[time-nuts] Is this DOCXO an SC or AT cut rock?
I'm curious if an OCXO has an SC or AT cut crystal in it. There's no EFC, so I can't measure sensitivity. I did measure the frequency change from cold startup, thinking that an SC cut would stabilize quicker than an AT. I don't have a good AT OCXO to compare against, but I do have a Morion MV89A (should be an SC, right?). Graphs: http://n5tnl.com/time/mv89a/mv89a.png http://n5tnl.com/time/mv89a/unknown.png Thoughts? The two units are the same size and shape. The Morion ran without the outer can. Measurement note: my 5370A is sick, and my 5345A doesn't do GPIB. So I shot video with the counter (1 s gate time, using a tbolt as the 10 MHz ref) and meter (measuring current) in the frame. From there, I used vlc to spit out still images at about 1 Hz, then imagemagick to cut out the sections with the seven segment displays. ssocr (http://www.unix-ag.uni-kl.de/~auerswal/ssocr/) did the real magic of converting the seven segment displays in the images to text. Had to do some hand cleanup on a few data points, but it was a lot less frustrating than typing in thousands of data points by hand. I'm sure it'd work better with a more careful layout and lighting. -- newell N5TNL ___ 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] Is this DOCXO an SC or AT cut rock?
Scott, On 08/10/2014 08:54 AM, Scott Newell wrote: I'm curious if an OCXO has an SC or AT cut crystal in it. There's no EFC, so I can't measure sensitivity. I did measure the frequency change from cold startup, thinking that an SC cut would stabilize quicker than an AT. I don't have a good AT OCXO to compare against, but I do have a Morion MV89A (should be an SC, right?). Graphs: http://n5tnl.com/time/mv89a/mv89a.png http://n5tnl.com/time/mv89a/unknown.png Thoughts? The two units are the same size and shape. The Morion ran without the outer can. Sure looks like a SC cut oscillator. We did this exercise many years ago, and if you dig the archives you can find the numbers for AT, BT and SC cut oscillators. AT cut was in the -145 ppm range as I remember while SC is -20-25 ppm off. Good that you made the cold-start measurement! Extra points for measuring currents. Interesting to see the shut-off ringing. War-story: I was testing one oven oscillator which looked nice on paper. Measuring it I saw a bump in the ADEV at 7 s, and looking at the frequency phase plots I saw the wobble. Hooking up a DMM I can barely see the wobble. As I power-cycled the oven, I see the same wobble already from power-up. Turns out that the oven controller has a very high Q value and is ringing and that the ringing never really dies out. The vendor had transfered a design to a new board, so the oven was sitting on a ceramic board rather than a FR-4 board inside the can. FR-4 has much more thermal mass so it kept the loop nice and stable, but not the re-tuned oscillator. Measurement note: my 5370A is sick, and my 5345A doesn't do GPIB. So I shot video with the counter (1 s gate time, using a tbolt as the 10 MHz ref) and meter (measuring current) in the frame. From there, I used vlc to spit out still images at about 1 Hz, then imagemagick to cut out the sections with the seven segment displays. ssocr (http://www.unix-ag.uni-kl.de/~auerswal/ssocr/) did the real magic of converting the seven segment displays in the images to text. Had to do some hand cleanup on a few data points, but it was a lot less frustrating than typing in thousands of data points by hand. I'm sure it'd work better with a more careful layout and lighting. Messy, but it works. Hope you find a smoother measuring path soon. Sure would like if TimeLab could log current and temperature too. 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] WWVB for Time Nuts
On 10 Aug 2014 05:39, Jim Lux jim...@earthlink.net wrote: (but, I gotta say that a lot of the patents that get published in the back of things like IEEE Ant and Prop Magazine seem, to me, to be pretty obvious..) I have not looked at patents recently, but most I have looked in the past are fairly obvious to someone skilled in that area. Another large group appears to be useless things. Perhaps time-nuts should stick on a web site a list of 100 obvious things that they believe someone might just try to patent. Once an idea is disclosed like that, it should stop a patent being issued. Perhaps a braille clock with an internal atomic frequency reference. I don't suppose anyone has made one, as the demand would be low, but it is in my a opinion fairly obvious approach for a skilled person. I assume there is some time delay (probably in the range 100 us to 10s) between one observing a clock and one's brain decoding it. So for a person to believe that they know the time, the clock actually has to display it a bit fast. But more seriously, one could probably have some impact on time nut related patents by documenting semi obvious things on a web site in advance. I recall being at the patent office in London and see someone had a patent on a screen built into a microwave oven hooked upto a video camera so you could check on the security of your premises while cooking. I guess with China pretty much ignoring patents, it might become more attractive to keep something a trade secret rather than patent it. I believe Samsung and Apple have recently agreed to drop patent infringement cases against each other outside the USA http://www.forbes.com/sites/amitchowdhry/2014/08/06/apple-and-samsung-drop-patent-disputes-against-each-other-outside-of-the-u-s/ I know BT and Marconi did a similar thing, as I guess that they realised that they were spending an excessive amount of money fighting each other over patent infringement. 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] Lamp for FRK Rubidium Needed
Chuck Harris cfharris@... writes: Paul's description is spot on. Once the bulb is clear, you are done. The real truth is once it is clearer than it was, it is going to work better than it did... When it is all the way clear, it is a good as it was when it was new, and should last as long as a new bulb would have. -Chuck Harris Peter wrote: paul swed paulswedb at ... writes: Chuck is correct I have done this trick on FRS units. The glass clears and the lamp re-ignites and continues to work for a long time. Actually it hasn't failed and this must be 2 years now. Regards Paul WB8TSL Thanks to the help from members here I now have a locking FRK. My bulb looked pretty clear, and i couldnt find any deposits or bits inside, but decided to give it a good soaking at about 150 deg C using my hot air re-work gun for about 10 mins. I have checked it against my Racal ovened reference and found a discrepancy of about 0.8 Hz. Now the million dollar question...Can I be sure the FRK is good before I start to use it as my standard frequency? Is the FRK constructed in such a way that the frequency accuracy is assured, or do I need some way of verifying the FRK, or calibrating it. I dont want to trim my ovened reference to the rubidium, only to find the rubidium is not as accurate as I thought? Sorry if dumb questions, but just starting my quest for time nut status!!! Thanks Peter G0RSQ ___ 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] VLF Phase-tracking receivers.
On iPhone Yes but those stations are fsk so the offsets an issue We may assume the transmitter is accurate But how accurate? Then the fsk generator On Saturday, August 9, 2014, Kenneth G. Gordon kgordon2...@frontier.com wrote: On 9 Aug 2014 at 19:17, paul swed wrote: Ken All of the phase tracking receivers no longer work due to the new bpsk wwvb modulation. Hello, Paul. Yes. I knew that WWVB had switched to BPSK, but these receivers were specifically designed to tune to any of the VLF stations between 3 and 99.95 KHz. They used NAA, NPG, and GBR as examples. Certainly if you need accuracy any of the GPSDOs out there are better then the old wwvb receivers. Well, I wasn't thinking so much of accuracy as simply watching the servos hunt. ;-) I have a 599 and will hope that the project I have been working on for far to long will allow it to track again. Supposedly, it would track any of the VLF stations which transmitted phase-stable signals, even those which used FSK or its equivalent. As to the 1310s etc. Never heard of them. Something to search for on the internet. Regards Paul WB8TSL Well, I have done just that. I found two references to those: one was from a Canadian university project which was trying to use Phase-Tracking receivers to track the position of an ice-island. They were trying to use both an RMS Engineering 1312, and two Tracor 599s. Due to errors in their attempts to use the equipment with which they weren't familiar, they didn't have much luck. The other reference was to an exchange on this very forum back in 2010...I think. Someone said they had been using a 1312 for 20 years. Anyway, thanks for the help. Much appreciated. Ken W7EKB ___ 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] WWVB for Time Nuts
There's a really good article on patents and the notional person skilled in the art at: http://www.inhouselawyer.co.uk/index.php/intellectual-property/9902-pate nts-and-the-notional-person-skilled-in-the-art If your mailer splits lines for you, you'll have to copy and paste the rest of the link. Note that the author is in the UK, not the US. There are at least two uses for the notional person: 1. Define the prior art with respect to the patent 2. Be able to understand the patent as it is written. Then there's the great long list of what is claimed, going from very general to very specific. This is done so that something will remain if the general claims are not accepted by the examiner. Disclaimer: I have a couple of patents, but I am not any kind of lawyer. Bill Hawkins -Original Message- From: Jim Lux Sent: Saturday, August 09, 2014 11:39 PM On 8/9/14, 9:36 PM, Lee Mushel wrote: Jeeze, Brooke, I wish you hadn't brought up the possible patenting of Time Delay Beam steering antennas! I wonder if my highly esteemed SDR radio which I think uses some such technology, is illegal? long since expired.. (but, I gotta say that a lot of the patents that get published in the back of things like IEEE Ant and Prop Magazine seem, to me, to be pretty obvious..) ___ 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] Lamp for FRK Rubidium Needed
Le 10 août 2014 à 12:01, Peter a écrit : I have checked it against my Racal ovened reference and found a discrepancy of about 0.8 Hz. Now the million dollar question...Can I be sure the FRK is good before I start to use it as my standard frequency? Is the FRK constructed in such a way that the frequency accuracy is assured, or do I need some way of verifying the FRK, or calibrating it. I dont want to trim my ovened reference to the rubidium, only to find the rubidium is not as accurate as I thought? Sorry if dumb questions, but just starting my quest for time nut status!!! Ahhh ! A man with two clocks. Not much help I am afraid , but you need a better ref. Thanks Peter G0RSQ ___ 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] Lamp for FRK Rubidium Needed
Hi, If I am understanding you correctly, you seem to think that a rubidium cell standard is a primary reference? The rubidium cell standard is not a primary reference. Before you use it as a reference, you need to compare/calibrate it to a primary standard, such as a cesium beam. Then, like a quartz crystal, you can adjust your rubidium to the primary standard. -Chuck Harris Peter wrote: Chuck Harris cfharris@... writes: Paul's description is spot on. Once the bulb is clear, you are done. The real truth is once it is clearer than it was, it is going to work better than it did... When it is all the way clear, it is a good as it was when it was new, and should last as long as a new bulb would have. -Chuck Harris Peter wrote: paul swed paulswedb at ... writes: Chuck is correct I have done this trick on FRS units. The glass clears and the lamp re-ignites and continues to work for a long time. Actually it hasn't failed and this must be 2 years now. Regards Paul WB8TSL Thanks to the help from members here I now have a locking FRK. My bulb looked pretty clear, and i couldnt find any deposits or bits inside, but decided to give it a good soaking at about 150 deg C using my hot air re-work gun for about 10 mins. I have checked it against my Racal ovened reference and found a discrepancy of about 0.8 Hz. Now the million dollar question...Can I be sure the FRK is good before I start to use it as my standard frequency? Is the FRK constructed in such a way that the frequency accuracy is assured, or do I need some way of verifying the FRK, or calibrating it. I dont want to trim my ovened reference to the rubidium, only to find the rubidium is not as accurate as I thought? Sorry if dumb questions, but just starting my quest for time nut status!!! Thanks Peter G0RSQ ___ 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] WWVB for Time Nuts
Hi Keep in mind that it’s relatively cheap (big company wise) to get a patent. It’s only got major value once the courts uphold it as valid. That process costs real money. I’ve seen a variety of estimates on how many patents get issued that would never stand up to challenge. None of the estimates I’ve seen have been below 50%, some are a lot higher. Since the patents for sunscreen that’s only useful on the moon also get tossed into some of the estimates, who knows what the real numbers are. Often the protection process becomes a “we have 689 patents on this gizmo” sort of thing. Even if 99% of them are bunk, it will cost you a lot to prove that. You still would have to pay based on the 1% that turn out to be valid. The net result is a system that never challenges (and clears out) the junk. Bob On Aug 10, 2014, at 4:24 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: On 10 Aug 2014 05:39, Jim Lux jim...@earthlink.net wrote: (but, I gotta say that a lot of the patents that get published in the back of things like IEEE Ant and Prop Magazine seem, to me, to be pretty obvious..) I have not looked at patents recently, but most I have looked in the past are fairly obvious to someone skilled in that area. Another large group appears to be useless things. Perhaps time-nuts should stick on a web site a list of 100 obvious things that they believe someone might just try to patent. Once an idea is disclosed like that, it should stop a patent being issued. Perhaps a braille clock with an internal atomic frequency reference. I don't suppose anyone has made one, as the demand would be low, but it is in my a opinion fairly obvious approach for a skilled person. I assume there is some time delay (probably in the range 100 us to 10s) between one observing a clock and one's brain decoding it. So for a person to believe that they know the time, the clock actually has to display it a bit fast. But more seriously, one could probably have some impact on time nut related patents by documenting semi obvious things on a web site in advance. I recall being at the patent office in London and see someone had a patent on a screen built into a microwave oven hooked upto a video camera so you could check on the security of your premises while cooking. I guess with China pretty much ignoring patents, it might become more attractive to keep something a trade secret rather than patent it. I believe Samsung and Apple have recently agreed to drop patent infringement cases against each other outside the USA http://www.forbes.com/sites/amitchowdhry/2014/08/06/apple-and-samsung-drop-patent-disputes-against-each-other-outside-of-the-u-s/ I know BT and Marconi did a similar thing, as I guess that they realised that they were spending an excessive amount of money fighting each other over patent infringement. 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] Lamp for FRK Rubidium Needed
Hi Simple answer - you need something to compare it to. Longer answer - Rubidium is a secondary frequency standard. A variety of things can pull it off frequency. One of the issues in FRK style Rb production is the number of lamps that get made to far off frequency to be useful. Easy solutions: 1) Beg / borrow / steal a GPSDO for a week or two. 2) Divide down and compare against WWV time ticks for about 12 days per observation. 3) Visit a friend with a working Cesium standard. 4) Get a $17 eBay GPS and compare for a week or so. Yes there are many other possible approaches. Some of the above assumes you have a fairly good dual channel scope. Math on the WWV time tick: There are a bit over a million seconds in 12 days (1036800). If you measure to one second, you get a ppm. If you can resolve to 1 ms (~1/2 cycle on the tick) you are at 1 ppb. Your Rb should warm up for at least a week before you tweak it. You should confirm any adjustment for at least a week after you do it. A 12 day measurement process isn’t all that crazy in this case. Bob On Aug 10, 2014, at 6:01 AM, Peter pe...@g0rsq.co.uk wrote: Chuck Harris cfharris@... writes: Paul's description is spot on. Once the bulb is clear, you are done. The real truth is once it is clearer than it was, it is going to work better than it did... When it is all the way clear, it is a good as it was when it was new, and should last as long as a new bulb would have. -Chuck Harris Peter wrote: paul swed paulswedb at ... writes: Chuck is correct I have done this trick on FRS units. The glass clears and the lamp re-ignites and continues to work for a long time. Actually it hasn't failed and this must be 2 years now. Regards Paul WB8TSL Thanks to the help from members here I now have a locking FRK. My bulb looked pretty clear, and i couldnt find any deposits or bits inside, but decided to give it a good soaking at about 150 deg C using my hot air re-work gun for about 10 mins. I have checked it against my Racal ovened reference and found a discrepancy of about 0.8 Hz. Now the million dollar question...Can I be sure the FRK is good before I start to use it as my standard frequency? Is the FRK constructed in such a way that the frequency accuracy is assured, or do I need some way of verifying the FRK, or calibrating it. I dont want to trim my ovened reference to the rubidium, only to find the rubidium is not as accurate as I thought? Sorry if dumb questions, but just starting my quest for time nut status!!! Thanks Peter G0RSQ ___ 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] WWVB for Time Nuts
On 8/10/14, 5:41 AM, Bob Camp wrote: Hi Keep in mind that it’s relatively cheap (big company wise) to get a patent. It’s only got major value once the courts uphold it as valid. That process costs real money. I’ve seen a variety of estimates on how many patents get issued that would never stand up to challenge. None of the estimates I’ve seen have been below 50%, some are a lot higher. Since the patents for sunscreen that’s only useful on the moon also get tossed into some of the estimates, who knows what the real numbers are. Often the protection process becomes a “we have 689 patents on this gizmo” sort of thing. Even if 99% of them are bunk, it will cost you a lot to prove that. You still would have to pay based on the 1% that turn out to be valid. The net result is a system that never challenges (and clears out) the junk. Or, we have 689 patents and you have 325 patents, so let's cross license our pools ___ 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] WWVB for Time Nuts
Hi, How does patent infringement litigation get started anyway? I would think that the infringement claim would have to be specific i.e. you are infringing on our patent number blah, claims blah, blah, blah blah. not just you are infringing on our patent. you need to halt production immediately and can't resume until you have properly guessed how you are infringing and stop, or, pay us a crapload of money. AFAICT, the patent includes no claims regarding conventional BPSK detection and demodulation. The patent seems to be about arranging the bits in a 'more efficient' way that, when taken advantage of by the receiver described in the patent, makes possible a 20dB process gain over a conventional AM envelope receiver. I am having a difficult time imagining a conventional receiver design (even one implemented in DSP) that would infringe on this patent. In at least one of their papers they even contrasted their receiver architecture to a conventional BPSK receiver. All that being said, I suspect that there is no real market for a WWVB based timing product. Even before the modulation change there were no commercial WWVB based timing products, and there hadn't been in several years. So, If you want to buck the trend and make such a product, You can probably do so without much fear of someone coming after you. I suspect though that 5 years hence you will be able to hold your equipment users group meetings in a room the size of a broom closet. And that’s assuming you are still using yours! Dale -Original Message- From: Bob Camp Sent: Sunday, August 10, 2014 8:41 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] WWVB for Time Nuts Hi Keep in mind that it’s relatively cheap (big company wise) to get a patent. It’s only got major value once the courts uphold it as valid. That process costs real money. I’ve seen a variety of estimates on how many patents get issued that would never stand up to challenge. None of the estimates I’ve seen have been below 50%, some are a lot higher. Since the patents for sunscreen that’s only useful on the moon also get tossed into some of the estimates, who knows what the real numbers are. Often the protection process becomes a “we have 689 patents on this gizmo” sort of thing. Even if 99% of them are bunk, it will cost you a lot to prove that. You still would have to pay based on the 1% that turn out to be valid. The net result is a system that never challenges (and clears out) the junk. Bob On Aug 10, 2014, at 4:24 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: On 10 Aug 2014 05:39, Jim Lux jim...@earthlink.net wrote: (but, I gotta say that a lot of the patents that get published in the back of things like IEEE Ant and Prop Magazine seem, to me, to be pretty obvious..) I have not looked at patents recently, but most I have looked in the past are fairly obvious to someone skilled in that area. Another large group appears to be useless things. Perhaps time-nuts should stick on a web site a list of 100 obvious things that they believe someone might just try to patent. Once an idea is disclosed like that, it should stop a patent being issued. Perhaps a braille clock with an internal atomic frequency reference. I don't suppose anyone has made one, as the demand would be low, but it is in my a opinion fairly obvious approach for a skilled person. I assume there is some time delay (probably in the range 100 us to 10s) between one observing a clock and one's brain decoding it. So for a person to believe that they know the time, the clock actually has to display it a bit fast. But more seriously, one could probably have some impact on time nut related patents by documenting semi obvious things on a web site in advance. I recall being at the patent office in London and see someone had a patent on a screen built into a microwave oven hooked upto a video camera so you could check on the security of your premises while cooking. I guess with China pretty much ignoring patents, it might become more attractive to keep something a trade secret rather than patent it. I believe Samsung and Apple have recently agreed to drop patent infringement cases against each other outside the USA http://www.forbes.com/sites/amitchowdhry/2014/08/06/apple-and-samsung-drop-patent-disputes-against-each-other-outside-of-the-u-s/ I know BT and Marconi did a similar thing, as I guess that they realised that they were spending an excessive amount of money fighting each other over patent infringement. 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
Re: [time-nuts] WWVB for Time Nuts
Hi …. which also eliminates a full examination and challenge. Bottom line as I still see it - For Time Nuts one off / home use / zero profit/ personal experimentation, I would not worry about the patents that are or are not present on the receiver for the WWVB format. I would not go out and start selling a product without some sort of protection. In that case if they want 10% of my (likely zero) profits, that’s not going to stop me. The same would be true if they are after 1% of my gross (one percent of $10 programmed uP’s times 100 pieces isn’t much). The killer would be some sort of flat license fee dimensioned in kilobucks. Until they come up with details there’s no real way to know how much of an issue this would be, even for a hobby project. They have 5 years of protection on this, and the clock has been running for at least a year, maybe more. At the rate this is going, there might not even be a chip before the 5 years runs out. Bob On Aug 10, 2014, at 11:01 AM, Jim Lux jim...@earthlink.net wrote: On 8/10/14, 5:41 AM, Bob Camp wrote: Hi Keep in mind that it’s relatively cheap (big company wise) to get a patent. It’s only got major value once the courts uphold it as valid. That process costs real money. I’ve seen a variety of estimates on how many patents get issued that would never stand up to challenge. None of the estimates I’ve seen have been below 50%, some are a lot higher. Since the patents for sunscreen that’s only useful on the moon also get tossed into some of the estimates, who knows what the real numbers are. Often the protection process becomes a “we have 689 patents on this gizmo” sort of thing. Even if 99% of them are bunk, it will cost you a lot to prove that. You still would have to pay based on the 1% that turn out to be valid. The net result is a system that never challenges (and clears out) the junk. Or, we have 689 patents and you have 325 patents, so let's cross license our pools ___ 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] WWVB for Time Nuts
Hi The entire commercial use case for timing grade WWVB (and Loran) comes from GPS denial of service. As time goes by, that becomes a more often discussed topic. We have gone over it several times in the past year. From what I’ve seen, this list is far more aware of the issues than any commercial user organization out there. I’d guess that military organizations may be a bit more aware than the commercial guys. For them WWVB is not a solution. This being Time Nuts, there is always an interest in extracting time data from anything you can get ahold of. I think that the discussion of the impact of any patents on a group project in this area is indeed very relevant. I believe that the demodulation of the bit stream can be done by obvious techniques. Since I’m not a lawyer that belief may not be worth much. Again making it worth digging into this a bit deeper. Bob On Aug 10, 2014, at 11:14 AM, Dale J. Robertson d...@nap-us.com wrote: Hi, How does patent infringement litigation get started anyway? I would think that the infringement claim would have to be specific i.e. you are infringing on our patent number blah, claims blah, blah, blah blah. not just you are infringing on our patent. you need to halt production immediately and can't resume until you have properly guessed how you are infringing and stop, or, pay us a crapload of money. AFAICT, the patent includes no claims regarding conventional BPSK detection and demodulation. The patent seems to be about arranging the bits in a 'more efficient' way that, when taken advantage of by the receiver described in the patent, makes possible a 20dB process gain over a conventional AM envelope receiver. I am having a difficult time imagining a conventional receiver design (even one implemented in DSP) that would infringe on this patent. In at least one of their papers they even contrasted their receiver architecture to a conventional BPSK receiver. All that being said, I suspect that there is no real market for a WWVB based timing product. Even before the modulation change there were no commercial WWVB based timing products, and there hadn't been in several years. So, If you want to buck the trend and make such a product, You can probably do so without much fear of someone coming after you. I suspect though that 5 years hence you will be able to hold your equipment users group meetings in a room the size of a broom closet. And that’s assuming you are still using yours! Dale -Original Message- From: Bob Camp Sent: Sunday, August 10, 2014 8:41 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] WWVB for Time Nuts Hi Keep in mind that it’s relatively cheap (big company wise) to get a patent. It’s only got major value once the courts uphold it as valid. That process costs real money. I’ve seen a variety of estimates on how many patents get issued that would never stand up to challenge. None of the estimates I’ve seen have been below 50%, some are a lot higher. Since the patents for sunscreen that’s only useful on the moon also get tossed into some of the estimates, who knows what the real numbers are. Often the protection process becomes a “we have 689 patents on this gizmo” sort of thing. Even if 99% of them are bunk, it will cost you a lot to prove that. You still would have to pay based on the 1% that turn out to be valid. The net result is a system that never challenges (and clears out) the junk. Bob On Aug 10, 2014, at 4:24 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: On 10 Aug 2014 05:39, Jim Lux jim...@earthlink.net wrote: (but, I gotta say that a lot of the patents that get published in the back of things like IEEE Ant and Prop Magazine seem, to me, to be pretty obvious..) I have not looked at patents recently, but most I have looked in the past are fairly obvious to someone skilled in that area. Another large group appears to be useless things. Perhaps time-nuts should stick on a web site a list of 100 obvious things that they believe someone might just try to patent. Once an idea is disclosed like that, it should stop a patent being issued. Perhaps a braille clock with an internal atomic frequency reference. I don't suppose anyone has made one, as the demand would be low, but it is in my a opinion fairly obvious approach for a skilled person. I assume there is some time delay (probably in the range 100 us to 10s) between one observing a clock and one's brain decoding it. So for a person to believe that they know the time, the clock actually has to display it a bit fast. But more seriously, one could probably have some impact on time nut related patents by documenting semi obvious things on a web site in advance. I recall being at the patent office in London and see someone had a patent on a screen built into a microwave oven hooked upto a video
Re: [time-nuts] WWVB for Time Nuts
Actually, why was the WWVB modulation format changed, before a functioning new transmission system was at least demonstrated? Since the new --supposed to be superior --system exist on paper, if at all only, but not available to replace a more or less usable usable one. 73 Alex On 8/10/2014 8:14 AM, Dale J. Robertson wrote: Hi, How does patent infringement litigation get started anyway? I would think that the infringement claim would have to be specific i.e. you are infringing on our patent number blah, claims blah, blah, blah blah. not just you are infringing on our patent. you need to halt production immediately and can't resume until you have properly guessed how you are infringing and stop, or, pay us a crapload of money. AFAICT, the patent includes no claims regarding conventional BPSK detection and demodulation. The patent seems to be about arranging the bits in a 'more efficient' way that, when taken advantage of by the receiver described in the patent, makes possible a 20dB process gain over a conventional AM envelope receiver. I am having a difficult time imagining a conventional receiver design (even one implemented in DSP) that would infringe on this patent. In at least one of their papers they even contrasted their receiver architecture to a conventional BPSK receiver. All that being said, I suspect that there is no real market for a WWVB based timing product. Even before the modulation change there were no commercial WWVB based timing products, and there hadn't been in several years. So, If you want to buck the trend and make such a product, You can probably do so without much fear of someone coming after you. I suspect though that 5 years hence you will be able to hold your equipment users group meetings in a room the size of a broom closet. And that’s assuming you are still using yours! Dale -Original Message- From: Bob Camp Sent: Sunday, August 10, 2014 8:41 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] WWVB for Time Nuts Hi Keep in mind that it’s relatively cheap (big company wise) to get a patent. It’s only got major value once the courts uphold it as valid. That process costs real money. I’ve seen a variety of estimates on how many patents get issued that would never stand up to challenge. None of the estimates I’ve seen have been below 50%, some are a lot higher. Since the patents for sunscreen that’s only useful on the moon also get tossed into some of the estimates, who knows what the real numbers are. Often the protection process becomes a “we have 689 patents on this gizmo” sort of thing. Even if 99% of them are bunk, it will cost you a lot to prove that. You still would have to pay based on the 1% that turn out to be valid. The net result is a system that never challenges (and clears out) the junk. Bob On Aug 10, 2014, at 4:24 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: On 10 Aug 2014 05:39, Jim Lux jim...@earthlink.net wrote: (but, I gotta say that a lot of the patents that get published in the back of things like IEEE Ant and Prop Magazine seem, to me, to be pretty obvious..) I have not looked at patents recently, but most I have looked in the past are fairly obvious to someone skilled in that area. Another large group appears to be useless things. Perhaps time-nuts should stick on a web site a list of 100 obvious things that they believe someone might just try to patent. Once an idea is disclosed like that, it should stop a patent being issued. Perhaps a braille clock with an internal atomic frequency reference. I don't suppose anyone has made one, as the demand would be low, but it is in my a opinion fairly obvious approach for a skilled person. I assume there is some time delay (probably in the range 100 us to 10s) between one observing a clock and one's brain decoding it. So for a person to believe that they know the time, the clock actually has to display it a bit fast. But more seriously, one could probably have some impact on time nut related patents by documenting semi obvious things on a web site in advance. I recall being at the patent office in London and see someone had a patent on a screen built into a microwave oven hooked upto a video camera so you could check on the security of your premises while cooking. I guess with China pretty much ignoring patents, it might become more attractive to keep something a trade secret rather than patent it. I believe Samsung and Apple have recently agreed to drop patent infringement cases against each other outside the USA http://www.forbes.com/sites/amitchowdhry/2014/08/06/apple-and-samsung-drop-patent-disputes-against-each-other-outside-of-the-u-s/ I know BT and Marconi did a similar thing, as I guess that they realised that they were spending an excessive amount of money fighting each other over patent infringement. Dave.
Re: [time-nuts] Lamp for FRK Rubidium Needed
How did you make the measurement that showed a 0.8 Hz difference? What are the specs on your Racal reference? When was it calibrated and against what standard? That will tell you how much confidence to put in it's frequency. As others have said, an FRK isn't a primary standard and should be calibrated against a primary standard. However, 0.8 Hz is an error of 8e-8. I don't believe it's possible for a Rb standard to lock and be that far off. From your web site you seem to have quite an assortment of HF radios. Do any of them have enough resolution to do a quick check by using one of them as a transfer standard? Measure a known-accurate radio station frequency and then measure both the Racal and the FRK. Ed On 8/10/2014 4:01 AM, Peter wrote: Thanks to the help from members here I now have a locking FRK. My bulb looked pretty clear, and i couldnt find any deposits or bits inside, but decided to give it a good soaking at about 150 deg C using my hot air re-work gun for about 10 mins. I have checked it against my Racal ovened reference and found a discrepancy of about 0.8 Hz. Now the million dollar question...Can I be sure the FRK is good before I start to use it as my standard frequency? Is the FRK constructed in such a way that the frequency accuracy is assured, or do I need some way of verifying the FRK, or calibrating it. I dont want to trim my ovened reference to the rubidium, only to find the rubidium is not as accurate as I thought? Sorry if dumb questions, but just starting my quest for time nut status!!! Thanks Peter G0RSQ ___ 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] Datum ts2100 gps error code 41: New clone ace III
Jason Thank you for your information on the Datum 2100 GPS - I now have this basically 'set-up' and I wonder, as its a Trimble Rx. if it can be accessed through its RS232 port using the Trimble software ? Roy Phillips. -Original Message- From: Jason Rabel Sent: Friday, July 25, 2014 10:45 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Datum ts2100 gps error code 41: New clone ace III Are you sure your GPS module has the correct settings of 9600 8-O-1 TSIP IN TSIP OUT? ___ 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] VLF Phase-tracking receivers.
On 10 Aug 2014 at 6:24, paul swed wrote: Hello again, Paul. Thanks for replying. Please see below. On iPhone Yes but those stations are fsk so the offsets an issue. As I understand it from back in the 1970s when I was first working on this sort of thing, the modulation is not FSK, but MSK (whatever that is) at something like 25 to 50 Hz, and the Navy installed the necessary equipment in the 1970 time-frame to assure that the transmitted signals are phase-stable. The same thing, apparently holds true for GBR and some of the other stations like those. Russian, for instance. I have no idea what, exactly, has occurred in this area since then though. We may assume the transmitter is accurate. Yes. But how accurate? That is a good question. I have no idea at this point. I'll try to find out. Then the fsk generator Well, as I said above, it is not FSKexactly... I DO know that the Navy had problems when they first tried FSK with their antenna tuning methods. Due to the extremely hi Q of their antenna systems, any useable frequency shift (at the receiver) was so great that it pretty much threw their antennas out of tune on either mark or space. Thus, they had to use a different method. I never did learn what that method was. Perhaps now is the time for me to find out. Thanks again, Ken W7EKB ___ 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] Lamp for FRK Rubidium Needed
Having had more than ten FRK's and M100's on my bench and once locked none where as low as any thing in E-9. What you should buy is a ubox for $ 16 shipping included and you will with your counter be able to get better than 1 E-9 for testing. Bert Kehren In a message dated 8/10/2014 2:30:50 P.M. Eastern Daylight Time, ed_pal...@sasktel.net writes: How did you make the measurement that showed a 0.8 Hz difference? What are the specs on your Racal reference? When was it calibrated and against what standard? That will tell you how much confidence to put in it's frequency. As others have said, an FRK isn't a primary standard and should be calibrated against a primary standard. However, 0.8 Hz is an error of 8e-8. I don't believe it's possible for a Rb standard to lock and be that far off. From your web site you seem to have quite an assortment of HF radios. Do any of them have enough resolution to do a quick check by using one of them as a transfer standard? Measure a known-accurate radio station frequency and then measure both the Racal and the FRK. Ed On 8/10/2014 4:01 AM, Peter wrote: Thanks to the help from members here I now have a locking FRK. My bulb looked pretty clear, and i couldnt find any deposits or bits inside, but decided to give it a good soaking at about 150 deg C using my hot air re-work gun for about 10 mins. I have checked it against my Racal ovened reference and found a discrepancy of about 0.8 Hz. Now the million dollar question...Can I be sure the FRK is good before I start to use it as my standard frequency? Is the FRK constructed in such a way that the frequency accuracy is assured, or do I need some way of verifying the FRK, or calibrating it. I dont want to trim my ovened reference to the rubidium, only to find the rubidium is not as accurate as I thought? Sorry if dumb questions, but just starting my quest for time nut status!!! Thanks Peter G0RSQ ___ 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] VLF Phase-tracking receivers.
Unless on what you were working on it had a different meaning, MSK means Minimal Shift Keying. It is still a PSK modulation of any order, however the transition between significant phase locations is not instantaneous, but, shaped in various ways to smooth the transition. This results in a waveform that has a minimal AM component which then consequently reduces spectral regrowth when amplified by a non-linear amplifier. Allows for closer channel spacing, and is generally nicer, at the expense of additional complexity. 73 - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Kenneth G. Gordon Sent: Sunday, August 10, 2014 12:27 PM To: paul swed; time-nuts@febo.com Subject: Re: [time-nuts] VLF Phase-tracking receivers. On 10 Aug 2014 at 6:24, paul swed wrote: Hello again, Paul. Thanks for replying. Please see below. On iPhone Yes but those stations are fsk so the offsets an issue. As I understand it from back in the 1970s when I was first working on this sort of thing, the modulation is not FSK, but MSK (whatever that is) at something like 25 to 50 Hz, and the Navy installed the necessary equipment in the 1970 time-frame to assure that the transmitted signals are phase-stable. The same thing, apparently holds true for GBR and some of the other stations like those. Russian, for instance. I have no idea what, exactly, has occurred in this area since then though. We may assume the transmitter is accurate. Yes. But how accurate? That is a good question. I have no idea at this point. I'll try to find out. Then the fsk generator Well, as I said above, it is not FSKexactly... I DO know that the Navy had problems when they first tried FSK with their antenna tuning methods. Due to the extremely hi Q of their antenna systems, any useable frequency shift (at the receiver) was so great that it pretty much threw their antennas out of tune on either mark or space. Thus, they had to use a different method. I never did learn what that method was. Perhaps now is the time for me to find out. Thanks again, Ken W7EKB ___ 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] VLF Phase-tracking receivers.
As I recall (it was a long time ago), it was called Minimum Shift Keying and used the minimum frequency shift (FSK) that would permit reliable detection of a bit (mark or space) at the given information rate. Something like 25 Hz shift at 50 baud keying. But it was necessary to control the instantaneous phase of the signal very carefully. As a result the spectrum of an MSK signal is quite distinct from that of an ordinary FSK signal. As I recall. 73, ... MartinVE3OAT Ken W7EKB wrote : As I understand it from back in the 1970s when I was first working on this sort of thing, the modulation is not FSK, but MSK (whatever that is) at something like 25 to 50 Hz, ... (snip) ___ 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] WWVB for Time Nuts
On 8/10/14, 8:30 AM, Bob Camp wrote: Hi …. which also eliminates a full examination and challenge. Bottom line as I still see it - For Time Nuts one off / home use / zero profit/ personal experimentation, I would not worry about the patents that are or are not present on the receiver for the WWVB format. Indeed.. the damages, such as they are, are going to be small. Unlike copyright, there aren't any statutory damages. So what are they going to sue for, other than a prohibition against you doing it in the future. They can sue for royalties you should have paid.. gonna be small for one unit. They can sue for profits they would have made had you not infringed..speculative damages are VERY hard to prove. I would not go out and start selling a product without some sort of protection. That's for darn sure.. that's where damages can get bigger, and you also have your investment. (This is why patent pending on a widget is a useful warning. It keeps you from investing in something you won't be able to sell if the patent issues.) In that case if they want 10% of my (likely zero) profits, that’s not going to stop me. The same would be true if they are after 1% of my gross (one percent of $10 programmed uP’s times 100 pieces isn’t much). The killer would be some sort of flat license fee dimensioned in kilobucks. Unfortunately, the license agreements I've seen tend to be flat fee plus percentage where you get credit for the flat fee. For instance, maybe you have a 1% gross sales royalty and an initial 50k fee. When you've sold your first $5M, you start paying the 1%. The flat fee is designed to a) pay for the time and labor involved in negotiating the license agreement. Unless it's truly cookbook, you're looking at 10-20 hours of a lawyer's time at several hundred/hr. b) encourage the licensee to actually use the invention, particularly in the case of an exclusive license. That way, the licensee has some skin in the game, and it prevents licensing to keep a competitor out of the market In any sort of gross sales deal, there's going to be some negotiating about what transaction the gross applies to. A tiny chip in a million dollar piece of equipment with the 1% applying to the $1M is going to raise eyebrows. As a comparison.. the license fee, last I checked (10 years ago), for FireWire/IEEE 1394 was $0.50/port. Not a big deal for a spacecraft with maybe a dozen ports. A huge deal if you're cranking out millions of game consoles or PCs a month. video codecs are another royalty example..MPEG LA charges no royalty for the first 100,000 units of a licensed product; sublicensees pay 20 cents per unit up to 5 million and 10 cents per unit above 5 million. The current agreement includes an annual limit: “The maximum annual royalty (‘cap’) for an Enterprise [is] $6.5 million per year in 2011-2015.” (at least that's what I found online.. these things tend to be negotiated.. there's not a price list handy) Until they come up with details there’s no real way to know how much of an issue this would be, even for a hobby project. It might be worth looking at the DVSI AMBE audio encoding patents (as used in, say, D-star) and their history. There's a lot of interest in developing software implementations, but DVSI seems to have been pretty efficient at keeping any implementations out of circulation. (I just found that the technology was actually developed at MIT..and they've actually lost one of the lawsuits for infringement) They've pretty much said buy a chip with our licensed property.. They have 5 years of protection on this, and the clock has been running for at least a year, maybe more. At the rate this is going, there might not even be a chip before the 5 years runs out. ___ 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] VLF Phase-tracking receivers.
On 8/10/14, 9:26 AM, Kenneth G. Gordon wrote: On 10 Aug 2014 at 6:24, paul swed wrote: Hello again, Paul. Thanks for replying. Please see below. On iPhone Yes but those stations are fsk so the offsets an issue. As I understand it from back in the 1970s when I was first working on this sort of thing, the modulation is not FSK, but MSK (whatever that is) at something like 25 to 50 Hz, and the Navy installed the necessary equipment in the 1970 time-frame to assure that the transmitted signals are phase-stable. The same thing, apparently holds true for GBR and some of the other stations like those. Russian, for instance. MSK = Minimum Shift Keying... Run the bits through an appropriate filter (usually a Gaussian) before feeding them into the modulator. The minimum comes from the fact that the frequency deviation (or phase shift) is the smallest you can have and still decode the bits, so it has very high spectral efficiency (e.g. maximum bps/Hz). The well known G3RUH 9600 bps packet modem is close to being a GMSK modem: deviation is 3kHz for 9600 symbols/sec and uses an 8 tap FIR filter in the modulator. Bluetooth uses GMFSK I have no idea what, exactly, has occurred in this area since then though. W ___ 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] VLF Phase-tracking receivers.
On 8/10/14, 11:54 AM, Mike Feher wrote: Unless on what you were working on it had a different meaning, MSK means Minimal Shift Keying. It is still a PSK modulation of any order, however the transition between significant phase locations is not instantaneous, but, shaped in various ways to smooth the transition. This results in a waveform that has a minimal AM component which then consequently reduces spectral regrowth when amplified by a non-linear amplifier. Allows for closer channel spacing, and is generally nicer, at the expense of additional complexity. 73 - Mike I can also be FSK.. but it's essentially the narrowest band simple modulation that is constant envelope. ___ 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] VLF Phase-tracking receivers.
On 10 Aug 2014 at 15:24, Martin VE3OAT wrote: As I recall (it was a long time ago), it was called Minimum Shift Keying You're correct: I just looked it up. and used the minimum frequency shift (FSK) that would permit reliable detection of a bit (mark or space) at the given information rate. Something like 25 Hz shift at 50 baud keying. But it was necessary to control the instantaneous phase of the signal very carefully. Yes again. Back in the 1970s, I was working with a fellow who was doing VLF propagation research. We were notified that the U.S. Navy had shifted to MSK and some method of stable phase transmission. The Navy told us they were installing special equipment to make that happen. As I remember it, they called it something like coherent phase transmission, but I could be wrong. There is a note in the manual I found for the 599-CS to that effect, in MY handwriting and signed with my initials. As a result the spectrum of an MSK signal is quite distinct from that of an ordinary FSK signal. As I recall. Well, you have an excellent memory. :-) Ken W7EKB ___ 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] Worlds first time code generator and ultimate decoder
This is just for fun guys; so don't take it over seriously however that said; this is indeed the first recorded use of timing for synchronization so far as I can find.and it ties in with my other hobby; vintage/ antique phonographs. I think you will enjoy it as much as I did.so read on: Most everyone knows about Edison in 1877 patenting the recording of audio but fully 17 years prior to that Scott in Paris France patented the Phonautogram which was finally proven in 2008 to be the oldest recorded sound ever when it was finally decoded. It was done by speaking into the Phonautogram device Scott Koenig built to put voice squiggles of audio lines onto paper coated with lampblack which he did as far back as 1853 but those can't be decoded for multiple reasons; like the fact Scott wasn't really interested in playing them back so some of the recordings actually backtracked on paper in time which violates the rules a bit so only the later ones can be reverse-engineered. So what made the one of 1860 work? This is the good part! It took the researchers quite some time to figure out that in parallel with the voice squiggle was a perfect sine wave that was ultimately determined to be a musical tuning fork on then standard A of 435 Hz. Yes we all know 440 became the standard later but at that time an A was at 435 before you hit REPLY and toss things at me.. Anyway; Scott vibrated a fork squiggle along with the voice pattern and the first time code for synchronization was created in 1860 which can be seen here: http://nesssoftware.com/home/asn/homepage/teaching/exp-lectureNotes/110127-p honautograph/phonautograph_rev.html note you have to scroll about halfway down the page to get to the image of the voice paper but it is sure worth it now that you know what to look for. Note that you can actually HEAR the end results of this squiggle-on-paper which Scott was only able to encode but never decode and I got to hear it at the Antique Phonograph Society back then..relived today and well documented in this large PDF that is really cool to view: http://www.firstsounds.org/publications/facsimiles/FirstSounds_Facsimile_05. pdf For those that really want to hear MP3 renditions of this miracle go here: http://firstsounds.org/sounds/scott.php and step back 154 years in time to the first recorded and frequency/ time-synchronized recordings made..enjoy as it is intended or just hit Delete if you think there are faults in this! Robert L. (Bob) Burchett Certified Communications Engineer Enterprise Electronics Contractors License 522372 22826 Mariposa Ave. Torrance CA 90502 310.534.4456 bob.burch...@eeontheweb.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] VLF Phase-tracking receivers.
On 10 Aug 2014 at 19:00, Jim Lux wrote: It can also be FSK.. but it's essentially the narrowest band simple modulation that is constant envelope. As I said, back in the 1970s, the Navy installed special equipment to enable phase-stable output. Dunno the exact details, but that was what I was told back then...by the Navy. Still dunno if my Tacor 599s will even listen to VLF stations now, but I intend to try them. VLF has always interested me... I have several operable VLF receivers: RAK, RBL, SRR-11, AN/URM-6, NM-40A, R-389, etc. RAK is interesting in that although a TRF, it still exhibits single-signal CW reception: the other side of zero-beat simply doesn't exist. I was amazed... Ken W7EKB ___ 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.
