5 MHz and double twice? Or 1.25 MHz and three doublers? -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
What makes 5 MHz more stable than 10 MHz? Why not 2.5 MHz and double twice? Or 1.25 MHz and three doublers? Apparently 2.5 MHz is the most stable of all for reasons not fully understood, but accepted. That's why the early Sulzer oscillators were 2.5 Mc. They doubled them to get 5 MHz. I don't have a reference handy but there are charts and curves in old papers on quartz technology that show a peak in performance (Q?) around 2.5 MHz. Doubling, tripling, or quadupling works too but you get noise at every stage so this is not always a solution. The 2.5 MHz blanks are very large and expensive; I heard that's why the industry moved to 5 and then 10 MHz crystals. Perhaps one of the xtal experts on the list can clarify this for us. See also: Brief History of the Development of Ultra-Precise Oscillators http://www.ieee-uffc.org/main/history.asp?file=norton Fifty Years of Progress in Quartz Crystal Frequency Standards http://www.ieee-uffc.org/main/history.asp?file=frerking /tvb ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
Hi Nuts I just bought a Racal-Dana 1991 (german eb..) , with options 01 : Inputs in back 4C : Unknown ? , but maybe some OCXO (i hope) 55 : GPIB Does anyone know what option 4C could be ? I hope some super nice OCXO option from USAF , they have bases in .DE CFO (Time nut beginner) ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
On 1/20/2012 6:45 AM, cfo wrote: Hi Nuts I just bought a Racal-Dana 1991 (german eb..) , with options 01 : Inputs in back 4C : Unknown ? , but maybe some OCXO (i hope) 55 : GPIB Does anyone know what option 4C could be ? I hope some super nice OCXO option from USAF , they have bases in .DE Option 4C is not listed in the manual, but presumably it refers to the timebase. You will be able to tell best by looking inside when it arrives. Racal made a lot of different ovens of different qualities as well as TCXOs.All the US military had were the 1300 MHz version 1992 counters with a very good OCXO inside, type 9462, so yours is a civilian one, I'm afraid. dr ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
On Fri, 20 Jan 2012 07:33:59 -0800, Dan Rae wrote: On 1/20/2012 6:45 AM, cfo wrote: Hi Nuts I just bought a Racal-Dana 1991 (german eb..) , with options 01 : Inputs in back 4C : Unknown ? , but maybe some OCXO (i hope) 55 : GPIB Does anyone know what option 4C could be ? I hope some super nice OCXO option from USAF , they have bases in .DE Option 4C is not listed in the manual, but presumably it refers to the timebase. You will be able to tell best by looking inside when it arrives. Racal made a lot of different ovens of different qualities as well as TCXOs.All the US military had were the 1300 MHz version 1992 counters with a very good OCXO inside, type 9462, so yours is a civilian one, I'm afraid. dr Daummm :-) Well thats why i got an extra Tbolt for home , i just need some distribution of the 10Mhz. CFO ___ 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] Racal-Dana 1991 w. Option 4C - what is that ?
Racal Option 04C is not an ocxo. I received a Racal 1999 counter advertised with ovened frequency standard but when I examined the actual part installed, it was a simple modular oscillator, a NDK 23-9134 with only a single adjustment. It was not stable with room temperature and devilish to adjust. I complained to the Hong Kong seller and they sent me a Racal Option 04A module as a replacement, which is oven controlled, but not the Racal High Stability Option 04E. This was a big improvement over the Option 04C (which is not described in any Racal literature I've found) but still showed significant ambient temperature sensitivity and again had only a single adjustment. I have subsequently replaced that with a Racal 9462 ocxo, the ocxo furnished as Option 04E and that has both COARSE and FINE adjustments. I now have a Racal 1992 counter/timer running with Option 04E, measuring 10 MHz from a HP Z3801A GPSDO. My current 15°F overnight room temperature variation causes about 0.003 Hz change in displayed frequency when counted with a 10-second gate period. The FINE frequency adjustment is easy to adjust (with due care) and has no backlash or short-term drift that I've seen. Others have reported click-stops and short-term drift after adjustment but I've not seen that. One does occasionally find Racal 9462 ocxo offered on eBay. Also, one sometimes finds non-operational Racal instruments offered at low price but which to have Option 04E installed. I convinced one seller to remove the Option 04E module (the Racal 9462) and sell just that with much lower shipping cost. There is also what is evidently an older Racal frequency standard module similar in appearance to the 9462 but which has screws attaching the end plate rather than the soldered-can 9462; one of those is seen from time to time on eBay from the UK but I have avoided that. I believe the Option 04C was provided only to get the counter running and that this option was offered as a low-cost solution to users who planned to supply precision 10 MHz input to the rear panel frequency standard connector. The Racal 9462 ocxo is in a hermetic can with glass feed throughs, with the can end cap soldered in place. I don't know what is inside the 9462 as I have not tried to open one. The can is not actually hermetic because the interior is exposed when the adjustment cover screws are removed to adjust the frequency. Those screws have a rubber o-ring in a groove under the head of the screw so when the adjustment cover screws are in place, the interior is well sealed. The ocxo itself actually operates at 5 MHz and there is a small PWB on the end, soldered directly to the feed through pins, that doubles the output frequency to 10 MHz. I've acquired several 9462 ocxo of various age and there are both PTH and SMT versions of the frequency doubler PWB. The Racal Option 04E ocxo, the Racal 9462, seems to work very well for its intended purpose. Is the Racal 9462 ocxo, their Option 04E, actually in a double oven, like the HP 10811? I don't know. If interested, I have pictures of the exterior of these options. There was a Racal Option 04R, a Rb standard, but I've never seen one. All of these options interchange easily within the Racal 199n counters and perhaps other Racal models as well. While there are Racal ocxo that operate on 12 volts, all the ones I've seen operate on only 5 volts and have a single cable to apply power and output 10 MHz. The are very easy to replace. Yes, like everyone else here, I'm working on a FEI FE-5680A. Who can resist that? Larry W6FUB On 1/20/2012 6:45 AM, cfo wrote: Hi Nuts I just bought a Racal-Dana 1991 (german eb..) , with options 01 : Inputs in back 4C : Unknown ? , but maybe some OCXO (i hope) 55 : GPIB Does anyone know what option 4C could be ? I hope some super nice OCXO option from USAF , they have bases in .DE ... -- Best wishes, Larry McDavid W6FUB Anaheim, CA (20 miles southeast of Los Angeles, near Disneyland) ___ 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.
