Re: [time-nuts] PICTIC II ready-made?
There was also the short lived XPLA2 PZ/XCR3320,3960 (Ph/X) SRAM CPLD family, which had to be configured from an external memory... just another exception which confirms the rule. ftp://ftp.xilinx.com/pub/coolpld/isp/960_conf.pdf The even older intel FLEXlogic, bought by Altera, and rebranded FLASHlogic, with the odd CFB/SRAM architecture, had also internal SRAM/Flash configuration memory. In XAPP440 the power-up configuration transfer of Xilinx CPLDs is very briefly mentioned, and in XAPP388 more details for CR-II are provided. Such often overlooked details cold be sometimes crucial... On 4/28/2012 11:46 PM, Bruce Griffiths wrote: Yes, I should have been more specific. The details about the state machine clock behaviour aren't on the datasheet and were obtained by asking Xilinx. The reason for using CMOS RAM to controll the CPLD interconnections is to reduce the static power consumption well below that possible when using EEPROM cells directly. As long as the state machine clock is turned off during normal operation then it will not be a source of timing jitter. I had intended the post as a warning that chip implementation details not necessarily given on the datasheet can be critical for such applications. Bruce MailLists wrote: I guess you wanted to refer to the old XPLA PZ3k/5k CoolRunner series bought from Philips, renamed XCR3k/5k, and later enhanced to XPLA3/XCR3kXL, not the antique FPGA family XC3k... (C)PLDs don't need an external memory for configuration storing, it's internal. There are also some Lattice, ACTEL, and even Xilinx FPGAs with internal non-volatile configuration memory. On 4/28/2012 3:12 PM, Azelio Boriani wrote: configuration is loaded from EEPROM to RAM on power up For every kind of logic? Even for the simplest XC3000 series (and the Altera equivalent EPM3000 series) small EEPROM CPLD? On Sat, Apr 28, 2012 at 9:04 AM, cfoxne...@luna.dyndns.dk wrote: On Fri, 27 Apr 2012 12:03:20 -0700, Jerry Mulchin wrote: You might want to take a look at the Atmel XMEGA parts. Far more capabilities than the ATMega parts. Watch out . If using an Xmega make sure to select the U ... Usb ones. Most of the non U parts have an errata list longer than the datasheet , and in the analog domain they have serious flaws. But going there (smd only) i'd select an arm instead. 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. ___ 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. ___ 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] Wilkinson TDC
The essentials of a Wikinson TDC can be simplified to the attached circuit which only requires the addition of a zero crossing comparator to monitor the voltage across the capacitor C1. A few refinements to improve the capacitor charging current switching transitions and the addition of an upper voltage clamp together with the use of faster transistors may be useful. Apart from level shifting to drive the npn and pnp longtailed pairs only a 2 bit shift register is required for the synchronisers reducing the number of external (to an FPGA or CPLD) logic packages required. The jitter of the count logic etc., isn't critical and can be implemented in an FPGA or CPLD. With a 100MHz synchroniser and counter clock a resolution of 10ps can be achieved with a 1000:1 ratio between charge and discharge currents. Bruce attachment: WilkinsonTDC.png___ 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] Wilkinson TDC
Do you have an actual circuit? It looks a lot like the old hp5360 counter interpolator. Regards Paul On Sun, Apr 29, 2012 at 3:51 AM, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The essentials of a Wikinson TDC can be simplified to the attached circuit which only requires the addition of a zero crossing comparator to monitor the voltage across the capacitor C1. A few refinements to improve the capacitor charging current switching transitions and the addition of an upper voltage clamp together with the use of faster transistors may be useful. Apart from level shifting to drive the npn and pnp longtailed pairs only a 2 bit shift register is required for the synchronisers reducing the number of external (to an FPGA or CPLD) logic packages required. The jitter of the count logic etc., isn't critical and can be implemented in an FPGA or CPLD. With a 100MHz synchroniser and counter clock a resolution of 10ps can be achieved with a 1000:1 ratio between charge and discharge currents. Bruce ___ 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] Antique Rb Standard - Thanks, Pictures, Parts Request, Question
Hi Magnus, On 4/28/2012 5:37 PM, Magnus Danielson wrote: Hi Ed, On 04/28/2012 08:43 PM, Ed Palmer wrote: First, I'd like to thank Magnus, Joe, Paul, and Ed for taking the time to provide answers, ideas, and challenges to my assumptions. It has all been very helpful. I'm still working on it so I don't have a resolution yet. Happy to help, while not tossing you necessarily the solution, we have to read up and we all learn in the process... which was kind of the point with the exercise. Second, pictures. If anyone is interested, check out http://s701.photobucket.com/albums/ww18/edpalmer42/Tracor%20304-B/ . Nice photos. Thanks. GAS building up. What does GAS mean? Third, I'd like to build an extender board, but I can't find the connectors. The contacts are called Varicon and are used both on circuit boards and in connectors. The connector version is available, but I can't find the board version. The last picture in the above gallery shows a close-up of the connectors. They were available in regular and mini versions. I need the regular ones that stand about 4.3 mm high. The minis are about 3.5 mm high and won't mate with the regular ones. New ones could be loose or spaced out on a plastic strip to make installation easier. Fourth, I'm currently working on the cavity tuning. Does anyone know of a document or research paper that discusses cavity sizes for Rb standards - preferably with equations? I found this document: http://www.alcatel-lucent.com/bstj/vol25-1946/articles/bstj25-3-408.pdf Good article. Thanks for the reference. that talks about cavities in general, but the calculations don't work. I'm guessing that the Rb cell is changing the resonant frequency of the cavity. The glass pulls the cavity resonance somewhat, yes. A TE111 resonance mode is typically used, allowing light to enter and leave at the ends of the cylinder. TE011 was used before, but it much larger. Todays modern cells use a loaded cell (dielectrum added) to move the resonance frequency down, which allows much smaller physical cells. This unit is TE011 No dielectric, plain brass - not silver-plated, 2.495 inch diameter @ room temperature, length tunable from ~0.9 to 1.07 inches. W.J.Riley Rubidium Frequency Standard Primer is a good starting-point, but following the references should help. I think just searching for TE111 mode rubidium cranks out a few interesting things, such as: http://dspace.thapar.edu:8080/dspace/bitstream/10266/968/1/Satyendr_Thesis.pdf Thanks for that link. I have been searching, but it's like panning for gold - lots of sand and dirt and a very few nuggets of gold. Ed Cheers, Magnus ___ 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] Antique Rb Standard - Thanks, Pictures, Parts
Hi Gordon, I checked the link. The contacts are the same family, but they're a smaller version for use in connectors rather than soldered into a board. Thanks, Ed On 4/28/2012 6:05 PM, Gordon Batey wrote: Greetings to the time keepers, We used to use those connectors way back in the dark ages in GE Numerical Controlled machine tool controls to connect daughter boards to the mother board as I recall. It is a bifurcated (?) connector and We called them ELCO connectors. Check out: http://www.edac-elcoconnectors.com/ the solder eye pin near the bottom of the page might be close *Edac #* *516-290-500* Hope that this helps. Gordon WA4FJC ___ 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] Trimble Thunderbolt GPS Antenna
Hi, Time-Nuts guys I just baught a Trimble Thunderbolt on ebay. I am in need of an antenna, there are so many on ebay I am not sure which one to get. Maybe someone could point me in the right direction? Thankyou Ken Kubick kenkub...@hotmail.com ___ 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] Trimble Thunderbolt GPS Antenna
I've been pleased with the performance of the Symmetricom 58532. I believe it has more gain than many other antennas and my case feeds a lengthy run (maybe 80 feet or so ?) of RG58 whichin turn feeds my Thunderbolt. --- On Sun, 4/29/12, Ken Kubick kenkub...@hotmail.com wrote: From: Ken Kubick kenkub...@hotmail.com Subject: [time-nuts] Trimble Thunderbolt GPS Antenna To: Time Nuts time-nuts@febo.com Received: Sunday, April 29, 2012, 12:29 PM Hi, Time-Nuts guys I just baught a Trimble Thunderbolt on ebay. I am in need of an antenna, there are so many on ebay I am not sure which one to get. Maybe someone could point me in the right direction? Thankyou Ken Kubick kenkub...@hotmail.com ___ 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] Trimble Thunderbolt GPS Antenna
Hi Ken, Hi, Time-Nuts guys I just baught a Trimble Thunderbolt on ebay. I am in need of an antenna, there are so many on ebay I am not sure which one to get. Maybe someone could point me in the right direction? Thankyou Ken Kubick How long antenna cable do you need in your location? How low-loss antenna cable will you use? The orginal antenna to the Tbolt is the Trimble Bullet antenna. http://trl.trimble.com/docushare/dsweb/Get/Document-8420/Bullet-III_DS.pdf Ebay #220997989191 Here is a former HP/Agilent antenna that has worked fine for me. http://www.symmetricom.com/products/gps-solutions/gps-timing-products-and-accessories/58532A-GPS-L1-Reference-Antenna/ Generally most GPS antennas will work. (Searching for GPS timing antenna will give you some choice) Here is a very nice antenna. Rather good gain at 33dB, LNA power from 2.5VDC to 24VDC - which means it can take the oldtimer GPS receivers giving 12V or 15V and new giving 3.3V or lower. (Like Antcom antennas, no dealings with that particular seller.) Ebay #150753929036 Datasheet http://antcom.com/productsheets/2G15A-XTB-1-N_D.pdf Good luck! -- Björn ___ 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] Trimble Thunderbolt GPS Antenna
Just about anything will work. The most important thing, more important than the type of antenna is LOCATION. If you have a clear view of the sky and can mount the antenna on a 3/4 galvanized iron pipe mast then the in-expensive pointy 26dB ant. works well (180518378555) These will mount on an iron pipe flange. Some flanges even have the holes in the right location and then you lead the coax down the center of the pipe and everything is 100% weather proof. You should ground the pipe and maybe think about lightening too. I like N type connectors for outdoors. They are water tight and resist corrosion for decades especially if the connector is inside a waterproof pipe. I glued some automotive gasket material to the pipe flange and used stainless bolts. My experience is that such a setup will last forever. I think the N type is worth it for a permanent outdoor installation even if it does require a more expensive coax cable. That said, even a cheap patch antenna works. The t-bolt cares more about what it can see than about gain. Also good to be away from reflections that can cause multi path. That is why I like the pipe mast. It place the antenna is free air. You can strap it to a vent pipe on the roof. I like the pointy top design too. Keeps birds and bird poop off the radome. Snow is not a problem here but if it is at your location the pointy top helps with that too. More gain might be nice if you are looking through a window, trees or whatever. But gain is not a substitute for location. On Sun, Apr 29, 2012 at 9:29 AM, Ken Kubick kenkub...@hotmail.com wrote: 180518378555 Hi, Time-Nuts guys I just baught a Trimble Thunderbolt on ebay. I am in need of an antenna, there are so many on ebay I am not sure which one to get. Maybe someone could point me in the right direction? Thankyou Ken Kubick kenkub...@hotmail.com ___ 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. -- Chris Albertson Redondo Beach, California ___ 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] General Technology Corp model 304b
After following Ed Palmer's thread on 304b restoration,I was inspired to get my GTC (tracor) 304b ser#279 going. It seems that the failure of this unit was the break down of the foam that was wrapped around the vcxo located inside the control box. The vapors or the moisture the foam collected corroded the steel fasteners and caused the switches to become intermittent. The replacement of the foam in the control box is not that much of a problem,what I need help with is what to use around the Rb lamp base. The foam has turned to powder. Should I try Home foam sealant? The cell's ,of this seem about the same as the old foam.Will it take the heat? Should I make a fiberglass cocoon to put around the lamp base. The unit now achieves lock in about an hour. The only other thing I did was to replace the caps in the main supply. Any thoughts on the insulation? Don H ___ 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] Trimble Thunderbolt GPS Antenna
I recently installed one of the 58532A GPS antennas (this same part number is applied to both units marked Symmetricom and marked HP and the data sheets are very similar, though not identical). I'm confident it is the same antenna as the dimensions and appearance are identical. I'm using this with a HP Z3801A and GPSCon software. Previously, I had a simple GPS puck antenna fed with RG-174 and RG-58A. The new HP (that's how mine was supplied new and boxed) antenna uses Andrew 1/2-inch Heliax 50 feet long. Both antennas are in the same rooftop location and have clear field of view. Terminating Andrew Heliax was a learning experience! You *really* want the simple, inexpensive Andrew tool to cut the shield; else, it's hacksaw time... GPSCon reported satellite signal strengths of about 25-80 units with the old antenna and feedline; I did not realize how low was that signal strength until I put up the new antenna. GPSCon now reports signal strengths of about 80-230 units. The new antenna resulted in a marked increase in the average number of satellites tracked. Previously, the plot was a heavy line showing many changes from six to two. With the new antenna, the plot line is typically fixed at six with an occasional drop to 5. HP SmartClock in the Z3801A is slow to react to changes--long filter time constants. But, after about a week, there was significant improvement in the Predicted Uncertainty and in the TI noise average shown in GPSCon. Granted, mine was a big change in antenna and feedline. But, antennas matter! Larry On 4/29/2012 9:51 AM, b...@lysator.liu.se wrote: Hi Ken, Hi, Time-Nuts guys I just baught a Trimble Thunderbolt on ebay. I am in need of an antenna, there are so many on ebay I am not sure which one to get. Maybe someone could point me in the right direction? Thankyou Ken Kubick How long antenna cable do you need in your location? How low-loss antenna cable will you use? The orginal antenna to the Tbolt is the Trimble Bullet antenna. http://trl.trimble.com/docushare/dsweb/Get/Document-8420/Bullet-III_DS.pdf Ebay #220997989191 Here is a former HP/Agilent antenna that has worked fine for me. http://www.symmetricom.com/products/gps-solutions/gps-timing-products-and-accessories/58532A-GPS-L1-Reference-Antenna/ Generally most GPS antennas will work. (Searching for GPS timing antenna will give you some choice) Here is a very nice antenna. Rather good gain at 33dB, LNA power from 2.5VDC to 24VDC - which means it can take the oldtimer GPS receivers giving 12V or 15V and new giving 3.3V or lower. (Like Antcom antennas, no dealings with that particular seller.) Ebay #150753929036 Datasheet http://antcom.com/productsheets/2G15A-XTB-1-N_D.pdf -- 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.
[time-nuts] Fwd: Ocean Optics HR 2000's for sale
Hi, I received the email below and am passing it on for those who might be intertested. Please contact Roland directly, off-list, with any questions, etc. Best, -John = Used Ocean Optics HR2000 Spectrometer, H9 grating (~200 nm bandwidth,) calibrated for ~470 to 670 nm, 10 micron entrance slit. Purchase includes 12 200 micron fiber. One CDROM with Manual and useful Utilities included per purchase. Current pricing for shipment within the continental US, good from April 1, 2012 till June 30, 2012. Hawaii, Canada, and International shipments are individually calculated. Qty Total USPS Priority Mail Shipment to continental US 1 $140 1 box (~2.2 lbs), $200 insurance 2 $260 1 box (~4.4 lbs), $300 insurance 3 $380 1 box (~6.6 lbs), $400 insurance 4 $500 1 box (~8.8 lbs), $500 insurance 5 $640 2 boxes (~11.0 lbs), $700 total insurance 6 $760 2 boxes (~13.2 lbs), $800 total insurance 7 $880 2 boxes (~15.4 lbs), $900 total insurance 8 $1,000 2 boxes (~17.6 lbs), $1,000 total insurance Payable as Cash, Money Order, Certified Check, or Personal Check (shipment after checks clears.) I will consider Paypal for International customers ONLY. There is an additional 5% surcharge for these purchase to cover the additional Paypal costs to me. Email: roland.guil...@yahoo.com for more information. I have a Word document with further information. ___ 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] Fwd: Ocean Optics HR 2000's for sale
These are so neat I bought two of them. Do you Really wanna see what your Rb is doing :-)? Don J. Forster Hi, I received the email below and am passing it on for those who might be intertested. Please contact Roland directly, off-list, with any questions, etc. Best, -John = Used Ocean Optics HR2000 Spectrometer, H9 grating (~200 nm bandwidth,) calibrated for ~470 to 670 nm, 10 micron entrance slit. Purchase includes 12 200 micron fiber. One CDROM with Manual and useful Utilities included per purchase. Current pricing for shipment within the continental US, good from April 1, 2012 till June 30, 2012. Hawaii, Canada, and International shipments are individually calculated. Qty Total USPS Priority Mail Shipment to continental US 1 $140 1 box (~2.2 lbs), $200 insurance 2 $260 1 box (~4.4 lbs), $300 insurance 3 $380 1 box (~6.6 lbs), $400 insurance 4 $500 1 box (~8.8 lbs), $500 insurance 5 $640 2 boxes (~11.0 lbs), $700 total insurance 6 $760 2 boxes (~13.2 lbs), $800 total insurance 7 $880 2 boxes (~15.4 lbs), $900 total insurance 8 $1,000 2 boxes (~17.6 lbs), $1,000 total insurance Payable as Cash, Money Order, Certified Check, or Personal Check (shipment after checks clears.) I will consider Paypal for International customers ONLY. There is an additional 5% surcharge for these purchase to cover the additional Paypal costs to me. Email: roland.guil...@yahoo.com for more information. I have a Word document with further information. ___ 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. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ 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] General Technology Corp model 304b
Try a bit of the spray foam not actually in the unit. Since its intended for houses it should be high temp. Also recall it expands so truly a bit will do. Can't think of other foam. But I would go to a home depot and look at what that have for pipes. It may stand up to the heat. Then cut and fit as needed. Regards Paul. On Sun, Apr 29, 2012 at 1:16 PM, Donald Henderickx wa9...@sandprairie.netwrote: After following Ed Palmer's thread on 304b restoration,I was inspired to get my GTC (tracor) 304b ser#279 going. It seems that the failure of this unit was the break down of the foam that was wrapped around the vcxo located inside the control box. The vapors or the moisture the foam collected corroded the steel fasteners and caused the switches to become intermittent. The replacement of the foam in the control box is not that much of a problem,what I need help with is what to use around the Rb lamp base. The foam has turned to powder. Should I try Home foam sealant? The cell's ,of this seem about the same as the old foam.Will it take the heat? Should I make a fiberglass cocoon to put around the lamp base. The unit now achieves lock in about an hour. The only other thing I did was to replace the caps in the main supply. Any thoughts on the insulation? Don H __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] Antique Rb Standard - Thanks, Pictures, Parts Request, Question
Yes, very nice pictures. That thing is really built and looks like it should be easy to work on and experiment with. I still have to say that I doubt the cavity is off-tune unless something serious happened to it mechanically. Is it even adjustable? If so, maybe someone previously tried to adjust it and messed up. If not, or it appears original, then I think any mistuning will be in the multiplier instead. You can sweep the cavity by placing coupling loops in there, and then see what happens as you go say +/- 100 MHz around the desired center, and then at narrower sweeps. You should get an observable peak at or near the right frequency, and it should be broad enough to include the ideal Rb frequency. When the excitation lamp is on and the cell has some light going through, there should be some absorption, and the cavity Q may decrease a bit, but I doubt it will have much effect. You can try this by sweeping with everything off, and then with the lamp on to see if it's noticeable. Also, as someone else mentioned, it's good to see fully-utilized bench space in the background - plenty of stuff everywhere, at your fingertips. I especially liked the open-sided desktop PC. All of my garage PCs are just like that (I don't even know if I can find the covers) - it gives better cooling, is easy to modify and experiment with, and provides some handy storage space that otherwise would be wasted. Ed ___ 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] General Technology Corp model 304b
Hi Don, You know that we're going to be swapping many emails, don't you? :-) On 4/29/2012 11:16 AM, Donald Henderickx wrote: After following Ed Palmer's thread on 304b restoration,I was inspired to get my GTC (tracor) 304b ser#279 going. It seems that the failure of this unit was the break down of the foam that was wrapped around the vcxo located inside the control box. The vapors or the moisture the foam collected corroded the steel fasteners and caused the switches to become intermittent. The foam around my OCXO is still in great shape. Still spongy and providing lots of holding force for the OCXO. My unit is serial #449. The replacement of the foam in the control box is not that much of a problem,what I need help with is what to use around the Rb lamp base. The foam has turned to powder. Do you mean foam around the back end of the lamp where the wire lead comes out or the foam that surrounds the reflector (#16 in the picture in the patent that describes the lamp (3311775))? My #16 foam is really solid. Should I try Home foam sealant? The cell's ,of this seem about the same as the old foam.Will it take the heat?Should I make a fiberglass cocoon to put around the lamp base. Read the fine print on the can. It may list the maximum temperature rating. I'd try a fiberglass cocoon first just because it's easily reversible if it doesn't work. When your unit is running is the lamp test point voltage correct? Ed The unit now achieves lock in about an hour. The only other thing I did was to replace the caps in the main supply. Any thoughts on the insulation? Don H ___ 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] Wilkinson TDC
The circuit for the Tek 2440 is in the manual. However, it isnt that well executed. Relying on the overload recovery of an unclamped jfet input opamp limits the recovery time and performance as does the unisolated input capacitance of the opamps used to control the current source transistor emitter currents, the Wavecrest interpolators which incorporate several refinements to improve the transient response of the current sources are far better in this respect. The Wavecrest interpolators also have sub picosecond resolution although their noise is around 3-6ps. Bruce paul swed wrote: Do you have an actual circuit? It looks a lot like the old hp5360 counter interpolator. Regards Paul On Sun, Apr 29, 2012 at 3:51 AM, Bruce Griffithsbruce.griffi...@xtra.co.nz wrote: The essentials of a Wikinson TDC can be simplified to the attached circuit which only requires the addition of a zero crossing comparator to monitor the voltage across the capacitor C1. A few refinements to improve the capacitor charging current switching transitions and the addition of an upper voltage clamp together with the use of faster transistors may be useful. Apart from level shifting to drive the npn and pnp longtailed pairs only a 2 bit shift register is required for the synchronisers reducing the number of external (to an FPGA or CPLD) logic packages required. The jitter of the count logic etc., isn't critical and can be implemented in an FPGA or CPLD. With a 100MHz synchroniser and counter clock a resolution of 10ps can be achieved with a 1000:1 ratio between charge and discharge currents. Bruce ___ 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. ___ 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] General Technology Corp model 304b
I have a working GTC 304 too. Mine is marked Sperry s/n 002 (!!) but has another GTC s/n inside the cover. Mine also locks in one hour, time for the xtal oven to reach temperature. It is installed in my frequency standards rack at work. If Ed needs any info, let me know. I never dismounted the Rb cell, since it works... ;-) 73 - Marco IK1ODO ___ 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] Antique Rb Standard - Thanks, Pictures, Parts Request, Question
Hi Ed, On 4/29/2012 12:28 PM, ed breya wrote: Yes, very nice pictures. That thing is really built and looks like it should be easy to work on and experiment with. I still have to say that I doubt the cavity is off-tune unless something serious happened to it mechanically. Is it even adjustable? Yes, it's quite adjustable. The end screws in and out over a range of ~0.9 to 1.07 inches for the inside length of the cavity. I suspect that the reason the cavity was mistuned wasn't because of the cavity changing mechanically but because the cell drifted over the 40+ years since it was manufactured. After all, isn't that what happens to Rb standards? If so, maybe someone previously tried to adjust it and messed up. If not, or it appears original, then I think any mistuning will be in the multiplier instead. Unfortunately I won't be able to test/adjust the multiplier until I can build an extender card. But even if the multiplier was slightly off ( can an analog multiplier by _slightly_ off?), wouldn't that just change the required frequency for the OCXO? The SRD would still be an exact multiplier and if the physics package was working properly, I should see the fundamental and 2nd harmonic as expected. You can sweep the cavity by placing coupling loops in there, and then see what happens as you go say +/- 100 MHz around the desired center, and then at narrower sweeps. You should get an observable peak at or near the right frequency, and it should be broad enough to include the ideal Rb frequency. When the excitation lamp is on and the cell has some light going through, there should be some absorption, and the cavity Q may decrease a bit, but I doubt it will have much effect. You can try this by sweeping with everything off, and then with the lamp on to see if it's noticeable. My test equipment isn't good enough for that. I was able to look for frequencies in the cavity and saw the 92nd, 93rd, and 95th harmonics of the driver frequency. But the Rb frequency is at the 98th harmonic. I have retuned the cavity so that the strongest signals are the 97th and 98th harmonic. I hope to get things reassembled today to see if it changed anything. Ed Also, as someone else mentioned, it's good to see fully-utilized bench space in the background - plenty of stuff everywhere, at your fingertips. I especially liked the open-sided desktop PC. All of my garage PCs are just like that (I don't even know if I can find the covers) - it gives better cooling, is easy to modify and experiment with, and provides some handy storage space that otherwise would be wasted. Ed ___ 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] Antique Rb Standard - Thanks, Pictures, Parts Request, Question
If the Rb cell drifted enough (maybe if it was filled with water) to de-tune the mechanical cavity resonator, it wouldn't work at all. Only a small amount of the RF power in the cavity is coupled into the Rb gas. The bandwidth of the Rb resonance is a fraction of a Hz (Q in the millions), while the bandwidth of the cavity is probably 20-50 MHz, (Q may be up to 100). The multiplier will multiply frequency by integers at each stage, but each stage is tuned to maximize its response at the desired harmonic. You have a chain of these, each needing to be peaked to get the net result - enough power at the right frequency to drive the SRD. Then the SRD has to be optimally biased to maximize its power output at the desired harmonic. Then the cavity has to prefer that particular (98th or whichever) spur - but it isn't an extremely narrow filter - it can't be since it's just a single section. It has to be good enough to reasonably attenuate the nearby spurs spaced at around 69 MHz away, and to be the tuned load for the SRD to maximize the power at the desired frequency. So, the guts need to provide the cascade of discrete frequencies that ultimately lands one near the Rb resonance in order to detect it, but each stage and each part has to be right for it to work. The Rb resonance is by far the most stable of all of the parts of the system - even after 40 years or any number of years. Ed ___ 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] General Technology Corp model 304b
On 4/29/2012 1:36 PM, Ed Palmer wrote: Thank you Ed,Paul,and Marco for the reply's The foam I was referring to is or was around ceramic base were the igniter wire goes . Yes my wire also broke loose however I do not want to disassemble any more than I have to. I think that just inserting it back in to the hole and securing in some way should work. I do not know what the potential is but I have seen a spark jump at least an eight of an inch. Tell me about the lamp voltage test point. My manual has no mention of it? Were is it located? In you first posting I think you mentioned some grounding problems. On this unit there is a three pin amp connector on the rear on mine the bottom pin -20 must be grounded or the unit will not work. The red light will come on very bright but nothing else works.I believe you can also ground the +20 this allows this to work in various ground polarity systems IE telco systems +ground. Perhaps I am wrong. I have Hp113,Hp115 that caution you on the ground polarity of the systems you are installing them in. I think all the -20 floats from chassis ground until they get to that rear plug. Thanks for foam an fiberglass suggestions. Hi Don, You know that we're going to be swapping many emails, don't you? :-) On 4/29/2012 11:16 AM, Donald Henderickx wrote: After following Ed Palmer's thread on 304b restoration,I was inspired to get my GTC (tracor) 304b ser#279 going. It seems that the failure of this unit was the break down of the foam that was wrapped around the vcxo located inside the control box. The vapors or the moisture the foam collected corroded the steel fasteners and caused the switches to become intermittent. The foam around my OCXO is still in great shape. Still spongy and providing lots of holding force for the OCXO. My unit is serial #449. The replacement of the foam in the control box is not that much of a problem,what I need help with is what to use around the Rb lamp base. The foam has turned to powder. Do you mean foam around the back end of the lamp where the wire lead comes out or the foam that surrounds the reflector (#16 in the picture in the patent that describes the lamp (3311775))? My #16 foam is really solid. Should I try Home foam sealant? The cell's ,of this seem about the same as the old foam.Will it take the heat?Should I make a fiberglass cocoon to put around the lamp base. Read the fine print on the can. It may list the maximum temperature rating. I'd try a fiberglass cocoon first just because it's easily reversible if it doesn't work. When your unit is running is the lamp test point voltage correct? Ed The unit now achieves lock in about an hour. The only other thing I did was to replace the caps in the main supply. Any thoughts on the insulation? Don H ___ 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] Antique Rb Standard - Thanks, Pictures, Parts Request, Question
I will strongly agree about the cavity and not tuning it. The key is the multiplication chain and unless the srd is bad the rest of the chains pretty reasonable in the frequencies used. Typically a fair amount of power just before the srd. Regards paul. On Sun, Apr 29, 2012 at 4:19 PM, ed breya e...@telight.com wrote: If the Rb cell drifted enough (maybe if it was filled with water) to de-tune the mechanical cavity resonator, it wouldn't work at all. Only a small amount of the RF power in the cavity is coupled into the Rb gas. The bandwidth of the Rb resonance is a fraction of a Hz (Q in the millions), while the bandwidth of the cavity is probably 20-50 MHz, (Q may be up to 100). The multiplier will multiply frequency by integers at each stage, but each stage is tuned to maximize its response at the desired harmonic. You have a chain of these, each needing to be peaked to get the net result - enough power at the right frequency to drive the SRD. Then the SRD has to be optimally biased to maximize its power output at the desired harmonic. Then the cavity has to prefer that particular (98th or whichever) spur - but it isn't an extremely narrow filter - it can't be since it's just a single section. It has to be good enough to reasonably attenuate the nearby spurs spaced at around 69 MHz away, and to be the tuned load for the SRD to maximize the power at the desired frequency. So, the guts need to provide the cascade of discrete frequencies that ultimately lands one near the Rb resonance in order to detect it, but each stage and each part has to be right for it to work. The Rb resonance is by far the most stable of all of the parts of the system - even after 40 years or any number of years. Ed __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] Trimble Thunderbolt GPS Antenna
Agreed, I picked up a new in box Symmetricom 58532 this winter. I was very surprised to get a usable signal from indoors (through attic, shingles, 4 inches of ice and 2 - 3 feet of snow). From the same room, my SIRFIII based GPSes would take 5 minutes or more to warm-lock and would randomly drop. Location output was also semi-random walk over 100+ meters. Normally these little SIRFIII units are 5 seconds to warm lock and within 2 meters. Now that the roof is almost clear of snow I am looking forward to seeing how well it will do with an actual sky view. On 4/29/12 8:46 AM, Mark Spencer wrote: I've been pleased with the performance of the Symmetricom 58532. I believe it has more gain than many other antennas and my case feeds a lengthy run (maybe 80 feet or so ?) of RG58 whichin turn feeds my Thunderbolt. --- On Sun, 4/29/12, Ken Kubick kenkub...@hotmail.com wrote: From: Ken Kubick kenkub...@hotmail.com Subject: [time-nuts] Trimble Thunderbolt GPS Antenna To: Time Nuts time-nuts@febo.com Received: Sunday, April 29, 2012, 12:29 PM Hi, Time-Nuts guys I just baught a Trimble Thunderbolt on ebay. I am in need of an antenna, there are so many on ebay I am not sure which one to get. Maybe someone could point me in the right direction? Thankyou Ken Kubick kenkub...@hotmail.com ___ 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. ___ 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] General Technology Corp model 304b
Hi Don, On 4/29/2012 2:54 PM, Donald Henderickx wrote: On 4/29/2012 1:36 PM, Ed Palmer wrote: Thank you Ed,Paul,and Marco for the reply's The foam I was referring to is or was around ceramic base were the igniter wire goes . Yes my wire also broke loose however I do not want to disassemble any more than I have to. I think that just inserting it back in to the hole and securing in some way should work. I do not know what the potential is but I have seen a spark jump at least an eight of an inch. The igniter wire has to be connected to the base of the lamp. The patent explains it quite well. Just inserting it into the hole in the ceramic is unlikely to work. I don't know what the voltage is, but the capacitor that stores the voltage is rated for 400V. Does the foam look original? It definitely isn't on mine so I wasn't sure if it was supposed to be there or not. The patent describes how the base is the coolest part of the bulb. I don't know if a foam covering is appropriate. Tell me about the lamp voltage test point. My manual has no mention of it? Were is it located? All the test points are described on page 5-3 of the manual. The lamp heater test point is the sixth one from the top. Ground is the seventh point. In you first posting I think you mentioned some grounding problems. On this unit there is a three pin amp connector on the rear on mine the bottom pin -20 must be grounded or the unit will not work. The red light will come on very bright but nothing else works.I believe you can also ground the +20 this allows this to work in various ground polarity systems IE telco systems +ground. Perhaps I am wrong. Do you mean the 3 pin round connector on the back? That's for an external DC power supply. It has no other function and grounding the bottom pin (which is ground) shouldn't make any difference. Ed I have Hp113,Hp115 that caution you on the ground polarity of the systems you are installing them in. I think all the -20 floats from chassis ground until they get to that rear plug. Thanks for foam an fiberglass suggestions. Hi Don, You know that we're going to be swapping many emails, don't you? :-) On 4/29/2012 11:16 AM, Donald Henderickx wrote: After following Ed Palmer's thread on 304b restoration,I was inspired to get my GTC (tracor) 304b ser#279 going. It seems that the failure of this unit was the break down of the foam that was wrapped around the vcxo located inside the control box. The vapors or the moisture the foam collected corroded the steel fasteners and caused the switches to become intermittent. The foam around my OCXO is still in great shape. Still spongy and providing lots of holding force for the OCXO. My unit is serial #449. The replacement of the foam in the control box is not that much of a problem,what I need help with is what to use around the Rb lamp base. The foam has turned to powder. Do you mean foam around the back end of the lamp where the wire lead comes out or the foam that surrounds the reflector (#16 in the picture in the patent that describes the lamp (3311775))? My #16 foam is really solid. Should I try Home foam sealant? The cell's ,of this seem about the same as the old foam.Will it take the heat?Should I make a fiberglass cocoon to put around the lamp base. Read the fine print on the can. It may list the maximum temperature rating. I'd try a fiberglass cocoon first just because it's easily reversible if it doesn't work. When your unit is running is the lamp test point voltage correct? Ed The unit now achieves lock in about an hour. The only other thing I did was to replace the caps in the main supply. Any thoughts on the insulation? Don H ___ 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] Wilkinson TDC
On Mon, 30 Apr 2012 06:51:37 +1200, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The circuit for the Tek 2440 is in the manual. However, it isnt that well executed. I like using the 2440 as an example because the design and theory are readily available online. Its execution only had to be good enough for 40ps equivalent time sampling and less than 50 measurements per second. Unfortunately the self calibration logic is obfuscated inside of a Tektronix black box custom ASIC. Relying on the overload recovery of an unclamped jfet input opamp limits the recovery time and performance as does the unisolated input capacitance of the opamps used to control the current source transistor emitter currents, the Wavecrest interpolators which incorporate several refinements to improve the transient response of the current sources are far better in this respect. By unclamped JFET input opamps do you mean U590B and U590C which are used to adjust the ramp start to zero volts and operate open loop during the measurement? With such a slow measurement rate, that feedback loop has at least 20ms to complete settling. I notice that they attenuated the open loop gain by a factor of 6. I wonder if that was to lower the noise or to add phase margin to the control loop. The Wavecrest interpolators also have sub picosecond resolution although their noise is around 3-6ps. Is there a published schematic and theory for the Wavecrest other than the patent? The best information I have found through Google is from your own posts here. Bruce paul swed wrote: Do you have an actual circuit? It looks a lot like the old hp5360 counter interpolator. Regards Paul On Sun, Apr 29, 2012 at 3:51 AM, Bruce Griffithsbruce.griffi...@xtra.co.nz wrote: The essentials of a Wikinson TDC can be simplified to the attached circuit which only requires the addition of a zero crossing comparator to monitor the voltage across the capacitor C1. A few refinements to improve the capacitor charging current switching transitions and the addition of an upper voltage clamp together with the use of faster transistors may be useful. Apart from level shifting to drive the npn and pnp longtailed pairs only a 2 bit shift register is required for the synchronisers reducing the number of external (to an FPGA or CPLD) logic packages required. The jitter of the count logic etc., isn't critical and can be implemented in an FPGA or CPLD. With a 100MHz synchroniser and counter clock a resolution of 10ps can be achieved with a 1000:1 ratio between charge and discharge currents. ___ 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] General Technology Corp model 304b
Curious is the manual online? Would be interesting to look at. On Sun, Apr 29, 2012 at 6:33 PM, Ed Palmer ed_pal...@sasktel.net wrote: Hi Don, On 4/29/2012 2:54 PM, Donald Henderickx wrote: On 4/29/2012 1:36 PM, Ed Palmer wrote: Thank you Ed,Paul,and Marco for the reply's The foam I was referring to is or was around ceramic base were the igniter wire goes . Yes my wire also broke loose however I do not want to disassemble any more than I have to. I think that just inserting it back in to the hole and securing in some way should work. I do not know what the potential is but I have seen a spark jump at least an eight of an inch. The igniter wire has to be connected to the base of the lamp. The patent explains it quite well. Just inserting it into the hole in the ceramic is unlikely to work. I don't know what the voltage is, but the capacitor that stores the voltage is rated for 400V. Does the foam look original? It definitely isn't on mine so I wasn't sure if it was supposed to be there or not. The patent describes how the base is the coolest part of the bulb. I don't know if a foam covering is appropriate. Tell me about the lamp voltage test point. My manual has no mention of it? Were is it located? All the test points are described on page 5-3 of the manual. The lamp heater test point is the sixth one from the top. Ground is the seventh point. In you first posting I think you mentioned some grounding problems. On this unit there is a three pin amp connector on the rear on mine the bottom pin -20 must be grounded or the unit will not work. The red light will come on very bright but nothing else works.I believe you can also ground the +20 this allows this to work in various ground polarity systems IE telco systems +ground. Perhaps I am wrong. Do you mean the 3 pin round connector on the back? That's for an external DC power supply. It has no other function and grounding the bottom pin (which is ground) shouldn't make any difference. Ed I have Hp113,Hp115 that caution you on the ground polarity of the systems you are installing them in. I think all the -20 floats from chassis ground until they get to that rear plug. Thanks for foam an fiberglass suggestions. Hi Don, You know that we're going to be swapping many emails, don't you? :-) On 4/29/2012 11:16 AM, Donald Henderickx wrote: After following Ed Palmer's thread on 304b restoration,I was inspired to get my GTC (tracor) 304b ser#279 going. It seems that the failure of this unit was the break down of the foam that was wrapped around the vcxo located inside the control box. The vapors or the moisture the foam collected corroded the steel fasteners and caused the switches to become intermittent. The foam around my OCXO is still in great shape. Still spongy and providing lots of holding force for the OCXO. My unit is serial #449. The replacement of the foam in the control box is not that much of a problem,what I need help with is what to use around the Rb lamp base. The foam has turned to powder. Do you mean foam around the back end of the lamp where the wire lead comes out or the foam that surrounds the reflector (#16 in the picture in the patent that describes the lamp (3311775))? My #16 foam is really solid. Should I try Home foam sealant? The cell's ,of this seem about the same as the old foam.Will it take the heat?Should I make a fiberglass cocoon to put around the lamp base. Read the fine print on the can. It may list the maximum temperature rating. I'd try a fiberglass cocoon first just because it's easily reversible if it doesn't work. When your unit is running is the lamp test point voltage correct? Ed The unit now achieves lock in about an hour. The only other thing I did was to replace the caps in the main supply. Any thoughts on the insulation? Don H __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] Antique Rb Standard - Thanks, Pictures, Parts Request, Question
Hi Ed, On 04/29/2012 05:46 PM, Ed Palmer wrote: Hi Magnus, Second, pictures. If anyone is interested, check out http://s701.photobucket.com/albums/ww18/edpalmer42/Tracor%20304-B/ . Nice photos. Thanks. GAS building up. What does GAS mean? Gear Acquisition Syndrome. GAS is a diagnose which I think no time-nut would admit to. ;-) that talks about cavities in general, but the calculations don't work. I'm guessing that the Rb cell is changing the resonant frequency of the cavity. The glass pulls the cavity resonance somewhat, yes. A TE111 resonance mode is typically used, allowing light to enter and leave at the ends of the cylinder. TE011 was used before, but it much larger. Todays modern cells use a loaded cell (dielectrum added) to move the resonance frequency down, which allows much smaller physical cells. This unit is TE011 No dielectric, plain brass - not silver-plated, 2.495 inch diameter @ room temperature, length tunable from ~0.9 to 1.07 inches. Not surprising, and actually I think I've read that during the day. W.J.Riley Rubidium Frequency Standard Primer is a good starting-point, but following the references should help. I think just searching for TE111 mode rubidium cranks out a few interesting things, such as: http://dspace.thapar.edu:8080/dspace/bitstream/10266/968/1/Satyendr_Thesis.pdf Thanks for that link. I have been searching, but it's like panning for gold - lots of sand and dirt and a very few nuggets of gold. Indeed. I have a few more hints on where it can be worth panning, as I have gathered a few books on the subject. Reading Riley's book (as I mentioned above) today has given much more body to the subject. Learning things quickly. While his book isn't heavy on the deep stuff, he summarize it so you get an overview and then gives several hundreds of references. Cheers, Magnus ___ 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] General Technology Corp model 304b
Yes, there's a partial copy of the manual online. It's missing a few schematics, but is otherwise complete. http://sundry.i2phd.com/ServiceManual_304b.pdf Ed On 4/29/2012 5:18 PM, paul swed wrote: Curious is the manual online? Would be interesting to look at. On Sun, Apr 29, 2012 at 6:33 PM, Ed Palmered_pal...@sasktel.net wrote: Hi Don, On 4/29/2012 2:54 PM, Donald Henderickx wrote: On 4/29/2012 1:36 PM, Ed Palmer wrote: Thank you Ed,Paul,and Marco for the reply's The foam I was referring to is or was around ceramic base were the igniter wire goes . Yes my wire also broke loose however I do not want to disassemble any more than I have to. I think that just inserting it back in to the hole and securing in some way should work. I do not know what the potential is but I have seen a spark jump at least an eight of an inch. The igniter wire has to be connected to the base of the lamp. The patent explains it quite well. Just inserting it into the hole in the ceramic is unlikely to work. I don't know what the voltage is, but the capacitor that stores the voltage is rated for 400V. Does the foam look original? It definitely isn't on mine so I wasn't sure if it was supposed to be there or not. The patent describes how the base is the coolest part of the bulb. I don't know if a foam covering is appropriate. Tell me about the lamp voltage test point. My manual has no mention of it? Were is it located? All the test points are described on page 5-3 of the manual. The lamp heater test point is the sixth one from the top. Ground is the seventh point. In you first posting I think you mentioned some grounding problems. On this unit there is a three pin amp connector on the rear on mine the bottom pin -20 must be grounded or the unit will not work. The red light will come on very bright but nothing else works.I believe you can also ground the +20 this allows this to work in various ground polarity systems IE telco systems +ground. Perhaps I am wrong. Do you mean the 3 pin round connector on the back? That's for an external DC power supply. It has no other function and grounding the bottom pin (which is ground) shouldn't make any difference. Ed I have Hp113,Hp115 that caution you on the ground polarity of the systems you are installing them in. I think all the -20 floats from chassis ground until they get to that rear plug. Thanks for foam an fiberglass suggestions. Hi Don, You know that we're going to be swapping many emails, don't you? :-) On 4/29/2012 11:16 AM, Donald Henderickx wrote: After following Ed Palmer's thread on 304b restoration,I was inspired to get my GTC (tracor) 304b ser#279 going. It seems that the failure of this unit was the break down of the foam that was wrapped around the vcxo located inside the control box. The vapors or the moisture the foam collected corroded the steel fasteners and caused the switches to become intermittent. The foam around my OCXO is still in great shape. Still spongy and providing lots of holding force for the OCXO. My unit is serial #449. The replacement of the foam in the control box is not that much of a problem,what I need help with is what to use around the Rb lamp base. The foam has turned to powder. Do you mean foam around the back end of the lamp where the wire lead comes out or the foam that surrounds the reflector (#16 in the picture in the patent that describes the lamp (3311775))? My #16 foam is really solid. Should I try Home foam sealant? The cell's ,of this seem about the same as the old foam.Will it take the heat?Should I make a fiberglass cocoon to put around the lamp base. Read the fine print on the can. It may list the maximum temperature rating. I'd try a fiberglass cocoon first just because it's easily reversible if it doesn't work. When your unit is running is the lamp test point voltage correct? Ed The unit now achieves lock in about an hour. The only other thing I did was to replace the caps in the main supply. Any thoughts on the insulation? Don H ___ 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] Antique Rb Standard - Thanks, Pictures, Parts Request, Question
On 2012-04-29 16:21, Magnus Danielson wrote: Hi Ed, On 04/29/2012 05:46 PM, Ed Palmer wrote: Hi Magnus, Second, pictures. If anyone is interested, check out http://s701.photobucket.com/albums/ww18/edpalmer42/Tracor%20304-B/ . Nice photos. Thanks. GAS building up. What does GAS mean? Gear Acquisition Syndrome. GAS is a diagnose which I think no time-nut would admit to. ;-) hey GAS happens to musicians too. the reason I have 12 guitars is because I have really held back on buying more. anyways the wife has three guitars and 4 keyboards, my daughter has two pianos and three flutes and two piccolos. let's not talk about my radios :) ___ 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] PICDIV for 1 min pulses
Hi The problem is a bit more complex than simply getting a pulse at the second / minute. At least back when I last got into this - the pulses need to be the proper width. In some cases you need pairs of pulses in the right order. Simple solution - feed the Rb 10 MHz into the clock input on a PIC (or what ever) and write some simple code to generate exactly what is needed for the specific stepper or escarpment. Since the Rb is a power hog there's no advantage to low power in this case. For the 5680's you need some outboard stuff anyway. Just drop the PIC onto the board with the +5 regulator and DB-9 connector on it. Bob On Apr 28, 2012, at 6:29 PM, Magnus Danielson wrote: Fellow time-nuts (and Tom in particular), I am now seeing the effects of the article a few days earlier. At least two friends wants to play around. One of my friends wants to drive a classic clock from a rubidium. I recommended him to take a look at the PICDIV and he kind of liked it. So, he would need a minute pulse and a second pulse. Wouldn't it be sweet if the PICDIV was able to crank out these pulses? As I recall from his brief discussion, there is two styles of clock-drive. I thought that this would be a little inspirational to others, so therefore I toss it to the list than just Tom. Cheers, Magnus ___ 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.
[time-nuts] Loran C back on
Hi all; Receiving Wildwood NJ GRI 8970 here in northern Indiana again today. FYI Rich - Original Message - From: time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Sunday, April 29, 2012 8:21 PM Subject: time-nuts Digest, Vol 93, Issue 152 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: Wilkinson TDC (David) 2. Re: General Technology Corp model 304b (paul swed) 3. Re: Antique Rb Standard - Thanks, Pictures, Parts Request, Question (Magnus Danielson) 4. Re: General Technology Corp model 304b (Ed Palmer) 5. Re: Antique Rb Standard - Thanks, Pictures, Parts Request, Question (Cliff Sojourner) 6. Re: PICDIV for 1 min pulses (Bob Camp) -- Message: 1 Date: Sun, 29 Apr 2012 18:17:10 -0500 From: David davidwh...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Wilkinson TDC Message-ID: mr9rp7lgruccve3eaq954sr1og26575...@4ax.com Content-Type: text/plain; charset=us-ascii On Mon, 30 Apr 2012 06:51:37 +1200, Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: The circuit for the Tek 2440 is in the manual. However, it isnt that well executed. I like using the 2440 as an example because the design and theory are readily available online. Its execution only had to be good enough for 40ps equivalent time sampling and less than 50 measurements per second. Unfortunately the self calibration logic is obfuscated inside of a Tektronix black box custom ASIC. Relying on the overload recovery of an unclamped jfet input opamp limits the recovery time and performance as does the unisolated input capacitance of the opamps used to control the current source transistor emitter currents, the Wavecrest interpolators which incorporate several refinements to improve the transient response of the current sources are far better in this respect. By unclamped JFET input opamps do you mean U590B and U590C which are used to adjust the ramp start to zero volts and operate open loop during the measurement? With such a slow measurement rate, that feedback loop has at least 20ms to complete settling. I notice that they attenuated the open loop gain by a factor of 6. I wonder if that was to lower the noise or to add phase margin to the control loop. The Wavecrest interpolators also have sub picosecond resolution although their noise is around 3-6ps. Is there a published schematic and theory for the Wavecrest other than the patent? The best information I have found through Google is from your own posts here. Bruce paul swed wrote: Do you have an actual circuit? It looks a lot like the old hp5360 counter interpolator. Regards Paul On Sun, Apr 29, 2012 at 3:51 AM, Bruce Griffithsbruce.griffi...@xtra.co.nz wrote: The essentials of a Wikinson TDC can be simplified to the attached circuit which only requires the addition of a zero crossing comparator to monitor the voltage across the capacitor C1. A few refinements to improve the capacitor charging current switching transitions and the addition of an upper voltage clamp together with the use of faster transistors may be useful. Apart from level shifting to drive the npn and pnp longtailed pairs only a 2 bit shift register is required for the synchronisers reducing the number of external (to an FPGA or CPLD) logic packages required. The jitter of the count logic etc., isn't critical and can be implemented in an FPGA or CPLD. With a 100MHz synchroniser and counter clock a resolution of 10ps can be achieved with a 1000:1 ratio between charge and discharge currents. -- Message: 2 Date: Sun, 29 Apr 2012 19:18:13 -0400 From: paul swed paulsw...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] General Technology Corp model 304b Message-ID: CAD2JfAi67wi3c9Ea4p+Qcx=daowx-28JNAuw_q5cA_ZY+TDr=q...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 Curious is the manual online? Would be interesting to look at. On Sun, Apr 29, 2012 at 6:33 PM, Ed Palmer ed_pal...@sasktel.net wrote: Hi Don, On 4/29/2012 2:54 PM, Donald Henderickx wrote: On 4/29/2012 1:36 PM, Ed Palmer wrote: Thank you Ed,Paul,and Marco for the reply's The foam I was referring to is or was around ceramic base were the igniter wire goes . Yes my wire also broke loose however I do not want to disassemble any more than I have to. I think that just inserting it back in to the hole and securing in some way
Re: [time-nuts] General Technology Corp model 304b
On 4/29/2012 6:27 PM, Ed Palmer wrote: Yes, there's a partial copy of the manual online. It's missing a few schematics, but is otherwise complete. http://sundry.i2phd.com/ServiceManual_304b.pdf Ed The bottom pin is not chassis ground,on this unit. The foam looked original before in crumbled. The 400v cap in the ignitor circuit dumps into the primary of a autotransformer, from the spark I observed I would i would guess 10kv so I do not think intimate contact is necessary You asked about lamp voltage test point not lamp heater test point,that is what confused me. I will check it when I power it back up. On 4/29/2012 5:18 PM, paul swed wrote: Curious is the manual online? Would be interesting to look at. On Sun, Apr 29, 2012 at 6:33 PM, Ed Palmered_pal...@sasktel.net wrote: Hi Don, On 4/29/2012 2:54 PM, Donald Henderickx wrote: On 4/29/2012 1:36 PM, Ed Palmer wrote: Thank you Ed,Paul,and Marco for the reply's The foam I was referring to is or was around ceramic base were the igniter wire goes . Yes my wire also broke loose however I do not want to disassemble any more than I have to. I think that just inserting it back in to the hole and securing in some way should work. I do not know what the potential is but I have seen a spark jump at least an eight of an inch. The igniter wire has to be connected to the base of the lamp. The patent explains it quite well. Just inserting it into the hole in the ceramic is unlikely to work. I don't know what the voltage is, but the capacitor that stores the voltage is rated for 400V. Does the foam look original? It definitely isn't on mine so I wasn't sure if it was supposed to be there or not. The patent describes how the base is the coolest part of the bulb. I don't know if a foam covering is appropriate. Tell me about the lamp voltage test point. My manual has no mention of it? Were is it located? All the test points are described on page 5-3 of the manual. The lamp heater test point is the sixth one from the top. Ground is the seventh point. In you first posting I think you mentioned some grounding problems. On this unit there is a three pin amp connector on the rear on mine the bottom pin -20 must be grounded or the unit will not work. The red light will come on very bright but nothing else works.I believe you can also ground the +20 this allows this to work in various ground polarity systems IE telco systems +ground. Perhaps I am wrong. Do you mean the 3 pin round connector on the back? That's for an external DC power supply. It has no other function and grounding the bottom pin (which is ground) shouldn't make any difference. Ed I have Hp113,Hp115 that caution you on the ground polarity of the systems you are installing them in. I think all the -20 floats from chassis ground until they get to that rear plug. Thanks for foam an fiberglass suggestions. Hi Don, You know that we're going to be swapping many emails, don't you? :-) On 4/29/2012 11:16 AM, Donald Henderickx wrote: After following Ed Palmer's thread on 304b restoration,I was inspired to get my GTC (tracor) 304b ser#279 going. It seems that the failure of this unit was the break down of the foam that was wrapped around the vcxo located inside the control box. The vapors or the moisture the foam collected corroded the steel fasteners and caused the switches to become intermittent. The foam around my OCXO is still in great shape. Still spongy and providing lots of holding force for the OCXO. My unit is serial #449. The replacement of the foam in the control box is not that much of a problem,what I need help with is what to use around the Rb lamp base. The foam has turned to powder. Do you mean foam around the back end of the lamp where the wire lead comes out or the foam that surrounds the reflector (#16 in the picture in the patent that describes the lamp (3311775))? My #16 foam is really solid. Should I try Home foam sealant? The cell's ,of this seem about the same as the old foam.Will it take the heat?Should I make a fiberglass cocoon to put around the lamp base. Read the fine print on the can. It may list the maximum temperature rating. I'd try a fiberglass cocoon first just because it's easily reversible if it doesn't work. When your unit is running is the lamp test point voltage correct? Ed The unit now achieves lock in about an hour. The only other thing I did was to replace the caps in the main supply. Any thoughts on the insulation? Don H ___ 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] Loran C back on
Rich, Thanks for the heads up. I will turn stuff back on. Stan, W1LE Cape Cod FN41sr On 4/29/2012 8:26 PM, Rich and Marcia Putz wrote: Hi all; Receiving Wildwood NJ GRI 8970 here in northern Indiana again today. FYI Rich ___ 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] General Technology Corp model 304b
Hi Don, On 4/29/2012 6:41 PM, Donald Henderickx wrote: On 4/29/2012 6:27 PM, Ed Palmer wrote: Yes, there's a partial copy of the manual online. It's missing a few schematics, but is otherwise complete. http://sundry.i2phd.com/ServiceManual_304b.pdf Ed The bottom pin is not chassis ground,on this unit. The bottom pin (pin B) is connected to circuit ground which is connected to chassis ground on my unit and the schematic confirms it. That could be why you have to ground that pin to make your unit work. There appears to be a broken or missing ground somewhere in your unit. The foam looked original before in crumbled. That's good to know. Thanks! The 400v cap in the ignitor circuit dumps into the primary of a autotransformer, from the spark I observed I would i would guess 10kv so I do not think intimate contact is necessary I looked right at the autotransformer on the schematic and still didn't see it. You asked about lamp voltage test point not lamp heater test point,that is what confused me. I will check it when I power it back up. You're right. Sorry for the confusion. This has not been one of my better days. Ed On 4/29/2012 5:18 PM, paul swed wrote: Curious is the manual online? Would be interesting to look at. On Sun, Apr 29, 2012 at 6:33 PM, Ed Palmered_pal...@sasktel.net wrote: Hi Don, On 4/29/2012 2:54 PM, Donald Henderickx wrote: On 4/29/2012 1:36 PM, Ed Palmer wrote: Thank you Ed,Paul,and Marco for the reply's The foam I was referring to is or was around ceramic base were the igniter wire goes . Yes my wire also broke loose however I do not want to disassemble any more than I have to. I think that just inserting it back in to the hole and securing in some way should work. I do not know what the potential is but I have seen a spark jump at least an eight of an inch. The igniter wire has to be connected to the base of the lamp. The patent explains it quite well. Just inserting it into the hole in the ceramic is unlikely to work. I don't know what the voltage is, but the capacitor that stores the voltage is rated for 400V. Does the foam look original? It definitely isn't on mine so I wasn't sure if it was supposed to be there or not. The patent describes how the base is the coolest part of the bulb. I don't know if a foam covering is appropriate. Tell me about the lamp voltage test point. My manual has no mention of it? Were is it located? All the test points are described on page 5-3 of the manual. The lamp heater test point is the sixth one from the top. Ground is the seventh point. In you first posting I think you mentioned some grounding problems. On this unit there is a three pin amp connector on the rear on mine the bottom pin -20 must be grounded or the unit will not work. The red light will come on very bright but nothing else works.I believe you can also ground the +20 this allows this to work in various ground polarity systems IE telco systems +ground. Perhaps I am wrong. Do you mean the 3 pin round connector on the back? That's for an external DC power supply. It has no other function and grounding the bottom pin (which is ground) shouldn't make any difference. Ed I have Hp113,Hp115 that caution you on the ground polarity of the systems you are installing them in. I think all the -20 floats from chassis ground until they get to that rear plug. Thanks for foam an fiberglass suggestions. Hi Don, You know that we're going to be swapping many emails, don't you? :-) On 4/29/2012 11:16 AM, Donald Henderickx wrote: After following Ed Palmer's thread on 304b restoration,I was inspired to get my GTC (tracor) 304b ser#279 going. It seems that the failure of this unit was the break down of the foam that was wrapped around the vcxo located inside the control box. The vapors or the moisture the foam collected corroded the steel fasteners and caused the switches to become intermittent. The foam around my OCXO is still in great shape. Still spongy and providing lots of holding force for the OCXO. My unit is serial #449. The replacement of the foam in the control box is not that much of a problem,what I need help with is what to use around the Rb lamp base. The foam has turned to powder. Do you mean foam around the back end of the lamp where the wire lead comes out or the foam that surrounds the reflector (#16 in the picture in the patent that describes the lamp (3311775))? My #16 foam is really solid. Should I try Home foam sealant? The cell's ,of this seem about the same as the old foam.Will it take the heat?Should I make a fiberglass cocoon to put around the lamp base. Read the fine print on the can. It may list the maximum temperature rating. I'd try a fiberglass cocoon first just because it's easily reversible if it doesn't work. When your unit is running is the lamp test point voltage correct? Ed The unit now achieves lock in about an hour. The
Re: [time-nuts] General Technology Corp model 304b
A first-class engineered unit will have a single point where the chassis and circuit grounds tie together, Sometimes it's a panel, where the i/o connectors are coaxial. I've fixed units with good engineering and sloppy construction where accidental extra common points have caused problems. The bottom pin (pin B) is connected to circuit ground which is connected to chassis ground on my unit and the schematic confirms it. That could be why you have to ground that pin to make your unit work. There appears to be a broken or missing ground somewhere in your unit. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. R. Bacon If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ 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] Wilkinson TDC
Bruce wrote: The essentials of a Wikinson TDC can be simplified to the attached circuit which only requires the addition of a zero crossing comparator to monitor the voltage across the capacitor C1. A few refinements to improve the capacitor charging current switching transitions and the addition of an upper voltage clamp together with the use of faster transistors may be useful. The HFA3096 transistor array (3 NPN + 2 PNP) should do nicely. My simulations show a small but definite improvement in the current switching transitions. BTW, the PNPs in an HFA3096/3128 also pretty much solve the Cb-e feedthrough in a Wenzel-style squaring circuit, giving pretty flat tops on the high output pulses without resorting to diode isolation or other secondary techniques. Best regards, Charles ___ 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] Trimble recommends RG-59 Antenna Cable.
Hi Time-Nuts guys, I was reading the Trimble Thunderbolt manual section 2.1.3 (Antenna Cable). Trimble recommends using RG-59 cable which is 75 ohm coax. Is this a typo or is this correct? I thought that the Trimble Thunderbolt would use a 50 ohm cable and antenna. Thankyou Ken Kubick kenkub...@hotmail.com ___ 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.
