Re: [time-nuts] Efratom SLCR-101 rubidium - what have I just bought?
On 26 December 2013 01:18, Philip Pemberton li...@philpem.me.uk wrote: Hi guys, It seems I must have had a bit too much to drink after Christmas dinner, as I've apparently gone crazy and bought an Efratom SLCR-101 Rubidium frequency standard: http://www.ebay.co.uk/itm/400624911534 I oringallly thought your offer of $75 was accepted and was going to say it was a decent buy at $75 given it needs only a single supply. But then I realised it must be a UK seller, and it was £75 GBP ($123), which does not seem so attractive given the guys from China were at least selling them a lot less with free shipping. But the prices seem to have gone up a lot - IU think I paid about $75 for my rubidums, but now I see the same thing on eBay for two or three times that. I'm not entirely sure why the seller provides a link to a manual which he knows is broken (broken link) to PDF format manual for this module:- http://www.symmetricom.com/media/pdf/manuals/man-lpro.pdf; Perhaps he has a copy and could create you a non-broken link! Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Efratom SLCR-101 rubidium - what have I just bought?
On 26/12/13 09:33, Dr. David Kirkby wrote: I oringallly thought your offer of $75 was accepted and was going to say it was a decent buy at $75 given it needs only a single supply. But then I realised it must be a UK seller, and it was £75 GBP ($123), which does not seem so attractive given the guys from China were at least selling them a lot less with free shipping. The reputable Chinese sellers seem to have run out of SLCRs and LPROs and are now selling the DDS-based FEI 5680s. From what I've been told, the less reputable sellers are selling the 1PPS version of the FEI, claiming it to be 10MHz. Of course, they'll refund you, but they expect you to return it to China at which point it becomes cost-prohibitive. Then there's the customs charge (20% VAT plus a £10 handling fee). So in most cases, buying from China is a bit of a false economy: $75 US at ~$1.5 to £1 = £50 £50 + 20% VAT = £60 Plus the £10 handling fee = £70 So not far off the £75 plus postage (£84 total) I just paid. But the prices seem to have gone up a lot - IU think I paid about $75 for my rubidums, but now I see the same thing on eBay for two or three times that. They've absolutely rocketed. One of two things is happening -- either the supply is drying up, or the sellers are capitalising on the fact that a few prominent Youtube video producers have mentioned rubidium oscillators. It's quite possible that both things are happening at the same time... though how anyone expects to sell a heavily used rubidium standard for $555 US is beyond me. I'd point out how quite a few ebay sellers are trying to peddle junk like oscilloscope probes with cut leads for premium prices, but I think everyone's noticed that by now. I don't even bother with best offer, the sellers I've had experience with won't take more than $10 off the price. US/UK sellers (in my experience at least) seem to be more willing to haggle :) I'm not entirely sure why the seller provides a link to a manual which he knows is broken (broken link) to PDF format manual for this module:- http://www.symmetricom.com/media/pdf/manuals/man-lpro.pdf; Perhaps he has a copy and could create you a non-broken link! The Internet Archive probably has a copy, otherwise there are a ton of copies of that PDF - I think KO4BB has a copy on his manuals archive. Thanks. -- Phil. li...@philpem.me.uk http://www.philpem.me.uk/ ___ 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] Efratom SLCR-101 rubidium - what have I just bought?
On 26 December 2013 11:01, Philip Pemberton li...@philpem.me.uk wrote: Then there's the customs charge (20% VAT plus a £10 handling fee). So in most cases, buying from China is a bit of a false economy: $75 US at ~$1.5 to £1 = £50 £50 + 20% VAT = £60 Plus the £10 handling fee = £70 So not far off the £75 plus postage (£84 total) I just paid. And there was me thinking virtually everything from China was valued at $10 - that has been my experience anyway. They've absolutely rocketed. One of two things is happening -- either the supply is drying up, or the sellers are capitalising on the fact that a few prominent Youtube video producers have mentioned rubidium oscillators. It's quite possible that both things are happening at the same time... though how anyone expects to sell a heavily used rubidium standard for $555 US is beyond me. I've got a couple here I bought a couple of years ago. So far I've not connected them up. I'd point out how quite a few ebay sellers are trying to peddle junk like oscilloscope probes with cut leads for premium prices, but I think everyone's noticed that by now. I don't even bother with best offer, the sellers I've had experience with won't take more than $10 off the price. The trick that sometimes works is to put lots of 8's in the offer. That is seen as a lucky number by many Asian sellers! There is one from Singapore who has had a cal kit on eBay for well over a year http://www.ebay.com/itm/HP-Agilent-85050C-Precision-Mechanical-Calibration-Kit-DC-to-18-GHz-7-mm-/321263641082 He is totally unwilling to negotiate US/UK sellers (in my experience at least) seem to be more willing to haggle :) Its also worth contacting them outside eBay, where you tend to get a better price. In many cases it is possible to work out who they are. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] fast edge, rise time.
Hello, I'm willing to generate a pulse (of some few hundred volts) by discharging a capacitor into a pulse transformer I'm solely interested is the active edge (call it either rise or fall depending on the wiring of the output of the transformer). The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. I would be happy to receive some comments/ideas that may pop out of your heads. Thanks. hope that my quest for fast rise time is not too off topic on this time list... but... there are so many experts on this list that I could not resist ;-) Luis Cupido ct1dmk. p.s. ( I switch a capacitor to GND with a transistor (fet or bipolar). that capacitor has a charging resistor to 48V, transformer has a 9:1 voltage ratio. Pulse average power is quite low a few watt only. At the primary side some 20A of peak current for less than 100ns... and very low duty cycle. ) ___ 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] fast edge, rise time.
On 12/26/13 8:07 AM, ct1dmk wrote: Hello, I'm willing to generate a pulse (of some few hundred volts) by discharging a capacitor into a pulse transformer I'm solely interested is the active edge (call it either rise or fall depending on the wiring of the output of the transformer). ns risetime pulses sounds like fairly straight forward radar stuff. the inductance of the transformer is going to be your challenge, depending on the energy level. What about a non-transformer alternative? Can you just charge your cap up to the few hundred volts and have a switch that can take the voltage? How much energy do you need? You said a few hundred volts, but is that microjoules, joules, or kilojoules? A small triggered spark gap would be one way. There's also the ever popular krytron, which has very good timing accuracy. YOu might look for circuits used for exploding bridge wires (EBW) The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. You want some sort of RF transistor here. What about one of the new LDMOS FETs: some have fairly impressive voltage handling, and if they work at 1 GHz for radar applications, they will work for you. What about stacking a bunch of MMIC RF amplifiers (e.g. like the ERA or GAL from minicircuits) Other traditional approaches to fast pulse generation are avalanche transistors. There's also a variety of interesting pulse forming networks that can generate fast rise time high voltage pulses. Blumlein arrangements are one. Your 100ns pulse is fairly long for a transmission line scheme, though (20-30 m of coax) ___ 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] fast edge, rise time.
The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. I have seen recently two kinds of devices for similar task: MOSFETs and avalanche breakdown transistors. Try the second ones, might be a good fit if the pulsing is not very frequent (say, kHz range). Regards, Marek ___ 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] fast edge, rise time.
On Thu, 26 Dec 2013 16:07:49 + ct1dmk ct1...@gmail.com wrote: The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. First idea that comes to mind is using a bipolar transistor in avalanche mode. There are specialized transistors for this, like the ZTX415[1,2], but you can use 0-8-15 tranistors like a BC548 as well. If using a general purpose transistor, then the avalanche voltage will vary quite a bit from transistor to transistor. Easiest way to get around this is to use a small resistor from base to emiter to drain any charge generated, then insert a fast rising spike into the base. Using this, you can enter the range of the avalanche voltage while surpressing the effect until you want to trigger it. With this you should be able to get into the low ns range, if not even below 1ns. The limiting factor is usually how fast the base voltage can rise. The avalanche voltage for BC548 in my experiments was in the vincinity of 200V. I took the idea from [3], which contains a description of such a pulse generator with a general purpose transistor on page 32. Almost the same circuit can be found in [4]. Attila Kinali [1] ZTX415 datasheet http://www.diodes.com/datasheets/ZTX415.pdf [2] ZTX415 avalanche mode transistore application note 8, by Neil Chadderton, 1996 http://www.diodes.com/_files/products_appnote_pdfs/zetex/an8.pdf [3] A seven-nanosecond comparator for single supply operation, by Jim Williams, 1998 http://cds.linear.com/docs/Application%20Note/an72f.pdf [4] Slew rate verification for wide band amiplifier, by Jim Williams, 2003 http://cds.linear.com/docs/Application%20Note/an94f.pdf -- 1.) Write everything down. 2.) Reduce to the essential. 3.) Stop and question. -- The Habits of Highly Boring People, Chris Sauve ___ 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] Efratom SLCR-101 rubidium - what have I just bought?
I went to the website and at the bottom you can request further information. You might want to try it. If possible use a business address and email... Regards Paul WB8TSL On Thu, Dec 26, 2013 at 12:39 AM, Ed Palmer ed_pal...@sasktel.net wrote: Hi Philip, I also have an SLCR and have found almost no info online. Here's the only thing I found: http://web.archive.org/web/2229191126/http://www. datum.com/prod_slcr.html Ed On 12/25/2013 7:18 PM, Philip Pemberton wrote: Hi guys, It seems I must have had a bit too much to drink after Christmas dinner, as I've apparently gone crazy and bought an Efratom SLCR-101 Rubidium frequency standard: http://www.ebay.co.uk/itm/400624911534 I suspect this will make a nice companion for my new-to-me (read: pre-loved) Racal-Dana 1991 frequency counter... Thing is, I'm finding it hard to find any information on the SLCR-101; there's a lot of information on the LPRO, but this one is a bit of a mystery. How does the SLCR-101 compare to the LPRO-101? If the writing on the unit case is to be believed (third photo in the ebay listing), the lamp voltage is 8.34V. I found some documents which suggest that 6-8V is good for an LPRO, but doesn't explain whether this increases or decreases with age? Is higher better, or lower? Thanks, ___ 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] fast edge, rise time.
Hi If you go the Krytron route you probably will need some fairly fancy transformers as well…. Bob On Dec 26, 2013, at 11:19 AM, Jim Lux jim...@earthlink.net wrote: On 12/26/13 8:07 AM, ct1dmk wrote: Hello, I'm willing to generate a pulse (of some few hundred volts) by discharging a capacitor into a pulse transformer I'm solely interested is the active edge (call it either rise or fall depending on the wiring of the output of the transformer). ns risetime pulses sounds like fairly straight forward radar stuff. the inductance of the transformer is going to be your challenge, depending on the energy level. What about a non-transformer alternative? Can you just charge your cap up to the few hundred volts and have a switch that can take the voltage? How much energy do you need? You said a few hundred volts, but is that microjoules, joules, or kilojoules? A small triggered spark gap would be one way. There's also the ever popular krytron, which has very good timing accuracy. YOu might look for circuits used for exploding bridge wires (EBW) The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. You want some sort of RF transistor here. What about one of the new LDMOS FETs: some have fairly impressive voltage handling, and if they work at 1 GHz for radar applications, they will work for you. What about stacking a bunch of MMIC RF amplifiers (e.g. like the ERA or GAL from minicircuits) Other traditional approaches to fast pulse generation are avalanche transistors. There's also a variety of interesting pulse forming networks that can generate fast rise time high voltage pulses. Blumlein arrangements are one. Your 100ns pulse is fairly long for a transmission line scheme, though (20-30 m of coax) ___ 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] fast edge, rise time.
Look at the Jim Williams application note http://cds.linear.com/docs/en/application-note/an47fa.pdf Regards, David Partridge -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ct1dmk Sent: 26 December 2013 16:08 To: Discussion of precise time and frequency measurement Subject: [time-nuts] fast edge, rise time. Hello, I'm willing to generate a pulse (of some few hundred volts) by discharging a capacitor into a pulse transformer I'm solely interested is the active edge (call it either rise or fall depending on the wiring of the output of the transformer). The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. I would be happy to receive some comments/ideas that may pop out of your heads. Thanks. hope that my quest for fast rise time is not too off topic on this time list... but... there are so many experts on this list that I could not resist ;-) Luis Cupido ct1dmk. p.s. ( I switch a capacitor to GND with a transistor (fet or bipolar). that capacitor has a charging resistor to 48V, transformer has a 9:1 voltage ratio. Pulse average power is quite low a few watt only. At the primary side some 20A of peak current for less than 100ns... and very low duty cycle. ) ___ 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] fast edge, rise time.
On 26 December 2013 16:07, ct1dmk ct1...@gmail.com wrote: Hello, I'm willing to generate a pulse (of some few hundred volts) by discharging a capacitor into a pulse transformer There are probably more modern approaches, but a thryatron is one possibility. Shame I put on in the dump a few months ago. Maybe though they are more suitable for higher voltages. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] fast edge, rise time.
Can you say more about your application? What does your load look like? What pulse shape? There are well-known solutiuons for most problems. As Jim said, a lot depends on the energy you need per pulse. What works for a few mJ will not work for MJ BTW, SCRs probably switch a lot faster than thyratrons. Years ago, I cobbled up a high-current SCR pulser with a few thousand uF cap and stud mounted SCR. It would drive enough current through a length of hook up wire so that the wire would jump off the desk when pulsed. -John = On 26 December 2013 16:07, ct1dmk ct1...@gmail.com wrote: Hello, I'm willing to generate a pulse (of some few hundred volts) by discharging a capacitor into a pulse transformer There are probably more modern approaches, but a thryatron is one possibility. Shame I put on in the dump a few months ago. Maybe though they are more suitable for higher voltages. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] fast edge, rise time.
Years ago I had a cousin who ran a civilian calibration lab. For calibrating scopes, etc, for rise time he used a mercury wetted relay which he claimed had nearly instant rise time and no bounce. Seems that he used a resistive divider and the mercury relay shunted a portion of the divider. With very small inductances and capacitance to slow things down it would seem to be very fast. Al, k9si, retired The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. I would be happy to receive some comments/ideas that may pop out of your heads. Thanks. ___ 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] fast edge, rise time.
There are very fast pulsers, some in NIM, that use a charged coax line and Hg relay to calibrate Pulse Height analyzers. The line length sets the pulse length; the charging voltage, the pulse height. -John Years ago I had a cousin who ran a civilian calibration lab. For calibrating scopes, etc, for rise time he used a mercury wetted relay which he claimed had nearly instant rise time and no bounce. Seems that he used a resistive divider and the mercury relay shunted a portion of the divider. With very small inductances and capacitance to slow things down it would seem to be very fast. Al, k9si, retired The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. I would be happy to receive some comments/ideas that may pop out of your heads. Thanks. ___ 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] fast edge, rise time.
On Thu, 26 Dec 2013 16:07:49 +, ct1dmk wrote: The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. Have a look here Jim Williams on eevblog https://tinyurl.com/nhyvtc3 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] fast edge, rise time.
Am 26.12.2013 17:07, schrieb ct1dmk: p.s. ( I switch a capacitor to GND with a transistor (fet or bipolar). that capacitor has a charging resistor to 48V, transformer has a 9:1 voltage ratio. Pulse average power is quite low a few watt only. At the primary side some 20A of peak current for less than 100ns... and very low duty cycle. ) We once built an ultrasonic pipeline pig with 1024 transmit/receive channels, so everything had to be quite compact. The transmitting parts of the transducers were hit with 350V pulses with a few ns risetime and 50 Ohm source impedance and they rang on their favourite frequency. No transformer at all. We used avalanche transistors to produce the pulses, a small smd bipolar made by Zetex (afaik that's now bought up by Diodes, inc). Old 2N3904 are said to avalanche also quite good. The drawback is the repetition rate. Doing it as a 'normal' amplifier w/o transformer will require a cascode stage but should work also. But then I think you know that already since I've seen your presentation of the TWT switcher PS on the EME meeting in Paris 15?? years ago. :-) 73, Gerhard ___ 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] recovering firmware on TS2100
Fellow nuts, I've got a TS2100 that failed to install/write a flash image of v 4.1 (using firmware from http://ko4bb.com/). Looking at the tcpdump of the packets in flight, I get the sense that the TS2100 isn't liking what I've got to offer it (I'm assuming it's checking for SREC format, not finding it, and aborts the transfer). After several failed attempts to copy the image over (tried atftpd on linux, tftpd on fbsd and osx...), I lost power and the unit is now setting on console port only, using the v1.x recovery rom image. So, access is there, network stack is up, etc. I tried again from the recovery image to copy over v 4.1 to flash -- to avail. Of course, after this failed to work, I noticed that ko4bb's archive of v 4.1 isn't SREC format (and I see many ref'x to the .HEX files as having been provided in SREC format). It looks like what I've got is an actual raw binary image of the executable code, not the SREC equivalent. So, does a guy have to covert this binary to SREC himself, or is there something I can nab right-quick online? ...better yet: can anyone confirm the zip archive on kobb.com is legit, and not corrupt? Best, -Tk ___ 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] fast edge, rise time.
On Thu, 26 Dec 2013 19:38:08 + (UTC) cfo xne...@luna.dyndns.dk wrote: Have a look here Jim Williams on eevblog https://tinyurl.com/nhyvtc3 I advice to be cautious with EEVblog. Dave Jones has a lot of half knowledge and presents that like he knew exactly what he is talking about. His videos usally contain a lot of errors. The videos are usally good enough to get you started with something you dont know anything about, but please double check every information you get from there. Attila Kinali -- 1.) Write everything down. 2.) Reduce to the essential. 3.) Stop and question. -- The Habits of Highly Boring People, Chris Sauve ___ 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] Efratom SLCR-101 rubidium - what have I just bought?
Several observations: The listing is titled and the item is described in the listing text as an EFRATOM LPRO-101 10Mhz Oscillator, but the item in the photos is an SLCR-101. The broken link to a manual appears (by its URL) to be for an LPRO-101, not an SLCR-101. So, even if the link worked, it would not be for the item you bought. While the seller appears to be in the UK, the used stickers are the same (including handwriting) as those applied by an infamous Chinese supplier, who sells from a number of China-based ebay accounts. So the ultimate origin of the item on the surplus market is apparently that Chinese seller. The note, Ex-lab equipment, is almost certainly false unless it means used in my home lab after being decommissioned and sold as surplus by a telcom provider. The lamp voltage is a derived quantity that is a rough indicator of lamp health. The actual voltage range varies from model to model -- I have some where the range is ~14v (new) to ~8v (end of life), others where the range is ~9v to ~3v, and others I have no information on. Without information for the SLCR-101 specifically, you have no way of knowing whether 8.34v is nearly new, mid-life, or barely alive. Since the listing promises an LPRO-101, and you will apparently not be receiving an LPRO-101, you should have grounds to return it. Since the SLCR is further miniaturized from the LPRO, and the performance of rubidium oscillators is generally related to the inverse of their size -- and because of the lack of service information for the SLCR -- that's what I'd be inclined to do. 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] Austron
Hello Time-Nuts! I hope everyone is enjoying their Holiday Season! I have a question - I have been doing a little research lately on the company that used to be in Austin, TX - Austron - they seemed to have filed quite a few patents in areas of interest to our group. Here's one just as an example: https://www.google.com/patents/US5220333?pg=PA1dq=assignee:++austronhl=ensa=Xei=tdq8UoL_EqbQ2wXy14DwCAved=0CDcQ6AEwAA Are there any former Austron people on this list? If so, I would like to have a brief phone conversation with you if that is OK. Just general questions - nothing personal of course. E-Mail could work but could be quicker just to have a brief phone call. I have Skype also if that is easier. Thanks and Happy Holidays! John Westmoreland ___ 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] fast edge, rise time.
Many thanks to all for the nice tips. I may narrow down by saying a few more specs as suggested. The pulse would see a somehow unknown load but for a start I was suggested to have my source with 50ohm impedance so worst case would be a short circuit and therefore the pulse would be a current pulse and would have some 10Amp. Pulse length about 100ns so only some 0.5mJ energy that would die inside the pulse source( this would be the worst case). The 100us repetition rate make a a very small duty cycle of 1/1000 so average power maximum 5W. Since the amplitude and timing parameters are to be controlled (pulse timing come from an FPGA) I really need a solution using that trivial switching element fet or bipolar (and can't really do a more exotic scheme if I cant electronically control the parameters) also I must use a transformer because these short pulse are to be superimposed to another voltage and a transformer becomes very handy to do that. I interrupt the wire and insert the secondary there to add the pulses. The challenge I'm facing is on the device either RF FET or Biplolar tr etc. and surrounding circuits, transformer, etc. this to achieve the 4ns (or 5ns). (the transformer I have in mind is something very similar to those transformers on the final stages of HF/VHF ham radio amps, coax cables and ferrite cores) any suggestion regarding devices etc ?... Thanks for all comments. Luis Cupido. ___ 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] fast edge, rise time.
Are only the amplitude and rep rate variable, or do you vary the width too? -John = Many thanks to all for the nice tips. I may narrow down by saying a few more specs as suggested. The pulse would see a somehow unknown load but for a start I was suggested to have my source with 50ohm impedance so worst case would be a short circuit and therefore the pulse would be a current pulse and would have some 10Amp. Pulse length about 100ns so only some 0.5mJ energy that would die inside the pulse source( this would be the worst case). The 100us repetition rate make a a very small duty cycle of 1/1000 so average power maximum 5W. Since the amplitude and timing parameters are to be controlled (pulse timing come from an FPGA) I really need a solution using that trivial switching element fet or bipolar (and can't really do a more exotic scheme if I cant electronically control the parameters) also I must use a transformer because these short pulse are to be superimposed to another voltage and a transformer becomes very handy to do that. I interrupt the wire and insert the secondary there to add the pulses. The challenge I'm facing is on the device either RF FET or Biplolar tr etc. and surrounding circuits, transformer, etc. this to achieve the 4ns (or 5ns). (the transformer I have in mind is something very similar to those transformers on the final stages of HF/VHF ham radio amps, coax cables and ferrite cores) any suggestion regarding devices etc ?... Thanks for all comments. Luis Cupido. ___ 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] fast edge, rise time.
Hi Unless you want run for 1 second, that rules out a Krytron. Length of operation also impacts some of the other implementations. Bob On Dec 26, 2013, at 9:16 PM, ct1dmk ct1...@gmail.com wrote: Many thanks to all for the nice tips. I may narrow down by saying a few more specs as suggested. The pulse would see a somehow unknown load but for a start I was suggested to have my source with 50ohm impedance so worst case would be a short circuit and therefore the pulse would be a current pulse and would have some 10Amp. Pulse length about 100ns so only some 0.5mJ energy that would die inside the pulse source( this would be the worst case). The 100us repetition rate make a a very small duty cycle of 1/1000 so average power maximum 5W. Since the amplitude and timing parameters are to be controlled (pulse timing come from an FPGA) I really need a solution using that trivial switching element fet or bipolar (and can't really do a more exotic scheme if I cant electronically control the parameters) also I must use a transformer because these short pulse are to be superimposed to another voltage and a transformer becomes very handy to do that. I interrupt the wire and insert the secondary there to add the pulses. The challenge I'm facing is on the device either RF FET or Biplolar tr etc. and surrounding circuits, transformer, etc. this to achieve the 4ns (or 5ns). (the transformer I have in mind is something very similar to those transformers on the final stages of HF/VHF ham radio amps, coax cables and ferrite cores) any suggestion regarding devices etc ?... Thanks for all comments. Luis Cupido. ___ 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] fast edge, rise time.
There are some good alternatives to krytrons. Just don't expect to be able to afford or export them. ;) On Dec 26, 2013, at 21:26, Bob Camp li...@rtty.us wrote: Hi Unless you want run for 1 second, that rules out a Krytron. Length of operation also impacts some of the other implementations. Bob On Dec 26, 2013, at 9:16 PM, ct1dmk ct1...@gmail.com wrote: Many thanks to all for the nice tips. I may narrow down by saying a few more specs as suggested. The pulse would see a somehow unknown load but for a start I was suggested to have my source with 50ohm impedance so worst case would be a short circuit and therefore the pulse would be a current pulse and would have some 10Amp. Pulse length about 100ns so only some 0.5mJ energy that would die inside the pulse source( this would be the worst case). The 100us repetition rate make a a very small duty cycle of 1/1000 so average power maximum 5W. Since the amplitude and timing parameters are to be controlled (pulse timing come from an FPGA) I really need a solution using that trivial switching element fet or bipolar (and can't really do a more exotic scheme if I cant electronically control the parameters) also I must use a transformer because these short pulse are to be superimposed to another voltage and a transformer becomes very handy to do that. I interrupt the wire and insert the secondary there to add the pulses. The challenge I'm facing is on the device either RF FET or Biplolar tr etc. and surrounding circuits, transformer, etc. this to achieve the 4ns (or 5ns). (the transformer I have in mind is something very similar to those transformers on the final stages of HF/VHF ham radio amps, coax cables and ferrite cores) any suggestion regarding devices etc ?... Thanks for all comments. Luis Cupido. ___ 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] Austron
Austron was purchased by Datum which was then purchased by Symmetricom, which was recently sold to Microsemi. Thomas Knox From: j...@westmorelandengineering.com Date: Thu, 26 Dec 2013 17:42:21 -0800 To: time-nuts@febo.com Subject: [time-nuts] Austron Hello Time-Nuts! I hope everyone is enjoying their Holiday Season! I have a question - I have been doing a little research lately on the company that used to be in Austin, TX - Austron - they seemed to have filed quite a few patents in areas of interest to our group. Here's one just as an example: https://www.google.com/patents/US5220333?pg=PA1dq=assignee:++austronhl=ensa=Xei=tdq8UoL_EqbQ2wXy14DwCAved=0CDcQ6AEwAA Are there any former Austron people on this list? If so, I would like to have a brief phone conversation with you if that is OK. Just general questions - nothing personal of course. E-Mail could work but could be quicker just to have a brief phone call. I have Skype also if that is easier. Thanks and Happy Holidays! John Westmoreland ___ 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] Austron
Hello Thomas, Yes - I was aware of that. And there is another company in there too I think - EndRun Technologies. Someone from that company told me about Austron. I am hoping someone on this list was employed by or worked for Austron. Thanks, John Westmoreland On Thu, Dec 26, 2013 at 10:41 PM, Tom Knox act...@hotmail.com wrote: Austron was purchased by Datum which was then purchased by Symmetricom, which was recently sold to Microsemi. Thomas Knox From: j...@westmorelandengineering.com Date: Thu, 26 Dec 2013 17:42:21 -0800 To: time-nuts@febo.com Subject: [time-nuts] Austron Hello Time-Nuts! I hope everyone is enjoying their Holiday Season! I have a question - I have been doing a little research lately on the company that used to be in Austin, TX - Austron - they seemed to have filed quite a few patents in areas of interest to our group. Here's one just as an example: https://www.google.com/patents/US5220333?pg=PA1dq=assignee:++austronhl=ensa=Xei=tdq8UoL_EqbQ2wXy14DwCAved=0CDcQ6AEwAA Are there any former Austron people on this list? If so, I would like to have a brief phone conversation with you if that is OK. Just general questions - nothing personal of course. E-Mail could work but could be quicker just to have a brief phone call. I have Skype also if that is easier. Thanks and Happy Holidays! John Westmoreland ___ 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.
