Re: [time-nuts] Time/freq from digital TV
Glenn: Please forgive a slight deviation from the time, but do you know what's happening to transmitters in the industry? Thanks very much Don Latham - Original Message - From: "Glenn Little WB4UIV" To: "Discussion of precise time and frequency measurement" Sent: Saturday, June 13, 2009 7:59 PM Subject: Re: [time-nuts] Time/freq from digital TV The digital transmitter could have a GPS based frequency reference. I am the CE for a local station (WCIV). We do not use any standard other than what is installed in the transmitter. I have not verified it, but, I think that the UHF transmitter frequency is controlled by an OCXO. I will try and remember to check on this Monday. I do know that our Analog transmitter used an ovenized crystal for frequency control. We were on channel 4. We definitely are not slaved to the network for frequency control. 73 Glenn WB4UIV At 06:18 PM 6/13/2009, you wrote: My radio has many news stories about the end of analog TV. What sort of time or frequency can I get from a digital TV signal? Now that frame buffers are common, does each station use its own master clock? -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] Hi!
Does anyone know where you can find a manual on the TRAK 8500 ? (Time Code Generator) 73, Dick, W1KSZ -Original Message- >From: Stanley Reynolds >Sent: Jun 13, 2009 10:11 PM >To: Discussion of precise time and frequency measurement >Subject: Re: [time-nuts] Hi! > > >For a commerical unit : http://www.febo.com/pages/hardware/PTS/ > >For a clock : http://www.qsl.net/zl1bpu/MICRO/CLOCK/index.htm (just the first >one I came to many more if you google) > >I have purchased some Time code generators abt $25 to $50 usd including >shipping on ebay that will take a external 10 Mhz look here : > >http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=220423640375 > >Stanley > > > >- Original Message >From: David Findlay >To: time-nuts@febo.com >Sent: Saturday, June 13, 2009 8:40:39 PM >Subject: [time-nuts] Hi! > >Hi my name is David and I have a rubidium standard. It's a Efratom 100334-006 >and outputs 10mhz. What can I do with it? > >As I understand it I need to provide it a reference to set it's frequency. I >was thinking it'd be cool to build a counter that counts the waves and is >thereby a clock. A master clock would be cool. Also a tunable highly accurate >frequency generator would be useful to me. Are there designs out there to >build homebrew equipment based on this, or should I just chase up something >commercial? Thanks, > >David > >___ >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] Thunderbolt UTC time offset
A quick search on Google finds (among many) this short article. http://www.seis.com.au/TechNotes/TN199901A_GPS_UTC.html - Original Message - From: "rtime @dslextreme.com" Date: Saturday, June 13, 2009 6:13 pm Subject: [time-nuts] Thunderbolt UTC time offset To: time-nuts@febo.com > Hi Everyone; > I have finally gotten around to getting my Thunderbolt > operational.Everything is working just fine but I do have a > question. In the Thunderbolt > monitor screen and the [Time] window I see that the time is 15 > seconds off > from my TAC and a little box tells me that the UTC Offset is set > to 15 > seconds. > Why would this offset exist and can I somehow reset it to zero? > Best regards, Bob K7HBG > > PS, Many thanks to Whomever it was that posted the > "Receiver Sensitivity " > 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. > ___ 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] Hi!
no space after link sorry linked fixed : http://www.qsl.net/zl1bpu/MICRO/CLOCK/index.htm and more abt the same : http://leapsecond.com/pages/atomic-nixie/ Stanley - Original Message From: David Findlay To: time-nuts@febo.com Sent: Saturday, June 13, 2009 8:40:39 PM Subject: [time-nuts] Hi! Hi my name is David and I have a rubidium standard. It's a Efratom 100334-006 and outputs 10mhz. What can I do with it? As I understand it I need to provide it a reference to set it's frequency. I was thinking it'd be cool to build a counter that counts the waves and is thereby a clock. A master clock would be cool. Also a tunable highly accurate frequency generator would be useful to me. Are there designs out there to build homebrew equipment based on this, or should I just chase up something commercial? Thanks, David ___ 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] Hi!
For a commerical unit : http://www.febo.com/pages/hardware/PTS/ For a clock : http://www.qsl.net/zl1bpu/MICRO/CLOCK/index.htm (just the first one I came to many more if you google) I have purchased some Time code generators abt $25 to $50 usd including shipping on ebay that will take a external 10 Mhz look here : http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=220423640375 Stanley - Original Message From: David Findlay To: time-nuts@febo.com Sent: Saturday, June 13, 2009 8:40:39 PM Subject: [time-nuts] Hi! Hi my name is David and I have a rubidium standard. It's a Efratom 100334-006 and outputs 10mhz. What can I do with it? As I understand it I need to provide it a reference to set it's frequency. I was thinking it'd be cool to build a counter that counts the waves and is thereby a clock. A master clock would be cool. Also a tunable highly accurate frequency generator would be useful to me. Are there designs out there to build homebrew equipment based on this, or should I just chase up something commercial? Thanks, David ___ 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] Time/freq from digital TV
On Sat, Jun 13, 2009 at 09:59:50PM -0400, Glenn Little WB4UIV wrote: > The digital transmitter could have a GPS based frequency reference. > I am the CE for a local station (WCIV). > We do not use any standard other than what is installed in the transmitter. > > I have not verified it, but, I think that the UHF transmitter > frequency is controlled by an OCXO. I'd bet a lot of current digital exciters use a digital synthesizer locked to a reference rather than a special OCXO crystal cut to a particular TV channel frequency. This COULD allow a 10 Mhz in lock to a GPSDO, rubidium or better... I found a couple of the Boston analog stations were very accurately on frequency using my spectrum analyzer signal counter with a 10 MHz GPSDO reference... so some folks somewhere must bother to lock signals. -- Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." ___ 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] DTV frequency reference signals...
Prior to change, DTV stations that had a first adjacent lower NTSC had to be within 3 Hz of a specific (5+ MHz) offset from that first adjacent lower NTSC's visual carrier in order to prevent interference to the NTSC's chroma. The only practical way to do that was for both stations to lock to GPS and each maintain, by gentlemen's agreement a 1.5 Hz tolerance. Some of the stations required to do this actually did it. In the Los Angeles area there were several that were stable and within 0.1 Hz. This is sufficient for checking or calibrating a service monitor in the field but not nearly tight enough for what we try to accomplish. The pilot signal is a 10 dB spike on the lower edge of the "box" as seen on a spectrum analyzer. Measuring this is like measuring any AM carrier. Now that NTSC analog is gone there is no requirement for anything other than the normal 1000 Hz tolerance of the pilot signal. Some stations may chose to lock or reference to a GPS standard but this is not a requirement. As to what signals may be within the data channel, I have no idea what's there other than a lot of boring programming. Burt, K6OQK From: Hal Murray Subject: [time-nuts] Time/freq from digital TV My radio has many news stories about the end of analog TV. What sort of time or frequency can I get from a digital TV signal? Now that frame buffers are common, does each station use its own master clock? Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net K6OQK ___ 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] Time/freq from digital TV
The digital transmitter could have a GPS based frequency reference. I am the CE for a local station (WCIV). We do not use any standard other than what is installed in the transmitter. I have not verified it, but, I think that the UHF transmitter frequency is controlled by an OCXO. I will try and remember to check on this Monday. I do know that our Analog transmitter used an ovenized crystal for frequency control. We were on channel 4. We definitely are not slaved to the network for frequency control. 73 Glenn WB4UIV At 06:18 PM 6/13/2009, you wrote: My radio has many news stories about the end of analog TV. What sort of time or frequency can I get from a digital TV signal? Now that frame buffers are common, does each station use its own master clock? -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] Time/freq from digital TV
On Sat, Jun 13, 2009 at 03:18:16PM -0700, Hal Murray wrote: > > My radio has many news stories about the end of analog TV. > > What sort of time or frequency can I get from a digital TV signal? > > Now that frame buffers are common, does each station use its own master clock? I don't believe there is any standards grade time or frequency that one can derive from a FCC legal standards conformant ATSC transmission in digital format. There are fairly loose specs for ATSC symbol rate (by time-nuts standards) and carrier frequency - not dead nuts on in any broadcast plant unless someone engineering it really cared for some reason. And nothing in the ATSC stream establishes a precise epoch - the stream consists of 188 byte transport stream packets... sent from a queue when a time slot is available... with no particular discipline that a particular packet be sent at a particular exact time. There is, however, a timing mechanism in MPEG2 TV based on a 27 MHz clock that controls and coordinates video and audio rendering in digital TVs ... and part of this is that some packets carry a timestamp in ticks of this clock (called the PCR) so a receiver can lock its own 27 MHz video timebase to this clock so video frames and audio samples are output at the correct times - mostly relative to each other and the video source, of course, and not any absolute UTC time. Broadcast plant may or may not lock its master 27 MHz PCR reference to a GPSDO or rubidium - there is no requirement to do so. And no particular expectation that some epoch of the PCR clock matches a particular UTC epoch. Likely the choice is to use the OCXO in a house master sync generator or ATSC multiplexer as the reference or use an external clock input from some kind of frequency standard. I suppose there ARE stations that use a decent GPSDO or other high grade frequency source for this... how one knows this is true in any particular case, however, is not clear. Most network broadcast distribution is via satellite, and satellites move around in their box in the sky so any time or frequency derived from satellite downlinked signals is subject to Doppler shifts over the course of a day as the satellite completes its figure eight pattern in the sky (most operational birds are slightly inclined, thus the figure 8 - none are dead nuts on the equator and in perfectly circular orbits). This means that no network timing from a satellite signal is stable by precise metric standards... even if the uplink signal is right on. What all this means in practice is that there is no longer any precise broadcast TV signal that can be depended on as really accurate. Of course this has already been true for at least the past 20 years with analog NTSC transmissions from ubiquitous digital broadcast plant... for the most part the timing for the old analog NTSC transmissions was derived from the OCXO (or even just TCXO) in either a master sync generator or the digital NTSC modulator just before the transmitter modulator analog input... long long gone are the 1970s era days of a completely analog and un frame buffered path between a stable analog terrestrial microwave based link to a master rubidium or cesium network clock in NYC and the input to the transmitter... -- Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." ___ 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] Hi!
Hi my name is David and I have a rubidium standard. It's a Efratom 100334-006 and outputs 10mhz. What can I do with it? As I understand it I need to provide it a reference to set it's frequency. I was thinking it'd be cool to build a counter that counts the waves and is thereby a clock. A master clock would be cool. Also a tunable highly accurate frequency generator would be useful to me. Are there designs out there to build homebrew equipment based on this, or should I just chase up something commercial? Thanks, David ___ 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] Thunderbolt UTC time offset
Hi Everyone; I have finally gotten around to getting my Thunderbolt operational. Everything is working just fine but I do have a question. In the Thunderbolt monitor screen and the [Time] window I see that the time is 15 seconds off from my TAC and a little box tells me that the UTC Offset is set to 15 seconds. Why would this offset exist and can I somehow reset it to zero? Best regards, Bob K7HBG PS, Many thanks to Whomever it was that posted the "Receiver Sensitivity " 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.
[time-nuts] Time/freq from digital TV
My radio has many news stories about the end of analog TV. What sort of time or frequency can I get from a digital TV signal? Now that frame buffers are common, does each station use its own master clock? -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt stability and ambient temperature
Hi, Water must have a fairly high figure of merit for thermal buffering. Unfortunately the lists of material properties are inaccurate, have gross errors and are inevitably listed in units such as tons per Degree F per inch per square foot. The tons refer to tons of ice per 24 hours, a good old reliable air condtioning unit. The relevant measures are thermal conductivity, thermal heat capacity, density and thermal diffusivity. Now there is an interesting comparison between copper and aluminium. Copper has a specific heat of 0.09 and aluminium 0.2. (cal/gm C ) Copper has a relative thermal conductivity of 0.918 and aluminium 0.48 Copper has a density of 8.9 and Al 2.7 So the heat capacity of copper is 0.8 and Al 0.54 cal/C/cc when calculated on a volume basis. So water at 1cal/C/cc is better than copper, and twice as good as Aluminium. Where water really wins is on price, and being a liquid it will heat with convective circulation and so be much faster than the solids to reach equilibrium. cheers, Neville Michie On 14/06/2009, at 4:14 AM, Chuck Harris wrote: Yes, but if it takes 20 years for 1 tsp of water to be lost, I just don't see how that rules out the use of water as a thermal ballast. Water's cheapness and availability in bulk makes it quite attractive for this purpose. If you don't trust plastic, use copper, or stainless steel, or... If man can keep a vacuum in a vacuum tube for 100 years, surely keeping a little water in a bottle or can isn't that hard? Besides, I don't think we were talking about putting the water inside of a crystal oven. We were talking about using water as a thermal ballast to keep the closet/box your standard occupied at a more stable temperature. -Chuck Harris J. Forster wrote: Chuck, I don't dispute that you can contain water in plastic a long time, but, if some does escape it may not matter to the bottle contents, but it could well raise the humidity of the surround w/in a tightly sealed oven/box/enclosure. Electronics does not much like high humidity. -John ___ 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] Thunderbolt stability and ambient temperature
On 6/13/09 10:16 AM, "Thomas A. Frank" wrote:
>>> I just don't know what to say to that! Even a child can put a
>>> case of bottled water in a box, and not have it evaporate or leak.
>>> I would venture that said case of bottled water will still be full
>>> up when the child graduates from college, and has kids of his own.
>>
>> But goodness knows what sort of a biological hazard it will be by
>> then :-)
>
>
> More to the point, you will be disappointed to find the bottles will
> NOT last that long.
See.. The traditional port in glass bottles will survive for decades, if not
centuries. If you're going to get thermal mass for your reference
oscillator, and you're going to seal it up a'la the "Cask of Amontillado",
at least use something that benefits from the age. Plastic bottle of
processed tap water isn't it. {N.B. Amontillado is Sherry, not Port, but
same basic idea, same benefit from age; and no, I do not recommend sealing a
time-nut in the same area. They get cranky and inefficient.}
>
>
___
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] Thunderbolt stability and ambient temperature
Yes, but if it takes 20 years for 1 tsp of water to be lost, I just don't see how that rules out the use of water as a thermal ballast. Water's cheapness and availability in bulk makes it quite attractive for this purpose. If you don't trust plastic, use copper, or stainless steel, or... If man can keep a vacuum in a vacuum tube for 100 years, surely keeping a little water in a bottle or can isn't that hard? Besides, I don't think we were talking about putting the water inside of a crystal oven. We were talking about using water as a thermal ballast to keep the closet/box your standard occupied at a more stable temperature. -Chuck Harris J. Forster wrote: Chuck, I don't dispute that you can contain water in plastic a long time, but, if some does escape it may not matter to the bottle contents, but it could well raise the humidity of the surround w/in a tightly sealed oven/box/enclosure. Electronics does not much like high humidity. -John ___ 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] Thunderbolt stability and ambient temperature
Chuck, I don't dispute that you can contain water in plastic a long time, but, if some does escape it may not matter to the bottle contents, but it could well raise the humidity of the surround w/in a tightly sealed oven/box/enclosure. Electronics does not much like high humidity. -John === > Sigh! I guess the point is still being missed. It isn't hard at > all to keep water in a container. The plastic water bottle scenario > was created to put the issue into perspective. Perhaps some plastic > bottles don't have the staying power to last into the next century, > but that doesn't in any way indicate that it is a difficult problem. > > There are metal cans that have held liquids for centuries. There > are glass, and ceramic bottles that have held liquids for thousands > of years. > > Surely if you wanted to use a quantity of water to act as a thermal > ballast, or cushion, it would be worth the tiny amount of effort > necessary to enclose it? Perhaps something glued up out of Schedule > 40 PVC pipe? Or maybe a Nalgene bottle? Or a thick walled LDPE > bottle? Even a concrete tank wouldn't be out of the question if > you needed a big enough ballast. There are concrete basins that > have been holding water for decades. > > Don't let the fact that water might leak dissuade you from using > it as a cheap highly capable thermal ballast. > > -Chuck Harris > > Thomas A. Frank wrote: > >> More to the point, you will be disappointed to find the bottles will NOT >> last that long. >> >> Cleaning out the cupboard recently, I can across some bottled water that >> had 1998 date codes. Several had leaked, but one was still intact >> enough to show the likely problem. It would appear that over the past >> 10 years, the gases dissolved in the water migrated through the plastic >> (or the cap seal), resulting in a vacuum forming in the bottle. This >> distended the bottles and caused structural failure. >> >> Either that, or the water caused the plastic to shrink. >> >> Glass would probably fair better. >> >> Tom Frank, KA2CDK > > ___ > 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] Thunderbolt stability and ambient temperature
Sigh! I guess the point is still being missed. It isn't hard at all to keep water in a container. The plastic water bottle scenario was created to put the issue into perspective. Perhaps some plastic bottles don't have the staying power to last into the next century, but that doesn't in any way indicate that it is a difficult problem. There are metal cans that have held liquids for centuries. There are glass, and ceramic bottles that have held liquids for thousands of years. Surely if you wanted to use a quantity of water to act as a thermal ballast, or cushion, it would be worth the tiny amount of effort necessary to enclose it? Perhaps something glued up out of Schedule 40 PVC pipe? Or maybe a Nalgene bottle? Or a thick walled LDPE bottle? Even a concrete tank wouldn't be out of the question if you needed a big enough ballast. There are concrete basins that have been holding water for decades. Don't let the fact that water might leak dissuade you from using it as a cheap highly capable thermal ballast. -Chuck Harris Thomas A. Frank wrote: More to the point, you will be disappointed to find the bottles will NOT last that long. Cleaning out the cupboard recently, I can across some bottled water that had 1998 date codes. Several had leaked, but one was still intact enough to show the likely problem. It would appear that over the past 10 years, the gases dissolved in the water migrated through the plastic (or the cap seal), resulting in a vacuum forming in the bottle. This distended the bottles and caused structural failure. Either that, or the water caused the plastic to shrink. Glass would probably fair better. Tom Frank, KA2CDK ___ 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] Thunderbolt stability and ambient temperature
I just don't know what to say to that! Even a child can put a case of bottled water in a box, and not have it evaporate or leak. I would venture that said case of bottled water will still be full up when the child graduates from college, and has kids of his own. But goodness knows what sort of a biological hazard it will be by then :-) More to the point, you will be disappointed to find the bottles will NOT last that long. Cleaning out the cupboard recently, I can across some bottled water that had 1998 date codes. Several had leaked, but one was still intact enough to show the likely problem. It would appear that over the past 10 years, the gases dissolved in the water migrated through the plastic (or the cap seal), resulting in a vacuum forming in the bottle. This distended the bottles and caused structural failure. Either that, or the water caused the plastic to shrink. Glass would probably fair better. Tom Frank, KA2CDK ___ 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] Thunderbolt stability and ambient temperature
Hi Rex, I just did something similar. I was doing some heavy grinding on a 6 inch long rod that was to become a new tool, and as I started to perceive that the rod was getting hot, I dunked the end I was grinding into cool water. And, I almost immediately started to feel the rod, where I was gripping it, cooling down. I am certain that you were just moments away from feeling the heat reach your grip when you decided to cool the rod you were working. It would have gotten to your hand at the same time whether or not you had decided to plunge the rod into water. Even though I don't recall hearing anyone make the same claim as you have, I do have a couple of books on blacksmithing, from the days of yore, that I will skim to see if anyone observed the same effect. -Chuck Harris Rex wrote: Chuck Harris wrote: I truly hope you aren't bothered by our rumination. We clearly are enjoying the subject. Thanks for bringing it up. -Chuck Harris No, not at all. I brought it up because what I think I saw doesn't make sense from anything I know. I already have a large list of partially-done projects, so I doubt if I'll get back to another look at this subject soon. If I ever do I'll try to post any results. -Rex ___ 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] E1938 PIC hex files?
Pics have pretty good copy protection. I'd be surprised if Agilent haven't protected the pic in the E1938. Many pics (AFIK thisincludes the 'C74) scramble the data on reading a copy protected chip. This allows the verification of a chip without revealing the code. A known good chip is a starting point. fortuntly HP socketed the PLCC pic. Know you need a time nut with a good E1938, a PicStart Plus ( or similar programmer) and a PLCC adaptor. I have the latter two but no E1938. Robert G8RPI. --- On Sat, 13/6/09, Richard H McCorkle wrote: > From: Richard H McCorkle > Subject: Re: [time-nuts] E1938 PIC hex files? > To: dan...@verizon.net, "Discussion of precise time and frequency > measurement" > Date: Saturday, 13 June, 2009, 7:16 AM > Hi Dan, > > If the 1938 was purchased through Fluke1 he is usually very > good > about replacing bad items he sells to Time-Nuts. You might > want > to contact him about a replacement unit or perhaps getting > a > pre-programmed PIC from a different unit to try. > > Richard > > > > I am beginning to think that the PIC in my Chinese > Ebay 1938 is dead or > > at least injured. Does anyone have the hex files > for this one? Blank > > PIC16C74As can be had and it may be worth my trying to > program a new > > one. Nothing else seems to make it work and as > the PIC seems to be > > asleep, I'm not sure that attempting to talk to it > with the serial > > program is going to help me much, but I will try. > > > > The part number is: E1938-80002 > > > > > > Dan > > > > ac6ao > > > > > > > > ___ > > 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.
