Re: [time-nuts] eLoran test 6 Feb for almost 2 months
All Loran C signals are transmitted at precisely 100.0... KHz. They are a pulse signal system, where each member of the chain uses a different repetition rate to time the placement of its pulses. The repetition rates are designed so that they pulses from any two chains are not coincident, but for random times, over very long intervals. There are numerous Wiki's, and other sources of information that can be found by searching for Loran C. -Chuck Harris John Marvin wrote: > I don't have a Loran receiver, and I live in Colorado. But I'd still like to > check > late at night to see if I can see a signal on my SDR receiver. I tried > looking at old > posts, and did some research online, but the best I can tell is that Loran C > (and I > assume eLoran) is transmitted at around 100 Khz. Anyone know precisely what > frequency(s) are used by the Wildwood eLOran station? > > Regards, > > 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] Li-ion Battreries
One of my hats is working with a recycler to help them best utilize their input stream of recycled electronics. To that end, I take a lot of things apart, looking for failure mechanisms. This allows me to discover common problems, and to suggest which items are economical to repair, and which aren't. In the course of that activity, I have observed a lot of failed lithium battery packs. The most common failure is due to the pack being allowed to discharge too deeply. The protection electronics is happy to disconnect individual cells when they have reached a safe lowest voltage, which is good, but it doesn't do a very good job of protecting cells that are then left for weeks, months, or years in that discharged state. Eventually the cells self discharge (fueled by the protection circuitry's monitoring circuits) to a point where the protection circuitry won't allow them to be charged anymore. If you catch the packs quickly enough, you can bypass the protection circuitry, and pump some charge directly into the cells to restore function. If you wait too long before restoring the cell, they will often get hot, swell up, catch fire, and sometimes explode. They will also do this if you physically abuse the cells by denting them, heating them too hot, or bending them too far. You have been warned! Once you have a cell that functions properly, but maybe at a reduced capacity, it will continue to work reliably, and will continue to slowly lose capacity, just as a new cell would. -Chuck Harris Adrian Godwin wrote: > Recovered cells aren't only sold through ebay parts adverts - they're also > used for production. I recently bought a few cell phone boosters which > consist of an 18650, a charge circuit and a voltage booster to 5V. > > They were low cost and nicely made with an extruded aluminium case and they > worked very well in my application. But on taking one apart, it was > apparent that they'd used a recovered cell. > > I've no complaints given the price, but be aware that the cell phone packs > may not be new either. > > > On Sun, Jan 22, 2017 at 4:48 PM, Didier Juges <shali...@gmail.com> wrote: > >> Well worth mentioning that you have found a reputable vendor. I may give >> them a try. >> >> A while back, I bought a dozen 18650 inexpensive(<$5 each) cells from 3 >> vendors picked at semi-random on eBay (4 from each) for evaluation and I >> tested each one of them with a data logger. >> The best one had about half the advertised capacity, the others went down >> from there. Important to observe that none of the set I bought were even >> remotely matched, a crucial consideration if you are going to put them in >> series (a balancer will only ensure your pack is no better than the worst >> cell in the pack). >> Many of the 18650 cells you find on eBay (and maybe other places) are >> actually coming from old laptop battery packs that normally should have >> been discarded/recycled. >> >> In my anticipated application, I only needed one cell (to be followed by a >> small boost converter), so the issue of balance and matched set was not >> important, but simply I needed the capacity and none were remotely >> satisfactory. I ended up using cell phone booster packs, since I needed 5V >> anyway. >> >> >> On Sun, Jan 22, 2017 at 9:44 AM, Bert Kehren via time-nuts < >> time-nuts@febo.com> wrote: >> >>> I use 4 cell balancing and protection circuits, cost a couple of $ more >> but >>> well worth it, I use holders because of limited availability of cells >>> with straps, but rest assured they are held down (discarded PCB)'s, >>> I on purpose did not get into technical details I was only trying to >> share >>> reliable sources, based on disappointing past experiences. >>> Bert Kehren >>> >>> >>> In a message dated 1/22/2017 10:00:45 A.M. Eastern Standard Time, >>> att...@kinali.ch writes: >>> >>> Hoi Bert, >>> >>> On Sat, 21 Jan 2017 08:08:22 -0500 >>> Bert Kehren via time-nuts <time-nuts@febo.com> wrote: >>> >>>> purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain Rechargeable >>> Battery >>>> INR18650-35E_ >>>> >>> (http://www.ebay.com/itm/112173495496?_trksid=p2060353. >>> m2749.l2649=STRK:MEBIDX:IT) for two reason 10 A load and >>> good price. These >>>> cells have no protection, which I want, since I will for our >>> applications >>>> stack 4 with a 4 cell controller and in two application also parallel >>> cells >>>> for a total of 8. I have now completed my tests and concentrate my >>
Re: [time-nuts] Li-ion Battreries
Just a quiet message that needs to be said: 18650 style LiIon cells are indeed one of the most common styles of LiIon cells, but with their popularity comes a great deal of fraudulent sales activity. The 18650 cells are used in all sorts of trendy gadgets, like the vape appliences for niccotine addicts, over powered green laser pointers, and vibrators for... well... urhmm...ahhh, I can't say. I went on a quest to try to buy 18650 cells for cheap prices, and then tested them on my Christie CASP battery charger/tester, and I found that I could buy the things wrapped with the labels of Samsung, Sanyo, UltraFire, PowerSonic, and probably a dozen other brands, labeled with 3000 through 9800mAH capacities. In testing, I found two things. If the batteries came from eBay, or Amazon, they would weigh between 1/3 and 1/2 as much as the manufacturer's spec sheets said they would, and they would test at between 400 and 500mAH. And that was with allowing them to discharge until their internal protection circuitry shut them down... in other words to an unsafe level. So, the moral of my story is know your sources, and do test every one... a twist on the old saying: Don't trust but verify. I quit the project, as I feared that the high number of items I was declaring as counterfeit for refund, would soon catch up with me and render me unfit for ebay and Amazon purchases. The safest, surest supply I have found is discarded laptop batteries for Dell computers. Bust them apart, and you will find that all but one of the cells is in good condition. The one bad cell can almost always be resurrected by charging it manually to 4.2V at less than 1C current. Note, they won't have the protection circuitry installed as part of the cell, but you can buy that part on eBay with pretty good results.. -Chuck Harris Attila Kinali wrote: > Hoi Bert, > Some small remarks: 18650 is by far the most common form factor > of Li-Ion batteries on the market. This is IMHO the better choice > than the 26650 if you want to be able to replace them in 10-20 years. > > If you stack Li-* batteries, you will need to have a controller that > monitors each cell individually while charging or has some other means > of ensuring that none of the cells are overcharged (or rather that they > are charged the same amount). This kind of circuit is called balancer. > A protection circuit does _not_ replace a balancer. The protection circuit > is only to protect against catastrophic failure. Ie it is still possible > to overcharge a battery even if it has a protection circuit. You also do > not know what the protection circuit does to protect the cell. There are > a lot of chips out there, that simply open a switch and thus disconnect > the cell. In this case, the protection circuit of one cell will disconnect > the whole stack and break charging. > > A lot of the multi-cell Li-Ion charger chips have integrated cell protection > circuitry. Ie if you use one of them, you will not need an additional > protection circuit. But be aware, the regulation for battery protection > circuit states that the circuit has to be wired fix onto the battery > in a way that this connection cannot be broken (without breaking the > housing of the battery pack). The reason for this is, i think, pretty > obvious. I would recommend that you solder each cell indidividually > into your circuit instead of using some kind of holder. Or if you are > using a holder, make it such that there is no chance any of the cells > can be accidentally short circuited. > > Attila Kinali > ___ 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] wifi with time sync
If there is a modern microwave oven with a switching power supply, or a cordless telephone around, you might want to look there. The old linear supply ovens were easy to deal with because they presented a strong CW signal that drifted around as voltage, load, and temperature changed. The switcher ovens simply splatter the whole ISM band with strong microwave noise. -Chuck Harris Bob Camp wrote: > Hi > > It just so happens that I’m trying to track down an issue with my WiFi as > I type this. My *guess* is that there is a dropout going on. The only easy > way I can see to get a round trip time with a high data rate is to run ping. > It’s the only tool that gives me something that is fast enough to spot issues. > Is it perfect? certainly not. Is it an upper bound that is also likely the > limit > for things like NTP - in my experience it sure is. That of course assumes > the gizmo that sends the pings back does so quickly and consistently. I’ve > spent enough time testing that side of it that I’m quite sure it’s true in > this case. > > Bob ___ 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] Line Voltage - USA
Leap seconds only matter if you are counting seconds. The power line isn't. As long as they keep the frequency near nominal, they are fine. -Chuck Harris J wrote: > Power utilities tweak the system frequency on a daily basis to keep MAINS > powered clocks correct. I wonder what their correction strategy was for the > leap second? > > On Tue, Jan 3, 2017 at 11:05 AM, Vlad <t...@patoka.org> wrote: ___ 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] Line Voltage - USA
It's not a split phase system in US residential power, it is a center tapped 240V single phase system. Split phase systems have historically had a 45-90 degree phase difference between the split phases. The US system, depending on which wire lead you take as your reference, has a 0, or a 180 degree, phase difference. The reason it is done this way, is for safety. The center-tap of the mains transformer is grounded to earth, as is the neutral, and service entrance panel grounds. This way, if the power company installed grounding system is working properly, the highest voltage that any residential customer could accidentally encounter would be 120V to ground. (It is not an accident to go mucking around inside of a 240V range/dryer socket, or the service panel!) As it has been noted, if a US based system is defective, people can get hurt. The same is true for the European system. Back in the dark ages of ~220V electrical distribution systems in Europe, the reaping due to unintentional grounding of a ~220V wire was so common and extreme, whole house ground fault interrupters were mandated for all residential/small business power systems therein. And, in so far as properly functioning GFI protectors are in use, and can be maintained, they have been wildly successful! I will have to leave discussions of which system is better/safer/ cheaper/more reliable, for another time and forum...preferably one where there is beer and loud music. -Chuck Harris Gregory Maxwell wrote: > On Mon, Jan 2, 2017 at 4:49 AM, Bill Byrom <t...@radio.sent.com> wrote: >> Most US homes and small businesses are powered by what is commonly called a >> "split-phase" 240 V feed. The final distribution system transformer has a >> 240 V >> center-tapped secondary. The center tap is grounded, and three wires are fed >> to >> the building (actually it might be up to around 6 houses): (1) Leg L1 or >> phase A >> (red wire) -- This wire will measure 120 V to the neutral or 240 V to Leg >> L2. >> (2) Neutral (white wire) -- This wire is grounded at the distribution system >> and >> at the service entrance to the building. (3) Leg L2 phase B (black wire) -- >> This >> wire will measure 120 V to the neutral or 240 V to Leg L1. > > When someone here previously mentioned observing high voltage, one possible > cause > for this in this common "split-phase" configuration is that if the neutral > wire > is overloaded, damaged, poorly connected, or otherwise has high resistance, > the > voltage on the two legs will swing wildly and in opposite directions > depending on > load. > > So, e.g. if you put a 1kw load on L1 while L2 is nearly unloaded then perhaps > L1s > voltage drops to 108v while L2 rises to 132v. > > The reason for this is that, e.g. imagine that the neutral were removed > completely > you would effectively be connecting your appliances in a parallel-series > circuit > (all on L1 in parallel, all on L2 in parallel, the both in series) across the > 240v > feed. > > I've had issues with neutrals several times in the past, and in one instance, > temporarily dealt with it by moving as much of the load to 240v as I could, > manually balancing the remaining loads, and then using a digital multi-meter > to > dynamically control some additional load to keep the voltage sane on each > side. > > I think the fact that you can end up with a much higher voltages at the > outlet if > the neutral has problems is one of the more unfortunate properties of the > split-phase approach. ___ > 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] [Summary] HP 115CR Clock Powerup / Documentation
I think the click was probably made loud intentionally. It would make it easier to set the clock accurately to within a fraction of a second. It would also make it quite evident if two clocks were out of sync. -Chuck Harris paul swed wrote: > Wow Mark thats not what I would have expected from the Patek. But then I > never had one. Remember "You never own a Patek it just goes from generation > to generation". At least thats what the ad says. So imagine someone in your > family will be wearing the 5065 on there wrist one day. > Regards > Paul. > > On Sat, Dec 24, 2016 at 12:05 PM, Mark Sims <hol...@hotmail.com> wrote: > >> No problem, stick a tiny CPU + audio amp in the corner of the box that >> generates an anti-phase noise canceling signal, >> >> That said, I never start the Patek-Philippe clock in my HP 5065A rubidium >> since it ticks loud enough to be heard on the next planet. >> >> >> >>> If I do ever see one at the hamfest after reading this thread I am pretty >> sure I will stay clear of it. Who needs the noise. >> ___ > ___ 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] HP 115CR Clock Powerup / Documentation
They are fun little (ha, ha) clocks. There really is no need to ramp up power. Go for broke, and turn it on. The only issue you will find in these is a host of wet tantalum caps that may, or may not be bad. They are on terminal strips, and are the caps in silver plated metal cans with teflon seals on the large end. The failure is sulfuric acid leaking out of the lead on the teflon end. The other failure issue is the ball bearings on the motor. The grease is all but certain to be hardened by now. You might be able to work some light motor oil between the shaft bushing and the seal. The motor will *not* start by itself. You have to open the clock, press a couple of buttons to start the dividers, and give the knurled knob on the motor's shaft a spin. Be careful when setting the odometer display, as it is quite possible to lock it up. I don't remember how that happens anymore, but it can. These clocks are not a lot of fun to live with. They sing along quite loudly at 1KHz. -Chuck Harris Hugh Blemings wrote: > Hi, > > I've been fortunate enough to acquire a HP 115CR Frequency Divider/Digital > Clock - > it's electromechanical and I suspect built in the mid/late 60s - just > slightly older > than your humble correspondent. > > It's similar though not identical to the 115CR shown here > http://www.leapsecond.com/hpclocks/ > > I'd like to fire it up - given it's age my thought was to use a current > limited 24V > bench supply and slowly ramp up the voltage the first time - would welcome any > thoughts on this. I gather from the supporting documentation for the > powersupply > it's rated at drawing ~250mA > > I've been unable to locate a scan of the owners manual or service manual > online. > Have looked at time-nuts archives, leapsecond.com and hparchive to no avail. > There > does appear to be a hardcopy available for purchase - happy to fall back to > this if > necessary, but any pointers welcome. > > My goal ultimately is to have it on display running, synchronised to a GPS > disciplied > 10MHz source :) > > Any thoughts and feedback welcome - this is my first foray into old clocks :) > > Kind Regards, > Hugh > VK3YYZ/AD5RV > ___ > 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] LH Z3801 and XP stalling
Not meaning to beat this dead horse any farther than I have to, but it worked fine under Windows XP, 7, and Linux. It only came to have a problem after the Windows 10 upgrade the MS forced on the machine one summer day. The cure was to shut off the power saving features. OBTW, the hub of which I spoke is part of the motherboard on the Dell computer. -Chuck Harris jimlux wrote: > On 12/16/16 6:33 AM, Chuck Harris wrote: >> A customer's 'doze 7 computer got auto updated to 'doze 10, >> and with that upgrade came a usb hub that timed out, turning >> itself off the only problem was, the keyboard and >> mouse were on that hub, leaving no way to signal the computer >> to turn the hub back on. > > That's a non-compliant hub. Part of the complexity in hub design is that it's > supposed to have the ability to "turn off (most) power to downstream devices" > and > "turn off (most) power to hub", but still trickle enough power through the > tree that > a leaf node can send the "wakeup" message back up the tree. ___ 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] LH Z3801 and XP stalling
Most older laptops have power saving hardware on the com ports and the lpt ports too! Try putting a blinky box on the port to see if the signals stay lit through the stall. -Chuck Harris paul swed wrote: > Thanks everyone. > However on the dell laptop its an actual rs232 port. They used to include > those. :-) > I am thinking of trying a usb port to see if that works. It is all working > nicely on a acer windoze vista laptop.But the machine I normally use for > this stuff is the dell laptop. > Regards > Paul > > On Fri, Dec 16, 2016 at 9:33 AM, Chuck Harris <cfhar...@erols.com> wrote: > >> A customer's 'doze 7 computer got auto updated to 'doze 10, >> and with that upgrade came a usb hub that timed out, turning >> itself off the only problem was, the keyboard and >> mouse were on that hub, leaving no way to signal the computer >> to turn the hub back on. Ultimately, the customer found that >> if he unplugged the monitor, plug and pray would restore things. >> For a while. >> >> -Chuck Harris ___ 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] LH Z3801 and XP stalling
A customer's 'doze 7 computer got auto updated to 'doze 10, and with that upgrade came a usb hub that timed out, turning itself off the only problem was, the keyboard and mouse were on that hub, leaving no way to signal the computer to turn the hub back on. Ultimately, the customer found that if he unplugged the monitor, plug and pray would restore things. For a while. -Chuck Harris jimlux wrote: > On 12/15/16 7:08 PM, Chuck Harris wrote: >> Sometimes, when one is doing a long run that goes past the >> usual power save times, the USB port will shut itself off. >> >> I believe that most motherboards have a setting in the BIOS >> that controls the ability of the BIOS to power the USB port >> down during quiet times. >> > > More likely the OS configures the USB hardware. On Win 7 (but probably also > anything > from WinXP on, if not before) there's a whole bunch of command line tools (or > you can > use Device Manager) to deal with the incredible complex power state behavior > of USB > devices, and more particularly hubs. > > > devcon is the command line tool here > http://support.microsoft.com/kb/311272 > > More info at: > http://www.fixedbyvonnie.com/2013/11/fix-usb-root-hub-power-management-issue-windows-7/ > > and at: > http://support.microsoft.com/kb/817900 > > devcon is the command line tool here > http://support.microsoft.com/kb/311272 > > ___ > 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] LH Z3801 and XP stalling
Sometimes, when one is doing a long run that goes past the usual power save times, the USB port will shut itself off. I believe that most motherboards have a setting in the BIOS that controls the ability of the BIOS to power the USB port down during quiet times. Perhaps that is what is happening? -Chuck Harris paul swed wrote: > Mark > I was going to respond with a humorous response. But can't come up with one. > Why does LH and XP stall only Santa knows. (Ok thats as good as it gets.) > No idea whats up but TBolt works absolutely fine on the XP Dell laptop with > a real serial port. Maybe I should try a usb port. Moved to another laptop > Vista and it seems to be working just fine. This unit has no built in > serial ports so I am using a serial to usb adaptor. > > Using the whole mess to actually repair another Z3801 that was a parts > unit. Not anymore. > Regards > Paul > WB8TSL ___ 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] Totally unrelated, but..
I don't think so. I first ran into a batch of LM340-5's that were excellent oscillators back in the 1970's... long before counterfeiting was even remotely possible. The symptom is the regulator puts out only 4.5 out of 5V. LM309's were, however, totally immune. Usually, I had to be really bad to make it happen, things like using clip leads between the power supply and load with the LM340-5 dangling in between. The answer is as simple as a couple of 0.1uf ceramic caps soldered right at the input and ground, and the output and ground pins. LDO (low dropout) regulators are very susceptible to oscillation. They need to have a couple of hundred uf of good quality capacitance right on the input and output leads. Where people usually get in trouble, is in not knowing that electrolytic capacitors lose most of their capacitance as the temperature starts hovering around 0C. The circuit works great on the bench, but fails when out hanging on a light pole... -Chuck Harris Joe Leikhim wrote: > Could the low noise parts actually be counterfeit, relabeled as such? > > Is the circuit the regulator feeds sensitive to a narrow band of voltage that > the > "good regulator" is outside of? > > Try replacing the regulator with a battery supply and resistor divider to > attain the > working voltage. Move the voltage around. A good potentiometer and stiff > filter > capacitors are recommended so as not to introduce "pot noise". > > Is something corrupting your test procedure? I had a circuit that misbehaved > due to > floating logic pins reacting to static electricity on the work bench. Another > time a > diode was photosensitive. > > > ___ 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] Swagelok and metric tubing question
Compression fittings work by crushing the surface of the tubing, and the surface of the compression insert together to make a gas tight seal. Stainless is very tenacious stuff, and as a result, when it is drawn through a die when sizing it as tubing, it gets axial ridges formed by galling, and damage to the dies. If you are planning on welding the tubing, the ridges won't matter, but if you are planning on using a compression fitting, the ridges must be eliminated, which is done by more expensive machining processes. You can sometimes use tubing with ridges with compression fittings if the fittings have a highly compliant insert made of plastic, rubber, or copper. Usually, though, when stainless is specified for the tubing, you are going to want an all stainless solution for the fittings too... which means ponying up for the more expensive polished stainless steel tubing. Don't even think of using compression fittings meant for copper, or plastic tubing on stainless. It won't go well if you do. -Chuck Harris cdel...@juno.com wrote: > Bob, > > That's the cheapest I have been able to find it. > > I'll probably go that route with the expensive version as it's specified > for compression. > > I know the original setup mixes copper and stainless but I have read that > is not recommended??? > > Cheers, > > Corby > > ___ > 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] Prologix USB-GPIB Controller
How do you know the product you "paid more money" for is not a counterfeit? The best you can do is to go to a source that you trust, for some reason, and exercise a right of return. For instance, I have found counterfeit capacitors in products from HP (in power supplies). They looked like Nichicon, but were a slightly wrong color, and had the name mispelled Nichicom. And surprise! They were bad... I have also found United "Chemicom" caps in one device. And I have found counterfeit FTDI USB->RS232 devices in medical instruments... I only know of them because of FTDI's momentary spate of anarchist activity where they had their windows drivers erase the ID from counterfeit parts... The equipment they were in was scrapped because the USB ports failed... A linux utility that I have showed me why (lsusb). As to the LTZ1000 type parts. These references appear in many, many places you might not expect. They are in about all laboratory precision scales, a lot of medical instruments, like thermometers, driers, and ovens, and the Chinese know it. They take pulls from these obscure sources, weld new full length leads onto the stubs on the original parts, and sell them as new. They probably are good enough for 99% of the applications where they might get used. aged even. -Chuck Harris Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > > Like Bob Camp said, it is better to pay more money and get a genuine > product. > > Dr. David Kirkby Ph.D CEng MIET ___ 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] Rare HP clock
There is a fist sized bag of silica gel sitting in an open from the top aluminum box. Most units also have a little 24V Nicad pack. -Chuck Harris paul swed wrote: > My speculation on the xtal. So the question is what is the empty box on the > right that looks like paper is stuck in it. > Not that any of this matters as I am not a bidder. > It may just add additional challenge for whoever gets it. > Regards > Paul > WB8TSL > > On Mon, Oct 3, 2016 at 11:01 AM, Magnus Danielson < > mag...@rubidium.dyndns.org> wrote: > >> Since you force-feed it 100 KC at the back, no crystal would be needed. >> >> Cheers, >> Magnus >> >> On 10/03/2016 04:57 PM, paul swed wrote: >> >>> Also notice the missing something on the far right that may have been some >>> xtal or something. >>> I went to look for a manual to see what it was. No luck though the manual >>> may be out there. >>> I would say its rare, but the price is going to most likely go up because >>> it is a bid. >>> Great winter project but not worth a lot of $ to me at least. Good luck to >>> whoever gets it. >>> Regards >>> Paul >>> WB8TSL >>> >>> On Mon, Oct 3, 2016 at 10:42 AM, Bob Camp <kb...@n1k.org> wrote: >>> >>> Hi >>>> >>>> Rare is indeed a relative term. I would certainly call it rare, but >>>> others >>>> might not. >>>> You likely would be the only person on your block who has one :) >>>> >>>> In the picture of the innards you can see a number of fine old wet slug >>>> tantalum >>>> capacitors. One even appears to have goo leaking out of it. I’d plan on >>>> having a >>>> lot of fun tracking down this or that part to get it working reliably. >>>> >>>> On Oct 3, 2016, at 10:27 AM, Jeremy Nichols <jn6...@gmail.com> wrote: >>>>> >>>>> I saw that. Is it really rare or just hype by the luster? >>>>> >>>>> Jeremy >>>>> >>>>> On Monday, October 3, 2016, Bert Kehren via time-nuts < >>>>> >>>> time-nuts@febo.com> >>>> >>>>> wrote: >>>>> >>>>> There is a rare HP clock on ebay for the collectors among us. I am to >>>>>> old. >>>>>> >>>>>> RARE HP H20 115BR FREQUENCY DIVIDER & DIGITAL CLOCK STANDARD VINTAGE >>>>>> >>>>> TEST >>>> >>>>> >>>>>> Bert Kehren >>>>>> ___ >>>>>> time-nuts mailing list -- time-nuts@febo.com <javascript:;> >>>>>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>>>>> mailman/listinfo/time-nuts >>>>>> and follow the instructions there. >>>>>> >>>>>> >>>>> >>>>> -- >>>>> Sent from Gmail Mobile >>>>> ___ >>>>> 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/m >>> ailman/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/m >> ailman/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] Rare HP clock
I have one of those, only in light gray. It works quite nicely, though it is obscenely loud! It has a divider network that takes 100KHz from a companion reference unit, and divides it down to 1KHz, that it uses to drive a stepper motor used as a synchronous motor. The motor drives the mechanical counter mechanism. Because the motor is being driven with a single phase 1KHz signal, you have to give its shaft a spin to start it. There is a little crank driven synchro generator that is used to insert a phase difference into the 100KHz reference signal that serves to shift the edge of the 1PPS output. It is built into a cast aluminum chassis, that is sealed with O-rings, and even has a humidity monitor to show the condition of the air in the unit. The biggest issues I can see with it are the strong 1KHz audio note, the condition of the ball bearings that support the motor shaft, the little herd of wet tantalum capacitors in its circuitry, and the internal nicad pack that keeps it live during short power failures.. The mechanical counter probably needs some cleaning and lubrication at this point. -Chuck Harris Dave M wrote: > It's Ebay item 351861979923 > > Dave M > > KA2WEU--- via time-nuts wrote: >> I can not find the item on EBAY , Ulrich >> >> >> In a message dated 10/3/2016 11:51:24 A.M. Eastern Daylight Time, >> jn6...@gmail.com writes: >> >> According to my -hp- catalogs it was available only in rack-mount >> form, not in a cabinet. That suggests it was being marketed to a >> specific small group so it may indeed have been manufactured in >> small quantities. >> >> Jeremy > ___ 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] notch filter for close in phase noise measurement
That is a most interesting suggestion. Suppose the filter crystal was pulled to the DUT frequency, and due to the inertia of its very high Q, was able to show you the phase noise variations of the DUT better than one might expect? -Chuck Harris Bob Camp wrote: >.One thing you may be seeing is the crystal shift frequency as it is tuned >to “accept” power from the source. > With milliwatts of power flying around, that would not be unusual. ___ 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] notch filter for close in phase noise measurement
Adrian, Simple is nice, but if we cannot talk about the limitations that come about because of the simplicity, without causing offense, how can we ever know if simple is good enough? -Chuck Harris Adrian Rus wrote: > Rick, > Why hunt goose with the cannon? The post is about a simple(r) crystal notch > filter, nothing more and nothing less. It is not about notch filters (in > general) against quadrature method, nor about number of RF components or > about their noise floor limitation. > It is about this notch filter against other notch filters. > As per simplicity, to mix 2 oscillators in quadrature one need the second > oscillator, the high level mixer, the PLL and the baseband (FFT) analyzer. > Best, > Adrian ___ 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 MFS-209 conversion information.
Thank you Charles! -Chuck Harris Charles Steinmetz wrote: > Chuck wrote: > >> The MBF distribution modules are all simple buffers, >> and are mounted on the back panel. Being distribution >> modules, they typically have 4 BNC outputs per module. > > I posted the Efratom catalog pages for the MFS series to ko4bb.com. The doc > describes and gives specifications for each piece of the MFS system. > > The file name is "Efratom MFS Series datasheet.pdf". You can search for it > at: > > <http://www.ko4bb.com/getsimple/index.php?id=manuals> > > or use the following direct link: > > <http://www.ko4bb.com/getsimple/index.php?id=download=02_GPS_Timing/Efratom/Efratom_MFS_Series_datasheet.pdf> > > > 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 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 MFS-209 conversion information.
Hi Colin, The MBF distribution modules are all simple buffers, and are mounted on the back panel. Being distribution modules, they typically have 4 BNC outputs per module. The MBF module you want to modify is the one that *drives* the MBF distribution modules. It is of the same species as the distribution modules, but has other parts of the PCB populated to allow for divide/2, and certain filters. It is mounted on the *front panel*, has no, or maybe one BNC connector. It is also labeled MBF. EFRATOM took the module reuse business a little too far in my opinion. It would have been better if they would have made a different panel label for the two species of MBF modules. -Chuck Harris Colin Bradley via time-nuts wrote: > I just received an Efratom MFS-209 GPSDO that I purchased onEbay. Everything > appears to work. The only manual that I found online is forthe MGPS > controller. > The MFS family apparently came in many different flavors allowing the > customer to > mix andmatch the components that best suited their needs. The version that I > have > has5 MBF frequency distribution modules that take 5 MHz in and distribute 5 > MHzout > to the 4 BNC connectors on the module back. These are different than > themodules > Chuck Harris described in his excellent January 2015 posting which took10 MHz > in > and distributed 5 MHz out. Does anyone have conversion informationfor > converting > this MFS-209 from 5 MHz output to 10 MHz output? A source foradditional > manuals > would also be helpful. 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] Inside of FT1200-100
Back when I was going to work on mine, I was thinking of prying the rubber away from the aluminum oven with something like a feeler gauge, but also using some naptha (lighter fluid) to help release any adhesive... I didn't get around to doing it, but that was the way I was going to progress. -Chuck Harris Ed Palmer wrote: > > > On 2016-09-26 10:00 AM, Christopher Hoover <c...@murgatroid.com> wrote: >>> > >>> >You might be able to slide something like a feeler guage down between the >>> >oven and the rubber blanket to break the oscillator free. The oven on mine >>> >is a plain metal cylinder. This way, the rubber sheet should protect the >>> >Dewar from your feeler guage. On mine, the mounting bolts for the 2N3792 >>> >transistor both have ground lugs. I think I see them on yours. You could >>> >hook something through the ground lugs and use that to pull the oscillator >>> >out of the rubber sheet and then remove the sheet later. >>> > >> Thanks Ed, >> >> I think the rubber sheet on mine is against metal. I haven't yet seen the >> glass dewar. >> >> The adhesion is huge. >> >> Do you know if the holes opposite the 2N3792 are threaded? If they are, I >> might try running the screws out and using those holes with longer screws >> as my pull points.I can't pull on the lugs hard enough -- I've tried. >> >> -christopher. >> 73 de AI6KG > > Yes, you have seen the Dewar. The silvery ring that's outside the rubber is > the top > of the Dewar. What you have to do is unstick and unfold the rubber starting > from the > open area in the center. Work your way outward. The rubber is only 2 or 3 mm > thick. Once you completely clear the rubber out of the way, you'll see the > edge of > the oven. The TO-3 transistor is mounted on top of the oven assembly. Once > you can > see the edge, you have to slide something like a long feeler gauge down along > the > edge of the oven to break it free from the rubber. Work your way all around > the > oven. It's about 85 mm long. It'll still be stuck on the bottom, but you > might be > able to pull it free. > > When I took mine apart, I ended up tearing off all the rubber at the top and > then > cutting out that ring of hard foam to get at the Dewar so I could smash it > more. I'm > guessing you'd rather not do that! :) But sacrificing the rubber on the top > might be > okay, if you have to. > > Sorry, but I don't know if the mounting holes for the transistor are threaded > or > not. In any case, since the oven and Dewar are bonded to the rubber, you're > pulling > on the Dewar when you pull on the oven. Not a good plan until you break the > oven > free from the rubber. Those Dewars are built in a rather fragile manner. > Your > typical home Thermos is much more robust. > > Ed > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ 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] Inside of FT1200-100
That is the board that contains the heater controller, and the output buffer. You need to get into the tiny vacuum thermos bottle where all of the wires go. -Chuck Harris Christopher Hoover wrote: > Top of the board stack > > https://goo.gl/photos/cUBtdTYHHWX4ZRbx8 > ___ > 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] Subject: Re: Working with SMT parts (Bob Albert)
The Chinese are certainly using a lot of solder paste, so they are a source. I tend to buy mine from Mouser, Digikey, TekSource, places like that. The last stuff I bought was made by Kester, and came from TekSource. The only problem with using the real sources is in the summer, they will pack your paste in an ice pack, and send it over night unless you insist otherwise (and absolve them of any warranty). That kind of shipping is very expensive. And, there is absolutely no possible way the paste you get from China is going to make it here and follow the manufacturer's guidelines for safe handling. So, even if you buy new and pay a premium price from China, you are getting paste that is expired by the poor handling (not refrigerated). I would bet that any paste you get on ebay is expired, for a variety of reasons. Also, I only buy tin/lead, though it is getting very hard to find. It works so much better than lead free. -Chuck Harris Bob Albert via time-nuts wrote: > Well I have found some Chinese sources of 42 - 50 grams on ebay for around > $3. Is > this the right stuff? The brand is Mechanics. > > Bob ___ 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] Subject: Re: Working with SMT parts (Bob Albert)
Uhmmm, I buy it new, and expire it myself... blush. -Chuck Harris Bob Albert via time-nuts wrote: > So where do you get this expired paste? I have tried a few searches but no > luck. > Bob ___ 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] Noisy Sulzer 2.5 - Suggestions?
Hi Ed, Nope. I just brushed off the growth, and blew the whole assembly down with compressed air. The whiskers were huge! I think they were capacitively coupling with the ground bits, and since their size and number varied in an uncontrolled way, they affected the frequency in an unstable way. These white cube shaped capacitors are something high quality. The white color is a porcelain glaze that protects the capacitor, and the wires seemed to be connected to some sort of sintered silver area on the body. -Chuck Harris Ed Palmer wrote: > That's not something I would have expected. Did you have to unsolder the > capacitors > to clean them up? > > Ed > > On 2016-08-18 10:00 AM, time-nuts-requ...@febo.com wrote: >> My old 2.5A was acting up in strange drifty ways. I opened the oven, and >> found >> that all of the white cube shaped ceramic capacitors in the oscillator were >> covered >> with fuzz on the electrode ends. I am guessing that they were growing a >> great >> tin whisker beard. I cleaned it all off, and performance improved greatly. >> >> -Chuck Harris >> ___ 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] Subject: Re: Working with SMT parts (Bob Albert)
I have had similar experience with well expired paste. I just don't worry about it. The issue is the solder is ground to such a fine powder that it has a huge surface area to oxidize. As long as you keep the air off, and refrigerate the paste, it seems to go forever. Oh, and I only use tin/lead paste, not the RoHS stuff. -Chuck Harris Steve Wiseman wrote: > On 18 August 2016 at 07:07, Bob Albert via time-nuts <time-nuts@febo.com> > wrote: >> I didn't use the liquid solder because I didn't have any and it doesn't keep >> very long. > > That's not really the case. It may change consistency so that it > behaves a little differently and fouls up automated stencilling > machines (which are the most finicky devices on the planet), but with > a human in the loop, you can expect most of a decade unless you let > it dry out or do something daft. > I'm still happily using stuff with a 2007 expiry code, in (big) > plastic syringes. Still behaves fine. (and the benefit of the > stirred-in flux and excellent wetting does make paste a joy to use > compared to even good solder wire). > 'Expired' solder paste can be a bargain. > > Steve > ___ > 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] Noisy Sulzer 2.5 - Suggestions?
My old 2.5A was acting up in strange drifty ways. I opened the oven, and found that all of the white cube shaped ceramic capacitors in the oscillator were covered with fuzz on the electrode ends. I am guessing that they were growing a great tin whisker beard. I cleaned it all off, and performance improved greatly. -Chuck Harris Ed Palmer wrote: > I picked up a Sulzer 2.5 (not 2.5A or 2.5B or 2.5C) oscillator and 5P power > supply. > It's working, but the AlDev at low tau is poor. After a few days of operation > the > AlDev @ 1sec. is only 1e-10. It's not the power supply. I'm running under > 'AC fail' > conditions with a lab power supply standing in for the batteries. This > bypasses > almost everything in the power supply. Eventually, I plan to replace the > batteries > with lead-acid and replace the circuit board with an improved circuit. > > So, I'll be opening up the oscillator to see what's what. My first 'usual > suspect' > will be the Ta capacitors, but I'm wondering about all those carbon > composition > resistors. Should I be looking at a wholesale replacement with metal film? > Maybe > just in the oscillator and AVC areas? Are there any other known trouble > spots with > these oscillators? > > I haven't been able to find any info on the 2.5. The manuals and schematics > for the > 5A and the 2.5B/C are some help, but the 2.5 is very different from the > 2.5B/C. Any > info would be greatly appreciated. > > Thanks, > > Ed > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ 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] Working with SMT parts.
I have never used the Mantis, though I considered one when my eyes started to degrade. My big problem with the mantis is all of the light that is projected on the viewing screen has to be reflected from the device being viewed. That means you are throwing a lot of heat and lumens at the device, and even with that you cannot work in a brightly lit room the projected screen will be too dim. Just about any CCD/CMOS camera meant for use as a CATV camera, when equipped with a good quality macro zoom lens, would work nicely for SMT work. A long working distance, is essential, which means good lenses. I think it would take very little expense and effort to greatly exceed the abilities of the Mantis. I, on the other hand, continue to use an Olympus Stereo Zoom microscope (model SZH), and a not so cheap Russian copy of another Olympus Stereo Zoom scope. And live with a tableau of translucent worms that cover everything I view. You get used to it... -Chuck Harris Brooke Clarke wrote: > Hi Chuck: > > The Mantis is very expensive and the arm in the EEVblog review is not as > stable as my > arm. > https://www.youtube.com/watch?v=a3o0EWHEH08 > about US$ 3300 retail, maybe $2000 eBay. > In the review he is confused about 3D vs. perspective. > The working distance does not look as long as the B > http://www.prc68.com/I/SMT.shtml#Mag > ___ 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] Working with SMT parts.
Lots of good suggestions have already been made, but for me, a boom style stereo microscope, with a distance between the objective, and the focal point of at least 3 inches works fairly well... One other thing that may force your decision, if you are older, your eyes will likely have lots of "floaters", which are debris that floats around in your eyeballs. This debris floats in and out of the center of your field of view, and looks like a bunch of translucent worms, or shadows. Your brain, the magnificent organ that it is, tries to compensate for your eye's degradation, and as long as your eyes can move about in your field of view, it effectively removes the floaters from the scenes you are viewing. However, if you use a stereo microscope, your eye position is fixed by the very limited amounts of off axis motion that will allow a through optical channel. This lack of off axis motion will emphasize your floaters in a great way, and you will see *every* *single* *one*, clearly, as if it were something you really wanted to view. Some times, the floaters will cover the exact thing you need to see clearly, and you will have to move it off axis by moving it on the microscope stage. The only answer to this problem, is to either have perfect eyes, or to use a microscope where you are looking at a screen, rather than through a pair of oculars. This way, your eyes can dart around, and inspect what they need to see clearly, and the floaters will be ignored by your brain. As far as I know, there is only one optical microscope built this way, and it is the very expensive Mantis. Because of the great expense of flat screen optical microscopes, most modern SMD viewing equipment is going to the trivially cheap method of using a CCD/CMOS color video camera and an LCD screen. You can do a lot with a cheap USB camera mounted to a boom, a fiber optic light source, or a ring light, and a laptop computer to display the image. -Chuck Harris Bob Albert via time-nuts wrote: > What are the important parameters regarding purchase of a stereo microscope? > I > see some on ebay for around $50; are those good? Bob ___ 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] Safely getting the electrical length of a connected antenna feedline
If you have *the* active antenna, it is pretty easy to make a little quadrapole circularly polarized antenna out of a couple of pieces of 141 semi-riged coax, and to transmit signal into the active GPS antenna, and measure the signal coming out of the active GPS antenna. If you don't have the actual antenna being used, you could get close by using another of the same type and manufacture. I tested all of my GPS antennas that way for gain, as a way to be sure that they were functioning properly, but there is no reason that you couldn't use a VNA to test them for phase delay, group delay, whatever you desire. You could even modulate your sweep generator with a pulse, detect the pulse with a diode, and measure the delay with your oscilloscope. -Chuck Harris Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > On 8 Aug 2016 21:23, "Bob Camp" <kb...@n1k.org> wrote: >> >> Hi >> >> An even more significant question: >> >> Is it worth doing? > >> Your antenna and module could easily have delays >> in the 40 ns range. It has no impact on a “frequency” GPSDO. It is one of > a number of static offsets in a time transfer system. >> >> Even the NIST level outfits seem to have issues coming up with a purely > mathematical answer to “what is the offset”. > > I thought i might be possible to do this with a VNA, and a test antenna > located a known distance apart. So I asked in the Keysight forum on 8th Feb > 2015 > > https://community.keysight.com/thread/23082 > > There's a replay by Dr_Joel, who is a VNA guru. Dr. Joel Dunsmore, > suggesting the use of the group delay function. In one sentence he wrote > > "What is the level of delay accuracy you are looking to achieve. With this > method, 1 nsec is reasonable, but if you need 100 psec or 10 psec, then we > will have to be much more careful." > > The thread never got a complete solution, but it might help if other look > at that, and perhaps start another thread on a similar topic, as that one > is very old. However, if you don't have a VNA, I would not bother asking, > as you are not going to get a response (no pun intended), to a non-VNA > question on a VNA forum. > > But IF it was possible to determine the delay through the antenna/filter > within a ns, it would make measurements of coax length useful, whereas as > Bob said, it is pointless unless you know the characteristics of the active > antenna. > > I don't know if there would be a way of generating a pulse and feeding that > into two antenna > > 1) Active one. > > 2) Passive one at the same distance, and same length of cable. > > The pulse should arrive at the same time if the two antennas had equal > delay. But the signal from the active one will arrive later due to the > delay. That might be possible to see on a scope. > > I think assuming that the delay in the active antenna can't be measured is > maybe an assumption that is untrue. You could perhaps do better if you > built your own antenna, and characterized the SAW filter separately. > > 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] HP5370 power supply measurements
It is important to remember that the fans specified in most of this equipment are sized so that the instrument can operate safely, in a rack full of equipment, at the maximum temperature rating for the instrument. If you plan to run at a comfortable room temperature, you can usually get by with a much smaller fan. It might be nice to leave a label somewhere that says what you did, so the next owner won't be unpleasantly surprised by it failing in his desert tent. -Chuck Harris Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > On 13 Jul 2016 08:31, "Charles Steinmetz" <csteinm...@yandex.com> wrote: > >> An external fan blowing on the heatsink keeps my 5370s nice and cool, for > about $10 each. > > So more noise. > >> *if the counters were operated 24/7/365*. I sometimes take data for a > few months straight, but very, very far from 24/7/365 on average. So for > me, break-even would be more like 50 years. > > I don't suppose Poul's main motivation is to reduce his electric bill. > >> Speaking of fan noise -- you can't really get away with replacing the > internal fan with one that moves less air, so it is hard to find a > replacement that generates significantly less noise. If you find one, > please share the make and model -- all 5370 owners would love to know. >> >> Best regards, >> >> Charles > > Surely one of the main advantages of the SMPS route is the higher > efficiently means less cooling air is required. That means less noise. > > I often here of people replacing fans with quiter ones, but I suspect that > all they really do is reduce the airflow. I believe that most of the noise > one hears is the movement of the air. From what I have read, sleve bearing > fans make a bit less noise than ball bearings fans. However, although the > MTBF of both types is similar at 20 degree C, the MTBF of sleve bearing > fans decreases quite a bit with only a modest increase in temperature. > > 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] that's really awesome
I can't imagine anyone following a link that is presented in this way. I love a lot of things, how about telling me why, as a time-nut, that I should love it? As it is, this looks just like many, many, spambots taking over a list. -Chuck Harris hbonho...@freenet.de wrote: hi, I think this story is really awesome, you're gonna love it, please read it here <http://noliledy.X.com/aezon> All the best, hbonho...@freenet.de ___ 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] Have I wrecked my FE-5680A?
We have to sort of conclude that the failure is either caused by bad data getting stored, or some sort of overflow error. It really is pretty unlikely that the firmware has been changed, unless you happened to accidentally start a flash burn routine, and it wasn't qualifying packets properly. If it isn't an overrun, or overflow error, then I would suspect what you are sending to the port. I have worked with guys that are totally flustered when doing firmware for devices that should qualify the data they receive. When they don't know what to do (or are too lazy to try and figure out the right thing to do) they simply stub out the error path and go on. Yuck! If you have been sending an ill formed packet, you best stop doing that ;-) -Chuck Harris Nick Sayer via time-nuts wrote: I'm sending at most a single 9 byte command per second. I currently wait for the TX reg empty flag, which means I'm sending them all back-to-back. I'd have to instead wait for the TX complete flag and then add a delay after that. It's doable, but it would astonish me if 9 bytes in a row were causing it heartburn. I'd love it if there were some way to restore the unit to factory settings / firmware. I'm on the cusp of sending an email to FEI to see if they do anything besides laugh at me. Sent from my iPhone ___ 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] Have I wrecked my FE-5680A?
Likely what is happening is you are overrunning the RS232 interrupt buffer, and that is causing a write into code space. Odd that the firmware is changing, though. Does this thing have Flash RAM, or battery backed NVRAM (Dallas)? Oftentimes, NVRAM using devices use the NVRAM for both firmware, and data RAM space. Things can get really ugly when that is done. Also, to test my guess, put a delay between each character sent to the FE-5680A. Say, 2 or 3 ms. Needless to say before you do this, you need to develop a way of restoring the firmware. -Chuck Harris Bert Kehren via time-nuts wrote: Sadly yes The reason we have not released our GPSDO for the FE5690/50 and FE405 is that we have experienced the same on all three devices. You are the 9th case that I know of. We know very little as to what exactly causes it but we are incorporating circuitry to prevent it. What we know is that it is not a particular code sequence on the RS232 port, but what happens the operating code is turning to mush. Some how the RS port is involved. Serious flaw on all FE devices since most likely the code was written by the same individual. Bert Kehren In a message dated 4/28/2016 9:02:28 P.M. Eastern Daylight Time, time-nuts@febo.com writes: Just as I started testing the GPS discipline board prototype, my FE-5680A seems to have developed a very odd problem. If I give it power, it outputs a “kinda” 10 MHz sine wave while it sweeps around looking for a physics lock. This is as expected. About the time that I would expect the lock light to turn on, instead the output just stops. The lock light never comes on. This unit’s been working fine for months now. It’s conceivable that I’ve sent it some sort of serial command it couldn’t digest, but using the Windows calibrator software seems to work - albeit there not being any output from the oscillator at all. ___ 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] Building a mains frequency monitor
A more modern name for a synchronous motor is a permanent magnet stepper motor. Any PM stepper, and a couple of microfarad capacitor becomes a synchronous motor when connected to the power line. -Chuck Harris jimlux wrote: Alternatively, use a synchronous motor driving a load with sufficient inertia in combination with a slotted disk and photo pickup. Perhaps an old record turntable will do - but not one with a regulated DC motor. A clever idea because of the mechanical low pass filtering, but probably impractical.. A record turntable with a synchronous motor? That's going to be ancient and hard to find in this age of digital music players. People like us would happen to have something in the garage.. but for a science fair project, unlikely that a 6-12th grader would have such a thing, or even know where to find one. *I* have a lot of junk in the garage, and even some synchronous motors, but not one that could directly be connected to the mains. an AC powered rotary dial electric clock, perhaps? (assuming it's not a wall wart powering a "quartz movement".) ___ 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 2010B
Naturally. -Chuck Harris paul swed wrote: Chuck if you do rescan them Diddiers site would be a great location. Regards Paul WB8TSL On Wed, Mar 23, 2016 at 5:11 PM, Chuck Harris <cfhar...@erols.com> wrote: Yes, those are copies of my manuals. I had hoped that Brooke would free them one day, but not so far. I plan to rescan them and release them. -Chuck Harris ___ 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 2010B
Yes, those are copies of my manuals. I had hoped that Brooke would free them one day, but not so far. I plan to rescan them and release them. -Chuck Harris Dave M wrote: There's a CDROM available from http://www.prc68.com/P/Prod.html#Austron that contains a manual for the 2010B, as well as several other Austron models. Don't know if it's just a user guide or a full Op/Svc manual. Email the seller (Brooke Clark) for details. Cheers, Dave M ___ 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 2010B
The 2010B is designed to take a stable reference frequency, 1, 2, 5, 10 MHz, and uses it to discipline its own internal crystal reference. It uses the error information it gathers while disciplining its internal reference to create a model of the internal reference's aging rate vs time. If the stable reference frequency should disappear for a while, the 2010B uses its created model to attempt to correct its internal reference crystal oscillator's aging drift. I find that they perform pretty poorly. I have a copy of the manual, and can scan it... but I am not sure when I will have time. -Chuck Harris paul swed wrote: James Funny I thought that manual would be around also and its not. So it is a disciplined oscillator and thats nice. The question is what does it want to control it. It may be quite a useful unit if as an example it took a 1pps in. But I will speculate it wanted something from the loran c timing receivers. Regards Paul WB8TSL On Wed, Mar 23, 2016 at 12:49 PM, James Fournier <ja...@jfits.ca> wrote: Hello All, I just picked one of these up at a local ham fest. I'm not sure exactly what it was used for. I bought it mainly for the ovenized quartz inside of it. Before I part it out I was hoping to find a copy of the manual so I could determine if it is worth keeping intact. Usually they aren't that hard to find via google but I have had no luck so far. Does anyone have a pdf copy they would be willing to send me? Many thanks! - James ___ 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] I am a nut
Speaking of Wavetek 3000's: They are choc-O-block full of axial leaded electrolytic capacitors made in Mexico. Sad to report that they will most all be bad at this point. Their failure is in the rubber seal for the positive terminal. It allows the capacitor to dry out rendering its bulk capacitance null and void. Electrolytic capacitors marked "Mexico" reached the replace on sight stage a good 20 years ago. The trimmer caps on the reference aren't generally a problem. -Chuck Harris paul swed wrote: Umm Joe. A good sign of a recovering time-nut is to know when to just say "no!". Funny ended up with a wavetek 3000 sig gen circa 1980 if I had to guess. Its main oscillator is 18Hz high. Yes the desire to adjust it is the first impulse. The second is when I tweak that cap all heck is going to break loose. You just know the caps gone bad. So considering what and how I would use it there actually was no reason to foul it all up. Regards Paul ___ 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] OCXO Retrace
I would venture that your unit has a broken SMD part, or a bad solder joint. Try using a wooden chopstick, and lightly pressing here and there, and touching various parts to see what happens. -Chuck Harris Artek Manuals wrote: To further underscore Charles point and to add another dimension to the discussion.,The Z3801A that I have been working to bring back from intensive care in the last two weeks is sensitive to a very slight mechanical shock. The unit was laying open on the bench with all kinds of test clips hanging out of it (power IN and monitor of the various DC supply busses). At one point I slightly repositioned the Z3801 and in doing so "dropped" (front edge only ) about 1/4". Nothing scary but a noticeable THUMP. Less than a minute later I noticed that the PPS error began drifting lower and over the next 30 minutes stabilized almost 200ns low. At that point I powered it down for 5 minutes and then ran a survey again and it was fine . I repeated the little experiment a couple off times and each time it received a "thump" it started drifting low. Simply left alone over a period of several hours it would return to center around 0 pps on its own. The moral I took away from the little experiment was to make sure the Z3801A's final resting place on the bench when it gets out of the hospital and returns to work was in a low traffic - "quiet" location where it would not get bumped. Dave NR1DX On 2/11/2016 12:16 AM, Charles Steinmetz wrote: Bob wrote: I'll see if I can figure out which of these is retracing the "wrong" way and put it in a unit. I'll let it cook for a couple of days and then post a plot. Like I said, these are all Trimble 34310-T, though I know that there were at least two manufacturers for that part number. They were all positive EFC devices with more or less the same frequency range. I would expect all OCXOs with the same part number to have the same type of crystal (though maybe not from the same manufacturer), so they should all be the same (within some distribution around nominal) WRT the *warmup* drift. As to the actual (post-warmup) *retrace* drift, there is no right or wrong direction. If you let an OCXO go cold 100 times, wait a day or more (each time), and then power it up, it will likely retrace up sometimes and down other times. One of my 10811s pretty much alternates from one cold start to the next (but I very rarely power it down). Once again, crystals are very individual devices with very individual personalities, and they are often unpredictable. They are made to be powered up and left undisturbed for months/years/decades. Use them that way, evaluate them that way, and don't waste time puzzling about what they do for the first month after you power them up. It does not make any sense to power them on and off "rapidly" (off for less than a week, on for less than a week) and try to draw conclusions about anything that matters with respect to their performance. 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 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] Valpey-Fisher VFT22H OCXO Output
Looks like the output of a simple single ended emitter follower that isn't being loaded properly. Try again, but this time with a 50 ohms load. -Chuck Harris Logan Cummings wrote: Hi All, Curious what could give this waveform (attached) - I presume this is not correct output for this oscillator (surplus/salvage from Harris Constellation receiver). Frequency looks OK with +2V EFC but output looks like neither sine nor any CMOS I've seen into 10Mohm (first capture, scope probe alone) or 50ohm (50ohm term at SMA connector, probed by same scope probe) . What gives? If I open up the can, what am I looking to possibly replace/eliminate? How to open it? It's soldered shut (2x2in case). I need a good low-noise 100MHz sine wave for my application so I'm tempted to open this guy up and replace the output circuitry with something more suitable. Thanks in advance for any pointers/info on these units! -Logan ___ 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] low noise multiplication to 100 MHz
Back years ago I was a dealer for Aoyue rework stations, so I use one of those. They are all knockoff's of Hakko stations, and frankly any that has a servo'd heat source would do nicely. What I sold had a digital temperature control, and a flow meter to show how fast the air was flowing kind of important to know, but you can wing it easily enough. There are scads of special tips available for all sorts of different package types. For small stuff, I use the smallest round air nozzle... which is about 1/8 inch. If I am doing a large QPF package, I will often take the time to put the right manifold/nozzle on the unit. It depends a lot on whether I am just scrapping parts off of a board, or am trying to save the part/board. Under board heating is very important to your success. Back when I sold Aoyue, they were going for about $230, which was pretty reasonable. You can get them direct from China cheaper than that... which is why I don't sell them anymore. -Chuck Harris Bryan _ wrote: Chuck, what do you use for a hot air source. The good ones are very expensive. Wonder if there is something for the hobbyist. Have seen a few repair videos where they used just used a hot air stripper. I had to yank a couple SMD resistors off a board the other day and had to use two soldering irons at each end of the resistor . If they are small enough you can add a glob of solder to the whole resistor, so both ends will melt. Cheers -=Bryan=- ___ 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] low noise multiplication to 100 MHz
Hi Bert, I have noticed that if I have the right magnification, I can do amazing things. Even the tiny age related tremors that naturally occur in my hands reduce with magnification. The brain is a marvelous servo mechanism. Get a good 40x-80x zoom stereo microscope meant for dissection, the type mounted on a boom, and I would bet you too could deal with the small surface mount parts. When I build with SMD, I always put all of the parts on the top side, and use solder paste. I used to put lots of tiny dots out with a syringe that works a lot like a caulking gun... only smaller. But I found that simply drawing a thin stripe of paste across the SMD pads on the board, and then setting the part on the paste, works just fine. The solder draws towards the pads, and leaves the space between the pins clear. Occasionally there will be some tiny balls sitting between the pins, but they clean up when I clean the board with alcohol and a brush...not that they hurt anything anyway. The chips self center while they are floating on the molten solder. No need to touch them with a soldering iron, or anything else. I use a lab grade hot plate to bring the board up to reflow temperature. And I am off to the races. For disassembly, I use an IR underboard heater, and a hot air source... about 1/8 inch diameter, and move it around the pin area until it melts, and then lift the part free. To put parts on an already populated board, I pre heat the underside of the board to about 1/2-2/3 the way to the solder melting temperature, and use a little gentle hot air source to head the pads the rest of the way to molten. No need for soldering irons. Practice on junk boards until it becomes natural. -Chuck Harris Bert Kehren via time-nuts wrote: We have looked at the LMK devices but with my 74 years would not try to solder it. There are other neat parts out there but again who is able to solder them. Bert Kehren ___ 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] low noise multiplication to 100 MHz
One last post on this off topic subject: Eyes. The younger folk will think eye problems amount to near or farsightedness... maybe a little astigmatism. The slightly older folk (37+) will know about presbyopia... the loss of your close working focus... your arms get shorter. Then there are the 60+ folks who know about a whole new spectrum of problems. For you the macular degeneration, for me the detached vitreous humor from my retina. These result in holes in the vision, or ghosts and shadows that float into and out of view. Fun! Microscopes cause problems with the 60+ kinds of vision problems because they hold the eyes steady, and accentuate the floaters and holes. You can't just shift your eyes and look around them because the scope needs each eye to be accurately fixed on axis with the optical path for it to work. Fortunately there is a way out of this problem, and it is a pretty cheap one too. The little CCD or CMOS video camera, and an LCD monitor. This allows your eyes to look up, down and around on the screen, and you get the needed magnification, but because of the way your brain works, you won't notice the floaters, and macular holes... You just look around them, and your brain fills in the gaps. You do lose your stereo optic distance clues, but there are more expensive ways of correcting that too. The more expensive solution is the Mantis, a large flat screened stereo optic microscope that is supposed to help provide the distance clues. I haven't used one, but I have heard good things from those that have. Not exactly cheap, but getting old has its costs. You can work in SMD electronics when you get old. -Chuck Harris Bert Kehren via time-nuts wrote: Chuck Thank you for your advice, I will print it out and when needed experiment. We use SMD.s and two of our tem members are very good at it, I do limited stuff and have some tools but also a macular hole in one eye. In designs I try to stay with solder able SMD's and we have projects like the AD9913 which gets to the limit what I will consider. I did not do the soldering. Bert ___ 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] Timelab, two SR620s and losing samples
Talk-only mode is by intention, an exclusive mode, where there is one talker, and one listener on the bus. There can be exceptions where there are more than one listener, but that tends to be unusual. Addressed mode can have one or more instrument on the bus. Although addressed mode is fully orchestrated by the controller, the controller can easily interleave things in a way that can cause unintended latency in a critical instrument. -Chuck Harris Magnus Danielson wrote: Poul-Henning, On 01/17/2016 12:52 PM, Poul-Henning Kamp wrote: In message <569b61cf.3030...@rubidium.dyndns.org>, Magnus Danielson writes: This is a common misunderstanding: Talk-only does *not* protecting you against timing issues on GPIB. On RS-232, yes, but not on GPIB. Agree, to some degree. It's not a guarantee. I think you should develop that line of thought, to detail why it helps on GPIB and why not on serial. It's really very simple: RS-232 sends blind, you don't even need to know if there is a receiver or what it does. If the receiver cannot keep op, data is simply lost. GPIB handshakes every byte, so the actions of the receiving end affects the transmitting end - in particular if the receiver cannot keep up. ___ 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] Lady Heather Server On Raspberry Pi 2 Model B?
Hi Mark, That was well understood when I stated that your life would have been easier had QT been used. It would have... DOS was a real pain for doing mouse and graphics stuff. QT makes it easy.. But QT would have also slowed a DOS era processor to a stop, and it would probably still be trying to refresh the screen ;-) -Chuck Harris Mark Sims wrote: Lady Heather predates QT by several years... actually back to 1985 when her mommy controlled Magellan GPS receivers. A version ran on HP95LX palmtops during the first Gulf War. The server option just uses the server program to connect the GPSDO serial port to the net. On the other end Lady Heather uses the TCPIP connection data like it came from a serial port... so you need a Windoze box to run Lady Heather and display the data. ___ 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] Lady Heather Server On Raspberry Pi 2 Model B?
If you stick to something like QT4, which is either python, or C++, it is rather easy. QT4 has everything set up for you already, and a compiler for the graphics screens. You create the basic screen in the designer, and tell it what you want it to do when a mouse hovers, clicks, drags, etc... and it does it. QT4 also has all of the fancy graphics routines you could imagine wanting... including routines to plot graphs, polar, linear, log, bar... whatever. Tons of tutorials are available on line... as are lots of complete projects... open source and all that. QT4 is oriented towards C++, but it has been ported to python. This opens up a broad world of mathematical and plotting libraries, as well as USB, IP stacks, printing routines, everything. The big problem is the tutorials are for C++, and there are some pretty significant differences between C++ and python. Life would have been 1000% easier for Mark and John if they had used QT4 in the first place Especially Mark, as his original work was for DOS, which needed extreme hand holding for every little thing. The biggest problem I found was not getting totally confused by the extreme number of #ifdef statements that made it work on this, or that variation of DOS, 'Doze, debug... -Chuck Harris Mark Sims wrote: I wonder if I've got anywhere near the skills to do it... Probably not right now... it's not so much as knowing C, it's knowing the ins and out of knowing how your operating system (Windows, Linux, etc) interfaces with your hardware (display, mouse, serial port, keyboard). Basically, if you have to ask the question, your are probably not ready to attempt the task. Lady Heather is a pretty simple program, but it is rather long and divided into 5 files. Just getting set up to compile it in a new environment can be quite a challenge to the un-initiated (acouple of toupees worth of hair pulling once you can compile and link a simple "hello world" program. Then you need to figure out how to draw dots and characters, talk to the serial port, talk to the mouse, talk to the keyboard. Pretty basic stuff once you are familiar with your operating system/environment, but not something most people do everyday... ___ 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] Lady Heather Server On Raspberry Pi 2 Model B?
Unfortunately, LH uses a graphics toolkit that was written by John Miles, and it, and he, is windows only. I got started on converting it to PyQT4, but got side tracked. Maybe this year is the year I get all of the stuff I have promised done? -Chuck Harris Ed Armstrong wrote: Has anyone successfully ran Lady Heather Server On Raspberry Pi 2 Model B? As it's not an x86 architecture processor, I assume Wine is no use and a custom compile is needed. Am I correct? Can any of you suggest where I can learn to do that, I'm rather new to Linux. Thanks Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] Lady Heather Server On Raspberry Pi 2 Model B?
LH is an excellent program, and it needs to be brought into polite society, by making it run natively on all platforms. Changing it to Python, and PyQT4, is easy, but there is a lot of code base to sift through. Once on Python, and PyQT4, it will run natively everywhere. Including smartphones and tablets. -Chuck Harris jim s wrote: On 1/9/2016 6:36 AM, Chuck Harris wrote: Unfortunately, LH uses a graphics toolkit that was written by John Miles, and it, and he, is windows only. I got started on converting it to PyQT4, but got side tracked. Maybe this year is the year I get all of the stuff I have promised done? -Chuck Harris Ed Armstrong wrote: Has anyone successfully ran Lady Heather Server On Raspberry Pi 2 Model B? As it's not an x86 architecture processor, I assume Wine is no use and a custom compile is needed. Am I correct? Can any of you suggest where I can learn to do that, I'm rather new to Linux. Thanks Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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. Depending on the executable, wine runs on ARM. YMMV. http://wiki.winehq.org/ARM Qemu and Dosbox run quite a lot of things I have on Raspberry Pi, and other ARM SOC's that I have. Thanks Jim ___ 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] Springer textbooks >10 years old now available fordownload as PDF at no cost
Seems to me that there was a court case where Springer was ordered to follow through on its promise to release all books and academic papers to the public domain after something like 5 or 10 years. Anybody else remember anything like that? -Chuck Harris Bob Camp wrote: Hi Actually it looks like the party is over. At least from here in the US, when I go to the original links, they will only sell me the book. No more free downloads. It was fun while it lasted …. Bob ___ 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] SMD TADD-1 distribution amplifier - seeking comments and suggestions?
One of my other hats involves advising electronics scrap and recycling companies, and the repair of all manner of electronics equipment. In all of the equipment I have rummaged through I can state the following without reservation: I have never seen any sign of damage caused by properly float charged sealed lead acid batteries. I have seen lots of serious damage caused by trickle charged nicads. I have seen some very serious damage caused by lithium iodide pacemaker cells at end-of-life. I have seen lots of damage caused by carbon-zinc, and alkaline cells. Lithium ion cells behave like electrolytic capacitors. They want to have their initial inrush current limited to about 1C, and they must have their final charge voltage limited to 4.2V. They will tolerate being floated at 4.2V for quite a while, but that will ultimately lead to their capacity being compromised. A simple backup charger for a LiIon cell would be a constant voltage, current roll back supply that is controlled by a timer that charges the cell every time power is restored, and several times a year if power doesn't fail. Discharge must be abruptly stopped when the cell voltage drops below around 2V... the exact value varies by the manufacturer. -Chuck Harris Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 17 Dec 2015 21:00, "Anders Wallin" <anders.e.e.wal...@gmail.com> wrote: First prototype assembled today, tested with 12 VDC SMPS wall-wart supply and with 12 V lead-acid battery. Anders Is the lead acid battery supposed to be there so the unit continues to function if power is removed? If do, I believe that the choice of a lead acid battery is a poor one. I believe that even the sealed ones release very small amounts of sulphuric acid and when contained in equipment the acid results in damage in the long-term. I believe that people have reported damage to oscillators like the HP 10811A even on this list. I believe NiCd would be a better choice. That said I somewhere read they were banned in Europe but that might have been for general consumer use, as I note that they are still shipped in some products - e.g. sone emergency lights I bought in the UK from Farnell, although the lights were made in China. One can certainly still buy NiCd cells in Europe. I don't know if there is any simple way of slowly charging Lithium Metal Hydride batteries. Commercial chargers from reputable manufacturers have temperature sensors, voltage sensors and I assume a microprocessor to determine how to charge them and when to stop charging. You don't need to fast-charge a distribution amplifier, but I don't know if there's any relatively simple way of charging them. 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] Mechanical clock sound pickup circuit
Let's be serious here. Radar is the wrong part of the E-M spectrum. Use light. It is cheap, easy to detect, and there are plenty of reflections to go around. Or better still, listen to the tic. Then you don't even have to open the case Which brings this full circle. -Chuck Harris Jim Lux wrote: On 12/14/15 9:12 PM, ed breya wrote: This may be totally ridiculous, but maybe there's another way to get a balance wheel signal. The X-band Doppler type microwave motion detectors can pick up various object signals in free air from quite a distance, so maybe up close there would be enough resolution and penetration of the metal parts of a timepiece to get a usable signal in and out. It would tend to accentuate the fastest part of any motion - the balance wheel in this case. I can picture setting one up with the horn pointed at the thinnest part, likely the watch face, from maybe a few inches away - or whatever it takes to not overload the detector. The audio detector signal (if sufficient) could then be processed in the same way as with a microphone sound signal. As it happens, I have a fair amount of recent experience detecting small (<1mm) motions using radar. Yes, remarkably tiny holes will let enough signal in and out, but, it's going to be very, very position dependent. You have a lot of multipath in this kind of testing, and it's easy to wind up in a null zone. You might want to look for K-band (24GHz) units: the shorter the wavelength, the more phase shift you get from the tiny motion. To put some numbers on it: at 3 GHz, a 1mm displacement gives you about 6-7 degrees; at 24 GHz, you're going to be getting 50-60 degrees. You'll be wanting some form of homodyne detector (which has the nice property that the phase noise of the source cancels out, so you can have a pretty grungy quality oscillator). The signal you're looking for, though, is phase shifts occurring at a 1Hz kind of rate. Most of the cheap "motion detectors" have a high pass filter (1 m/sec at 3 cm wavelength is 66 Hz) and the amplifier chain is AC coupled. You'll need a good low noise amplifier with a low 1/f knee. For reference, a receiver gain of about 60 dB gives you a millivolt kind of signal from a 1mm displacement with 1mW at 3GHz from a 0.1 square meter target at 10 meter distance. You can scale to your situation. You'll probably want some way to subtract out the static baseline, so your high gain amplifier stages don't need enormous dynamic range. In my radars, I do this with an adjustable "leakage" path from Tx to Rx. You could probably do it with a movable metal target next to your clock/watch and you adjust it for a null. You probably also want a I/Q output: if you think about the signal you're receiving, it's a slowly moving vector that spans a fairly small phase angle (because it combines a very large static response from stuff that's moving plus a little tiny moving component). If that vector happens to point at 90 degrees to your I axis only, then you're great: the variation shows up in the I axis. But if the vector happens to point parallel to the I axis, the motion is very small. With I/Q, you can either do a arctan demodulation, or you can rotate the signal to make the variation largest (basically using the sin x=x approximation for small x) Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] Mechanical clock sound pickup circuit
Back in the day, companies, like Vibrograf, Greiner, Elna, L, all made timing machines that were based on the same principles. The machines used a crystal, or tuning fork frequency reference, and divided it down for the various standard (and not so standard) watch beat rates. The divided reference signal was used to turn a synchronous motor, which rotated a drum which had a single turn loop of wire wound around it, in the fashion of a "one turn per drum width" screw thread. The watch's movement was clamped into a mount that had a piezoelectric element, usually a rochelle salt crystal, that turned the small vibrations into an electric representation that was fed to a chain of amplifiers, filtered to amplify only the audible component until it was large enough to trigger a tiny little thyratron tube. The thyratron tube was set so that when the impulse exceeded a variable threshold, it would fire, and would discharge a capacitor into a solenoid for an instant, and pull in the armature that caused a metal "bale", that was as wide as the drum, to strike the wire that is wrapped around the rotating drum. Because this wire essentially proceeded along the drum as it rotated, the intersection of the wire, and the bale formed a scanning element, not unlike the beam on a CRT oscilloscope. To record the impulse, a paper tape was fed between the rotating drum, a typewriter ribbon, and the metal bale. When the metal bale "ticked", it pushed the ribbon against the paper, and the travel was stopped by the rotating wire wrapped on the drum, and an ink mark was made. Ok, why all this complexity? The idea was to, tick-by-tick, record the difference between the watch movement's escapement's noise and the smooth flow of time embodied by the crystal/tuning fork/dividers, etc.. By adjusting the gain of the microphone's amplifier stage, and as a result, the threshold of the printer, the watchmaker could observe quiet repeating noises all the way down to the pretty noisy tick of the watch. When you look at these actual traces, your squishy ware's DSP can easily see the slope of the group of traces, which is the rate of the watch, and any rhythmic variations of the individual "ticks" recorded on the paper. You can see things like irregular spacing of the teeth on the escapement wheel, and irregular spacing of many of the later wheels and pinions. By adjusting the gain of the amplifier stages, and the resulting shift in threshold, you can select out noises of different loudnesses. And the speed of the thyratron, and charged capacitor allowed multiple strikes of the bale during each tick. You can see the noise made by the impulse jewel touching the tuning fork, and the noise made by the pallet jewels touching the escapement wheel... Lots of very interesting things that indicate the quality of the movement, and the state of its lubrication... as well as a nearly instantaneous indication of the rate of the watch, as it sits in the various "positions" (dial up, dial down, pendant up, down, right left...) All of this from the feverish minds of horologists back at the dawn of the vacuum tube. I would suggest that any programming you use for your tools do similar things. -Chuck Harris Andrea Baldoni wrote: Hello! I decided to do some experiments with mechanical clocks, so I worked a little on picking up escapement ticking sound, with the idea of processing it and obtaining a "clean" digital pulse to feed a counter. So far, I have not yet been able to find the best way to obtain a digital pulse, but I have already built the preamp for the piezoelectrick pickup, that I used to feed the mic input of a PC sound card for spectrum analysis. The timing could eventually be done in software because the whole idea of measuring watches by picking up their noise almost surely doesn't allow high resolution anyway, but I will plan to try hardware solutions as well in the future. I hope to be able to measure the jitter of the clock, but it will be very hard. In the meantime, with the free software Biburo you can download here http://tokeiyade.michikusa.jp you can regulate your wrist watch. Best regards, Andrea Baldoni ___ 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] RG 6 U couplings
I wouldn't get too hung up over fire rating on such cables. Your house and shop is littered with PVC cabling that will make lots of nice toxic smoke if it burns. Fire rated cable, also known as plenum cable, is special because it is meant to be run in the ducting spaces for the HVAC system in a commercial building. In most commercial buildings, the entire raised ceiling area is the intake duct for the building's HVAC system. Because air is moving pretty rapidly in the intake plenum, it tends to feed a fire, and when a piece of wire in an air plenum burns, it will burn from one end to the other, spreading the fire and making lots of smoke Which, being in the air intake for the building will spread to everywhere there is an outlet duct... If you are planning on running the wiring in your HVAC air ducts, then by all means use plenum wire, but anywhere else in your house/shop is a waste. Burning teflon wire has its own plethora of problems. -Chuck Harris Mark Spencer wrote: I looked up the part number of the cable I installed and the data sheet says it does have Teflon insulation. It does look different than other Teflon cables I have seen though. My main concern was and is the fire rating. The comments about the phase stability are also of interest. If anyone has this type of data for RG 6 style cables I'd be interested in seeing it. If I ever run new cables to the roof I might pull an new run of rg6 for the GPS. At one point I was looking at ways to safely route non fire rated hard line to my GPS receiver. Sent from my iPhone On Dec 7, 2015, at 6:33 PM, Hal Murray <hmur...@megapathdsl.net> wrote: m...@alignedsolutions.com said: Actually I may be misremembering this.Am not sure if the cable I used was Teflon on not. It did have a defined fire rating though, and I was concerned about it's phase stability vis a vis temperatures. I was at Xerox in the late '70s when the DEC-Intel-Xerox work on Ethernet was going on. The Los Angeles fire dept was sensitive to smoke from cables. A friend got a chunk of potential cable from Belden. It was Teflon coated. I don't know what was inside. He took it out on his back porch and hit it with a propane torch. It ignored him. Well, not quite. It got smudged a bit, but that wiped off. He took a bigger chunk to Underwriters Lab in Chicago. They have a setup for testing cables. It's a cable tray in an enclosure that's 20 ft long and a few feet wide and 3 or 4 feet tall. A big gas pipe goes in one end. There is a chimney at the other. They put the cable in, replace the lid and light it up. The Teflon cable didn't have any problems. Teflon is expensive. After a couple of years somebody worked out a cheaper compound that was good enough for the fire people. -- These are my opinions. 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] RG 6 U couplings
I use mostly Quad RG6, and I use the Ideal ratchet crimper and fittings as are available from Lowes, or Home Despot. It is important to note that RG58 <> RG6 <> Quad RG6. They are each different in diameter, loss, and shielding capability. Each needs a different sized "F" connector, and crimping die. Fortunately the Ideal crimping die has all three sizes. -Chuck Harris F. W. Bray wrote: For those of us in the U.S., does anyone have suggestions of vendors or brands of quality connectors and installation tools? Over the years, I worked my way up from cheap wire terminals to PIDG connectors and the correct tools. Rather than repeat the process with F connectors, I'm willing to pay a bit more the first time to do it right. Fred KE6CD ___ 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] RG 6 U couplings
Real RG58 has a copper wire shield. Real RG6 has a copper wire shield. RG58 and RG6 tend to leak RF a bit. Real Quad 6 has aluminum foil and aluminum wire shields. Quad 6 was designed to use multiple layers of grounding shield to prevent this leakage. RG6 should have the same foam center insulation as the Quad, only it should have fewer shield layers. -Chuck Harris Hal Murray wrote: cfhar...@erols.com said: It is important to note that RG58 <> RG6 <> Quad RG6. They are each different in diameter, loss, and shielding capability. Is the attenuation of RG6 significantly different from Quad RG6? I'd expect the loss to be primarily determined by the size of the center conductor which would be the same. ___ 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] Einstein Special on PBS
The whole "t" thing was bothering me in John's explanation, so I
showed it to my son the physicist. He tells me that John's
explanation comes from Brian Greene's book, "The Elegant Universe"...
A very popular coffee table book, aimed at the same market as those
by Stephen Hawking.
Greene's explanation breaks the 4 known dimensions of space into
X,Y,Z, and C*T That arbitrary multiplication of time by the
constant C forces all four dimensions be in terms of distance.
In the internet traffic where people seem to spend a lot of time
discussing this model, it is common to forget that t is really C*t,
and say silly things like the velocity of t in meters/second...
Additionally, the dt/dt =0 thing needs the "t"'s to be different,
say "t" and Tao. where Tao is the time on the moving frame, and t
is the same time as viewed from the stationary frame...
There are lots of reasons why one might want to simplify a set
of equations by multiplying by an arbitrary constant, and then
factoring it out later... It might make the math easier, but it
also can completely change the model you are working on.
According to my son, that "simple" explanation confuses things more
than it helps if you are actually doing physics, but does tend to
make an intuitive feeling for special and general relativity available
to the unwashed masses.
-Chuck Harris
Didier Juges wrote:
Wow. So elegantly simple explanation, thanks John!
On November 27, 2015 2:54:51 PM CST, John Miles <j...@miles.io> wrote:
So, here's how I finally grokked this stuff. c, the speed of light in
a vacuum, is often spoken of as a "speed limit" that nothing can ever
exceed. That's a bad way to put it, and people who have expressed it
that way in popular science writing for 100 years should feel bad.
Instead, the way to visualize relativity is to realize that c is the
*only* speed at which anything can travel. You are always moving at
300,000,000 meters per second, whether you want to or not. But you're
doing it through all four dimensions including time. If you choose to
remain stationary in (x,y,z), then all of your velocity is in the t
direction. If you move through space at 100,000,000 meters per second
in space, then your velocity in the t direction is 283,000,000 meters
per second (because sqrt(100E6^2 + 283E6^2) = 300E6.)
It doesn't make sense to speak of moving a certain number of "meters"
through time, so your location in time itself is what has to change.
You won't perceive any drift in your personal timebase when you move in
space, any more than you will perceive a change in your location
relative to yourself. ("No matter where you go, there you are.") But
an independent observer will see a person who's moving at 100,000,000
meters per second in x,y,z and 283,000,000 meters per second in t.
They see you moving in space, in the form of a location change, and
they also see you moving in time, in the form of a disagreement between
their perception of elapsed time and your own.
Likewise, if you spend all of your velocity allowance in (x,y,z), your
t component is necessarily zero. Among other inconvenient effects that
occur at dt/dt=0, you won't get any closer to your destination, even
though your own watch is still ticking normally. Particles moving near
c experience this effect from their point of view, even while we watch
them smash into their targets at unimaginable speeds.
This is special relativity in action. The insight behind general
relativity is twofold: 1) movement caused by the acceleration of
gravity is indistinguishable from movement caused by anything else; and
2) you don't even have to move, just feel the acceleration. That
second part was what really baked peoples' noodles. It is what's
responsible for the disagreement between the two 5071As.
-- john, KE5FX
Miles Design LLC
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Re: [time-nuts] Einstein Special on PBS
Or, you could just stay at high elevation for a longer period of time and make the travel time less significant. -Chuck Harris Arthur Dent wrote: Tom wrote: "I'll make just a one word correction to your summary. The clocks run a bit faster not because of "the spinning earth" but because of "the earth"." You are correct, I misspoke. While that point may have been wrong I did check the elevation of Mount Sunapee and it is indeed at 2726 feet as measured by USGS and others. When I posted before I 'assumed' the researchers were from MIT or one of the Boston area schools (or UNH) and would therefore be at sea level. Rewatching the video they do say that the second clock is at sea level but they don't mention where they are. The drive up to the base of the mountain would probably be 1 to 1.5 hours so the 1st clock didn't go from sea level to 2726 feet instantaneously so during that travel time it was probably at an average of about 500' which is near the average elevation in New Hampshire. If the experiment had been conducted in the Burj Khalifa in Dubai, United Arab Emirates and the elevator could go from sea level to about 2000 feet, which may be the top floor, the experiment might be more exact because you'd eliminate the travel time. -Arthur ___ 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 "osc age alarm", where to get replacement oscillator?
Typically all that means is the crystal needs to have its trimmer capacitor adjusted back into range. I have no direct knowledge of the TBolt's oscillator, but it might be as simple as removing a screw, and adjusting the trimmer... Or, in some cases you have to remove a solder blob from the metal can, and access the trimmer. I would sure hate to toss away all that hard earned aged xtal for a new one at this point. -Chuck Harris Pete Stephenson wrote: Hi all, Lady Heather just reported that my Thunderbolt's "osc age alarm" just activated. The manual tells me this means that the oscillator control voltage is at a rail and that the oscillator should be replaced. It says this shouldn't be needed during the first 12 years of service, but mine is ~17 years old, so its time may have come. Where can I find a suitable replacement oscillator? Is there a recommended part number? If the original part is no longer available, what is a good substitute? Cheers! -Pete ___ 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] NAVSTAR proteus GPS time and frequency unit
Magnus, Thanks for the detailed reply. I haven't had a need (read: no customer has paid me to do so...) to wallow through the GPS ICD, so that document is foreign to me. Your explanation clarifies the situation... Now it makes sense. Thanks! -Chuck Harris Magnus Danielson wrote: Chuck, Because all the leap-second info is kept in GPS-calender form, and essentially indicating current leap-second difference and which GPS week (modulo 256). Check out the ICD for yourself, IS-GPS-200H: 8<--- 20.3.3.5.2.4 Coordinated Universal Time (UTC). Page 18 of subframe 4 includes: (1) the parameters needed to relate GPS time to UTC, and (2) notice to the user regarding the scheduled future or recent past (relative to NAV message upload) value of the delta time due to leap seconds (ΔtLSF), together with the week number (WNLSF) and the day number (DN) at the end of which the leap second becomes effective. "Day one" is the first day relative to the end/start of week and the WNLSF value consists of eight bits which shall be a modulo 256 binary representation of the GPS week number (see paragraph 6.2.4) to which the DN is referenced. The user must account for the truncated nature of this parameter as well as truncation of WN, WNt, and WNLSF due to rollover of full week number (see paragraph 3.3.4(b)). The CS shall manage these parameters such that, when ΔtLS and ΔtLSF differ, the absolute value of the difference between the untruncated WN and WNLSF values shall not exceed 127. Depending upon the relationship of the effectivity date to the user's current GPS ... ___ 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] NAVSTAR proteus GPS time and frequency unit
Seems to me that there is more to this than just getting the displayed date wrong. It is true that the date will present wrongly, but what about leap seconds? If the GPS week rolls over at 1024, how will the GPS figure out which is the proper calendar date to apply the leap second? -Chuck Harris Hal Murray wrote: paulsw...@gmail.com said: Hmmm then why do I have to figure it out at all? I don't care what the date says. Only that the Austron locks and does its frequency offset compare. It would be great not to have to do this. If you don't care about the date, then don't worry about it. It will do everything it did before. The only glitch is that the date will be off by 1024 weeks. If you can't get the right date into your GPS unit, you can work around the issue in software. Just add 1024 weeks to the date until the date is past the build time of your fixup software. That assumes you have some software to work with. That won't help if you are using a program that the vendor no longer supports. ___ 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] HP 53131A display dim
The biggest cause of failure with VFD's that I have seen is the filament voltage drops too low. Usually it is a bad capacitor in the supply, or a drifting resistor on the regulator. I have a VFD on an alarm clock made by GE back in 1980 that has been running 24/7 since it was bought, and is still way too bright. I make my wife prop something to block it so that it doesn't keep me awake. -Chuck Harris cdel...@juno.com wrote: Anyone know about these displays? If the display is getting dim do I need a new VFD module? Thanks, Corby ___ 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] 10811 unsoldered fuse
That's not missing, that's something that happened after it left the factory. Look at the coloration of the traces near that joint, and the solder residue on the lead. Look at the cold looking solder joint on the toroid next to the black wires. Look at all of the solder splash. I would say that board has been worked on by a technician... and not a very proud one at that. -Chuck Harris Dimitri.p wrote: How common is it to find undetected missing solder on 10811 parts after all these years? Dimitri ___ 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] 4046 experiment for gpsdo
You missed the part about the 10MHz being divided by 10 million to produce a 1PPS signal that is compared to the second 1PPS signal... -Chuck Harris Will wrote: Hi, I'm new and trying to get to grips with things. If I understand correctly, please forgive if I have it wrong, This locks a 10MHz signal to a 1Hz (1pps) signal. What makes it lock to 10 000 000Hz instead of 999 999Hz or 10 000 001Hz? Just the hope that the 10MHz is exactly that? Cheers, Will On 26/09/15 08:32, Jim Harman wrote: To further demonstrate the Diode - R- C- approach, here (hopefully) is a screenshot of the raw DAC output vs time on my Arduino Micro (32u4) based system. For this test the oscillator is free running with an error of about 1 usec per 460 sec or 2.17x10^-9. The horizontal scale is 125 sec/div (1000 sec total) and the vertical is 1024 DAC counts (0-2.56 V) which corresponds to 1 usec of offset between the oscillator and the reference. You can see that there is some curvature because the capacitor is being charged through a resistor and not a true current source, but as I mentioned earlier this does not affect the system's ability to lock the oscillator to the pps reference. When locked with a time constant of 1000 sec, the phase detector output is almost always less than +/- 100 counts from the setpoint of 500. The noise is due mostly to jitter in my PPS reference, which is generated by an Adafruit GPS module. Presumably it would be less if I had a real timing receiver. . If the inserted image does not come through, I will re-send as an attachment. -- --Jim Harman ___ 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] Subject: Subject: Re: HP5065A C-field current voltage mod
Are you sure? Perry was proposing to use a TL431 to make an oven, using its famous temperature sensitivity, and inside the oven would be another TL431 that acted as a voltage reference. Every oven I have ever seen that is temperature controlled has a part that is quite good at measuring temperature at the helm. -Chuck Harris Poul-Henning Kamp wrote: In message <1530394039.1439027.1441348869239.javamail.ya...@mail.yahoo.com>, Pe rry Sandeen writes: OK, but why? The temperature would be stable so the resistorsand reference diode wouldn't drift. No, the temperature is not stable, not even close. Given that the TL431 is quite good at measuring temperature, that makes it unsuitable in this case. I have identified one source of the temperature fluctuations: The series pass transistor of the +20V rail is located right beneath the A15 PCB, so any variation in mains (or EXT DC) voltage causes the A15 temperature to change accordingly. More details here: http://phk.freebsd.dk/hacks/HP5065A/20150903_psu/ ___ 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] HP5065A C-field current is temperature sensitive
Hi Bob, I haven't seen anyone bashing the designer, or the design of the 5065. What I have seen a couple of enthusiasts that love the unit enough that they are willing to spend countless hours bringing a couple of parts of the design up to a more recent state of the art. Corby's modifications to the optics added stability that no one anywhere has achieved in a Rb standard. PHK's changes to the oven may achieve a similar improvement. Between the two of them, the 5065 is looking pretty nice! In my experience, there are quite a few pieces of equipment where people are willing to take the relatively minor effort to repair them to match their original specifications, but very few where people are impressed enough with the foundation parts that they are willing to spend the great amounts of time it takes to fully understand and modernize the design. I think that speaks well for the designers of the 5065. -Chuck Harris Bob Camp wrote: Hi As we go joyously bashing the poor guys that designed this beast, it’s worth noting just how old the design is. 741 op amps were indeed “modern” when they did much of this and quite possibly to modern to be trusted. Most of the design would have been right at home in the late 1960’s at a conservative design house. As time has shown, in a lot of cases that mistrust of the early linear stuff was well founded ….The 741 only was designed in 1968….The 5065 design dates to roughly that time. Bob ___ 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 oven repair info for HP 5065A
The main oven on my 5065A was made with a bifilar winding of enamel covered nichrome wire wound directly on the aluminum oven. To cancel the magnetic field, the far end of the coil was shorted, making the heater a hairpin loop No twist that I recall... The enamel was compromised somewhere along the winding, causing it to put the oven into thermal runaway, thus toasting the lamp assembly. (this was my first exposure to how stupid HP could be with some of the designs they made...) The runaway oven got hot enough to reflow the solder, and cause several parts to fall out of the lamp's circuit board... the board was turned into just plain old fiber glass matting, as all of the epoxy... or whatever it was, turned to charcoal. When I did this stuff, I was fresh out of EE school, the web didn't yet even exist as an idea, and I knew nothing about how rubidium standards worked I knew they were special, so I called up HP, and ordered a $300 manual... but I digress... My first fix was to disassemble the oven, and wrap it with a solenoid of teflon insulated heating wire. It worked nicely, except that it made a magnetic field, and shifted the frequency with temperature.. Whack!... DOH! Next, I found some thin coaxially shielded nichrome wire meant for I know not what... maybe electric blankets? And put a crimp on connector at the far end to make a coaxial hairpin loop. I tightly wound that around the oven, and used great stuff urethane foam to replace the oven's insulation. It worked quite well, until the next thing went wrong, and I put the reference on my to be fixed someday shelf where it has lived ever since. Back then, I didn't know anything about capacitor plague, and carbon composition resistor drift, and all the usual failure modes of HP equipment... I ought to take it off of the shelf and give it a go once again... should be easy... for an engineer that now has 35 years more experience... Right? -Chuck Harris cdel...@juno.com wrote: Hi, Just thought I'd share some info on repairing a defective HP 5065A lamp oven. These ovens can fail either shorted to the oven cylinder or have interwinding shorts. I have repaired three optical units so far with this failure. The original winding was insulated twisted pair wound directly onto the Aluminum oven cylinder. I used teflon insulated heater wire, Pelican P2332ADVFEP.009BL. It is approx. 5 Ohms/ft. and I use a 50 Ohm length doubled and then twisted tightly. This is then wound onto the oven cylinder which is first covered with a single layer of kapton tape. The original thermistor is replaced with a DigiKey 615-1007-ND. The thermistor MUST be surrounded by heat sink compound. I also install a digiKey TO220 100 degree thermal cutout switch for future protection. It is mounted to the top of the lamp assy. using one of the 3 original mounting screws. The thermistor and heater wires are brought out tie wrapped along the original cable and then soldered to the appropriate pins on the db9 connector. Cheers, Corby ___ 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] Source of Rubidium Lamp for Efratom FRK
Hi Mike, That bulb was sealed with an oxy-fuel torch at the melting point of the glass. It was then annealed, starting at a much higher temperature than 150C before cooled slowly to avoid breaking. Heat it uniformly with your hot air gun until it is no longer black. Reducethe heat slowly to allow it to cool... or, you can toss it into a can full of white ashes from your fireplace. Or, leave it be and wait until it really fails before fixing it. -Chuck Harris Mike Niven wrote: Thanks Bob and Chuck for the comments. As Bob says, the lamp is easily replaceable (just unscrews) and the service manual gives the procedure. Maybe I'm too worried about how long the lamp is likely to last but the lamp voltage was below the range stated in both the Efratom and Racal manuals. The lamp itself certainly works but is a bit blackened. I had hoped that Corby's procedure for rejuvenating lamps might do more than it did for this particular lamp - maybe I chickened out too early in the heating process, but I was monitoring the local temperature with a thermocouple at over 150C consistently. Anyway, I have asked Sematron in the UK whether a replacement lamp can still be had. If it is available at $300-500, it is really not economic as the whole Racal 9475 cost a lot less. Mind you, I did put in a fair amount of work repairing both the Racal main unit and the FRK to get the system working. So, probably the best way of getting a spare lamp is to try and pick up another whole FRK and hope that its lamp still has some life in it. Anybody know whether the same lamp was fitted to other Efratom Rb sources? This would widen the search somewhat. Mike ___ 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] Just When You Thought It Was Safe ....
It is a common fishing technique, and the guy has done this several times over the last year, or so. When his sales dry up, he drops the price to $100, and then waits for a sale I'm pretty sure that he monitors this group for news of the new low price to leak out... and then quickly he bops the price back up to $150. I considered buying one about two such casts ago, and missed the low price point... and then decided that I didn't really need to play this game with the seller. -Chuck Harris paul swed wrote: Bob Just took a look and the pair seems to still be at $150. Maybe it was a special? The ovens are as you say $25 each and shipping for either 1 or 2 is $18.75. Regards Paul WB8TSL On Mon, Jul 27, 2015 at 8:44 PM, Bob Camp kb...@n1k.org wrote: Hi For all of you who dropped off the list back around Christmas and decided to re-join now that the KS box yack has died down ….. The usual auction site now has the pair selling for $100 and the “no GPS inside” part of the pair selling for $25 or two for $50. Mighty fair prices considering that they are new old stock rather than salvage units. (Yes I suppose that if we all hold off, they could go lower still. They also could head over for scrap metal reclamation) Bob (no connection to seller) ___ 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] Source of Rubidium Lamp for Efratom FRK
Hi Mike, The Rb lamp voltage is just a guide. If your Rb isn't working, then it is important... If it is, it is just a guide. If your bulb is clear, and it is glowing, it is probably also working. I seem to recall from HP's descriptions of how their 5065 was made that the lamp, and filter cell are a specially matched set. Just any lamp is not necessarily going to work with any filter cell. -Chuck Harris Mike Niven wrote: Thanks for the comment Bob. Tracing Efratom through the ages, I see they are now Microsemi. I wonder whether they will still have a lamp for such a geriatric Rb source and at what price - probably more than the cost of the complete Racal 9475? I will follow it up anyway as I hardly ever see working or scrap FRKs for sale in the UK. On Tue, 28/7/15, Bob Camp wrote: Hi The Efratom bulbs have a “magic mix” of gas in them. The only place I have ever bought them is direct from Efratom. They were fairly expensive back in the early 90’s … Bob On Jul 28, 2015, at 9:56 AM, Mike Niven mfniven at ymail.com wrote: Would anyone know of a source of the Rubidium bulb fitted in the Efratom FRK (and probably other FRx) standards? I have repaired and refurbished my Racal 9475, which is fitted with the older style FRK (not -H or -L) module. It is working properly at present but the lamp voltage is down to 5.5V, which is below the stated minimum of 6V. I have tried rejuvenating the bulb using a hot air gun, as described by Corby, but this has had no obvious impact. Hence, I have little feel for how much life the existing lamp has left and a spare would be good for my peace of mind. Many thanks. Mike ___ ___ 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] OCXO with ADEV of 1E-13 on Pluto Mission
I'm not sure what happened to all of the spares, but I do know that the spare bird was assembled, coddled, polished, and hung from the ceiling of the Udvar Hazy Air and Space Museum in Chantilly, Virginia. I think everything is there except for the RPG, and Tombaugh's ashes. I'm pretty sure it even has a copy of the disk that has all of our names stored in it. My wife designed some of the ASICs used in New Horizons. -Chuck Harris John Laur wrote: The link below is an updated version of the same paper: http://www.boulder.swri.edu/~tcase/NH%20RF%20Telecom%20Sys%20ID1369%20FINAL_Deboy.pdf It has considerably more detail on the RF components as well as the USO module for which there is an entire page of additional information and a block diagram. Whatever happened to the spare components probably happened a decade ago at any rate. Not that they wouldn't eventually wind their way to ebay anyway! Regards, John K5IT ___ 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] Omega counters and Parabolic Variance (PVAR)
Hi Magnus, Am I understanding correctly that the difference between Pi, Delta, and Omega is basically one of software processing after the sample is made? If so, how can this be best leveraged by those of us that have 5370A/B counters that are running John Seamon's enhanced BBB processor in place of the original 5370 Motorola processor? Thanks! -Chuck Harris Magnus Danielson wrote: Fellow time-nuts, Since I haven't seen any reports on this, I though I would write down a few lines. While normal counters use a pair of phase-samples to estimate the frequency, now called Pi counters (big pi, which has the shape of the weighing function of frequency samples), counter vendors have been figuring out how to improve the precision of the frequency estimation for the given observation time. One approach is to overlay multiple measurements in blocks, which for the frequency estimation looks like a triangle-shape weighing, so this type of counter is referred to as Delta counters (again to resemble the shape). Classical counters of the Pi shape is HP5370A, SR620 etc. Classical counter of the Delta shape is the HP53132A. However, counters using the Linear Regression methodology does not fit into either of those categories. Enrico Rubiola derived the parabolic shape of the weighing function (which I then independently verified after we spoke during EFTF 2014), and he then passed on the results to Francois Vernotte and other colleagues to continue the analysis. ___ 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] Omega counters and Parabolic Variance (PVAR)
Hi Magnus, John, et al, did such a nice job of making us a hammer for our 5370's, that it has the rest of us searching for nails. Maybe this could be a good place to start? -Chuck Harris Magnus Danielson wrote: Hi Chuck, On 07/14/2015 07:46 PM, Chuck Harris wrote: Hi Magnus, Am I understanding correctly that the difference between Pi, Delta, and Omega is basically one of software processing after the sample is made? Correct! If so, how can this be best leveraged by those of us that have 5370A/B counters that are running John Seamon's enhanced BBB processor in place of the original 5370 Motorola processor? I would stream the raw samples over to the computer and do processing there. Doing the Delta/Lambda estimation works if the computer side does the right post-processing (which they rarely do). Implementing this for frequency only in the BBB would not be too hard if you like to do that. I need to install my BBB board one of these days. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Leap second results: Ball/Efratom MGPS
I really thought I could be for once in my life be in with the in-crowd... I had my little Canon Mini-DV camera setup facing my Ball/Efratom MGPS display. The picture was clear, the focus was good... And 5 minutes before the appointed time, I started recording, and got a very good recording of the leap second...Yea! Wanting to be in, with the in-crowd, I immediately took my prize to my office, and I plugged my firewire cable into my camera, and went searching around the back of my PC for the firewire socket and drat! It didn't have one! I pulled the firewire card out of my old PC, and plugged it into my new PC, and . double drat! It crashed the PC hard, it wouldn't even boot the BIOS... I thought these things were supposed to be standardized... They are made in China, after all. I tried the firewire connector on my laptop, and again ... Drat! Drat! Drat! It doesn't even seem my camera. Finally, I picked up a couple of new firewire cards from my not so local recycler, and plugged them into my PC, and was able to download the recording of the leap second into my PC, and make a screen capture of the blessed (cursed?) event. It is displayed herewith. Moral of the story is, if you want to be in with the in-crowd, and you are just a mere mortal (like me), you had better rehearse *all* of the steps in advance. A happy Independence Day to everyone in the USA! -Chuck Harris ___ 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] Casio Watches 13 Year Drift in Seattle
Hi Andy, I think you would be guessing wrongly. The vast majority of watch owners don't want to ever have to set, wind, adjust the calendar, or in anyway think, or fiddle with their watch's time. They want it to just be right. In other words, their disinterest makes them the anti-time-nut. The engineering team that designed the watch is where the concerns about the watch always being right get turned into hardware. It costs them only a few days of an engineer's time to put, a temperature sensor, battery voltage sensor, and a table describing the nominal performance of the crystal at a normal range of temperatures and voltages, into the watch. It costs nothing on a per watch basis, as it is a trivial amount of additional silicon... silicon that resides within the necessary spaces between the pads used to connect the silicon die to the circuit board. As to per unit testing, the only testing required (after the initial design phase) is to program an offset into the watch that makes up for minor frequency variations in the crystal at nominal room temperature. Crystal manufacture is an imperfect process, so they have to do that anyway. -Chuck Harris Andy wrote: If this was normal back at the turn of the 20th century, why wouldn't Casio, and others at least do as well? Especially now that all electronic watches have a microprocessor built in... complete with temperature sensing diodes, battery monitors, and other nifty gadgets. I am guessing the vast majority of Casio owners don't especially care if their watch gains or loses a minute every month. So why bother to add sensors and circuitry to compensate for its environment? Furthermore, it requires setting the initial frequency on each watch built, to compensate for the crystal's initial error. And that jacks up the cost, perhaps more than adding those sensors would. Better to just churn them out with as little per-unit testing as possible. That's just my guess ... but who am I to say? Regards, Andy ___ 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] Casio Watches 13 Year Drift in Seattle
Back in the day when mechanical escapement pocket watches, and wrist watches were state of the art, the jeweler would adjust the watch to run at a normal rate, and give them a daily wind. Everything looked nice in the display case. When a customer bought a watch, the jeweler would set the watch to his shop clock, and instruct the customer to wear, and wind the watch normally for two weeks, but do not set it. At the end of the two weeks, bring the watch back to the shop for a check up... When the watch came back, the jeweler would calculate the number of days the watch had been worn, note the difference from his shop clock, and calculate the daily rate of the watch. He would then set his timing machine for the the inverse of that rate, and set the watch to match. Now, when the customer wore his watch, the watch would seem to always be right on because it was adjusted for a rate that compensated for the customer's patterns of wearing the watch...his personal error. This trick had an added advantage because the customer got to see how so-so his brand new watch behaved during those two weeks, and got to be dazzled by his jeweler's rare ability to make the new watch perform so much better than the factory could! If this was normal back at the turn of the 20th century, why wouldn't Casio, and others at least do as well? Especially now that all electronic watches have a microprocessor built in... complete with temperature sensing diodes, battery monitors, and other nifty gadgets. -Chuck Harris Bryan _ wrote: But wouldn't normal watch wear just balance itself over time, one wears their watch for say 12 hours and the rest it sits on a counter at a much colder temperature. So wonder if Casio would actually go to such lengths to compensate. Maybe, interesting though. -=Bryan=- ___ 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] Testing the Datum LPRO Rb oscillator
Generally, rubidiums do quite well when left powered down. They don't use the extremely hard vacuums characteristic of cesium standards. Other than the usual electronic component failures, the only thing that usually happens to cause a rubidium to stop working is the lamp gets blackened by rubidium condensing out on the glass in a the beam path. This causes the signal strength to drop to a point where the servo can no longer lock. The usual cure is to heat the bulb carefully until the rubidium is once again all vaporized, and let it cool I use a hot air gun to supply the heat... Once the bulb is cleared, you are good to go for another lifetime. -Chuck Harris Sean Gallagher wrote: Good afternoon everyone, So I have a bunch of Datum and Efratom LPRO Rb oscillators. I know that one of them is bad and I already swapped it out. I was getting really long lock times (if lock at all happened) and read that was an indicator. These things were all made from like 1999-2001 or so and from what I understand have about a 15 year lifespan. However a former colleague told me today that this limitation is really only if they are powered on. Is this true? If so then some of these units apparently were only hooked up for a couple years and then the servers they were in were taken offline and they may still have 10+ years of service right? I was really wondering if someone could point me in the right direction (or towards a tutorial) on how I can test these and see if they are still okay? I don't have a lot of engineering experience but I do have access to a multi-meter and an oscilloscope and a decent amount of luck when it comes to troubleshooting. Respectfully, Sean Gallagher Malware Analyst 571-340-3475 ___ 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] KS-24361 NO GPS - again
Thees units were made for the phone company, and phone companies are big on hot-swapping modules. The shorter pins are shortened to make sure that their circuit doesn't make contact until the longer pins have made contact. Don't fix them! -Chuck Harris billriches wrote: Hi Ulli, I heard some comments that the short jumper cable between the two units would make an intermittent connection. You will notice that some of the pins in the connector are shorter than the others and hopefully that is the problem. I don't know if the plugs are wired 1 to 1, 2 to 2 and so forth but you could figure that out and make up another cable and try it. Hopefully your problem will be as simple as a bad cable. I have had two of those systems running 24/7 for almost a year and have had no problems. 73, Bill, WA2DVU Cape May ___ 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] 3048A software question
The easiest way of getting a new well supported version of DOS, is to download FreeDOS. Anything that worked on any version of MSDOS will run under FreeDOS... and so much more! -Chuck Harris davidh wrote: Folks, I'm also working on getting the MSDOS version running. What is the most recent version of DOS that people have found to work with the A 01.01 version. Also, can anyone advise where the command drivers for the 82335 can be found? Cheers, 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.
Re: [time-nuts] Terrestrial Tides and Land Movement
Hi Bob S, An HOA can be a daunting problem, but not one that cannot be solved with a little guile. Every house I have ever seen that has modern plumbing has a few vent stacks on the roof. Would the HOA even notice if yours sprouted another one dark weekend evening? All the kit you need to add one to your roof is available at your local big box store. The usual bullet style antenna, sitting on top of a PVC vent pipe would be invisible on most houses, particularly if it were to be placed in the same vicinity as the rest. Also, GPS bullet antennas are pretty well sealed, save for the connector on the bottom. If you do a good job of sealing the connector (eg. lots of wraps of electrical tape, followed by a few of friction tape) there in no intrinsic reason you couldn't safely mount yours on top of the main plumbing vent stack. Drill a hole in the side at some convenient spot inside of the house, and snake the coax up through the vent stack, mount the antenna over the top, leaving adequate vent space. (OBTW, it isn't a vent stack until it is above the highest fixture in the house.) Although I don't have an HOA on my farm, I have my antenna mounted that way on my radon mitigation pipe. I bent up a couple of pieces of aluminum to make an open plug and put the antenna up without ever setting foot on my roof. I simply snaked the cable up and out the top of the radon pipe, and when I could reach it from a window, installed the GPS antenna, and aluminum plug, and then pulled the antenna cable back through the pipe, causing the plug and antenna to pop into the pipe mounting the antenna. -Chuck Harris Bob Stewart wrote: Hi Bob, Thanks for taking the time to explain the 4ns and 20ns wanders. I have just been calling them constellation errors without being able to explain it better than that. I've also wondered how much of the 20ns, if any, is attributable to the PRS-45A. I still don't have the antenna located in a position suitable for precision timing. The power of the HOA is not to be trifled with. That, and the sky is full of power lines and other junk around here. Bob ___ 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] TimeLab and Wine: was Re: New 5370A
Hi Bob, I just got back from my son's commencement ceremony, and finally have a little time to maybe give a few pointers. First, safety prevents one from trying to run too many different applications within a given wine sandbox (aka bottle). It is best to give each application its own sandbox, and let it run on its own... the same is true sometimes with windows... the cause of most problems in windows is odd combinations of DLL's provided by odd combinations of applications. Second, if you see a completely messed up screen, it is very likely due to using a non windows compatible font in wine. It is best to use the real msoft true type fonts... for whatever reason (most likely poor documentation), the clone true type fonts aren't very good clones. Third, running multiple virtual windows devices on the same linux machine is simply asking for trouble. You wouldn't consider running multiple copies of XP under XP, why would it seem ok to run multiple XP virtualizations under linux? Each of the virtualizations uses hooks into kernel routines, and it is likely that they get in each other's way. I have found timelab to work ok under wine, in its own sandbox, with no other virtualizations running. For what it is worth, IMHO, the best version of wine is the one sold under the name CrossOver, by CodeWeavers. They are using a plain version of wine, with some packaging to make the different applications work better. They also have a package of scripts to configure wine for a great number of different packages. The scripts pull in any needed windows DLL's, and applications. It's cheap to buy a years support, and they give all of their enhancements back to the wine project. -Chuck Harris Bob Stewart wrote: Hi Chuck, I've renamed this thread, and expect it to die quickly. I have a bunch of things running on my Linux system, so I see a lot of interactions that probably don't happen to others. One thing is that Timelab doesn't like to come up properly under Wine. For some reason, it mostly comes up with the chart/plot covering the whole frame, rather than having the legends at the bottom and at the right. The biggest impact to me is that it doesn't play well with MPLABX. But, I've seen other problems related to MPLABX, so suspect that the problem lies there. Finally, I've noticed some interaction between Timelab and VirtualBox. I was running a Windows XP client, and the client got destroyed. That's never happened before. OTOH, I was trying to use a clone 82357B from the boxed client, so that may have somehow bled into Timelab. I dunno. Of course, it could have just been a random failure that appears to correlate with Timelab. Note that I'm not shaking a finger at John. Wine is essentially the wild west at times, and this is one of those times. Bob ___ 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] New 5370A
Bob Stewart wrote: ... And kudos to John for Timelab. It doesn't play well with Wine in Linux, but that's not terribly surprising, all things considered. Really? How so? Wine tends to be a bit more pedantic than windows itself, but most things, that don't go out of their way to break Wine, seem to work... even a few viruses. When I tried timelab, on Wine, it seemed to work ok for me. Lady Heather also works nicely on Wine. -Chuck Harris ___ 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] lawnmower robots may be the end of VLF timekeeping
Bill Hawkins wrote: Did the pictures have to be in SVG format? SVG is extremely available, and extremely useful because it allows you to scale the picture to any size you like, and retain all of the detail. It provides a lot more functionality than just that, but I am sure that you can use google to discover what that might be as well as most anyone. To quote the wiki entry for Scalable Vector Graphics: All major modern web browsers—including Mozilla Firefox, Internet Explorer, Google Chrome, Opera, and Safari—have at least some degree of SVG rendering support. My Mozilla based browser came with full support out of the box, so to speak. I expect that whatever browser you are using either natively supports SVG, or can pull in a plugin. If not, prudence dictates that it might be time for an upgrade... if only to gain the benefit of the latest security patches. Is this only a problem for those who routinely use SVG? Maybe. I expect that the solver of this problem will be someone who is flexible enough to embrace a wide variety of new techniques, and processes. -Chuck Harris -Original Message- From: Poul-Henning Kamp Sent: Saturday, May 09, 2015 7:16 AM I spent some time capturing some data today. The measurements is from my $20 loop-antenna in the attic, which is something like 8 meters up and 10 meters besides the lawn-mower loop: http://phk.freebsd.dk/time/20150509.html ___ 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] EMI and CE certification
Yes, but in the case of the lawnmower fence, and the invisible dog fence, the transmitter drives the fence as an antenna. In the US, the antenna size for free bands is seriously limited. As an example, the so called Lowfer band at 136KHz is limited to antennas no larger than 15m in length. And, that is one of the larger limitations. 15m would encircle only a very small lawn. OBTW, I realized on reading my post below, that I was very unclear on what could be foiled. I meant that the operating permission for the lawnmower system could probably be foiled by looking into the maximum antenna lengths for unlicensed services of this sort, in this frequency range. I would quite imagine that any certification they may have is for the transmitter and receiver, without an antenna. -Chuck Harris Alex Pummer wrote: yes for transmitter antennas, but not for receiver antennas in Austria Germany Switzerland France Hungary one could have receiver antenna as long as he want, but the height is limited similarly as in the US 73 KJ6UHN Alex On 5/10/2015 7:15 AM, Chuck Harris wrote: My recollection is that in the US, certain requirements exist for antenna length on the so called free bands. I have no idea what the European requirements might be, but, perhaps they can be foiled by their allowing their minuscule amounts of power to flow into an over length antenna? -Chuck Harris ___ 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] EMI and CE certification
My recollection is that in the US, certain requirements exist for antenna length on the so called free bands. I have no idea what the European requirements might be, but, perhaps they can be foiled by their allowing their minuscule amounts of power to flow into an over length antenna? -Chuck Harris Magnus Danielson wrote: ... Depends. If they use approved frequencies and powerlevels it may be fine. In this case it doesn't look like it. There are telemetry frequencies allocated, they should use those. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Important parameters for a GPS/GNSS antenna
Probably about the only accurate way, really. A GPS antenna is light weight enough that it could be mounted to a suitable turntable clamped to the shaft of a stepper motor. The assumed physical center of the antenna could be mounted directly on the axis of rotation. Then you would know accurately the angle of rotation. If you plotted the GPS location relative to the angular rotation, you could then know the offset from the assumed physical center, and the real phase center... -Chuck Harris Poul-Henning Kamp wrote: In message fc02a5e8-5396-4474-a307-546e10909...@n1k.org, Bob Camp writes: The “put the antenna up and rotate it to see what happens” experiment has indeed been done. The objective was not correcting the antenna’s issues, but validating that their model of the antenna’s phase center was correct. They were trying to see if anechoic chamber data really gave correct answers in free space. So this could be a realistic way for us to calibrate the phase-center of an antenna ? ___ 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] TymServe 2100 1995 Issue - A Kludgy Fix
Seems to me that the obvious simple answer works this way: Since the GPS must use an RS232 connection to communicate its information to the other devices in the telescope, all that need be done is to write a fairly trivial program to run on a PIC, or Arduino, that when presented with the date, adds 20 to the year, and then sends it on to the rest of the system. Everything that is not a date gets passed through unmolested. -Chuck Harris Pete Stephenson wrote: On Tue, May 5, 2015 at 2:42 AM, Andrew Cooper acoo...@keck.hawaii.edu wrote: We also ran into the TS2100 1995 bug this weekend. For us the consequences are a bit more severe... The telescopes will not point to the right location in the sky without accurate time! Ouch. I have some friends who work at the Subaru telescope. I'll check in to see if they're affected. For now we have configured a temporary fix... We set up two units, previously our primary and hot spare. The first unit is set to use GPS, which of course has the correct time but the wrong date. The first unit is sending a 1PPS signal to a second unit which is set to 1PPS input mode with a manually set date and time. We now have all of the IRIG and NTP capability we need and the correct date. Out of curiosity, is there no way to prime the device with the current date/time (e.g. from a wristwatch) so it can interpret the GPS week information correctly? I recall that several other devices have that ability. Is there a list of other common time-nut devices that are susceptible to similar issues? Lots of time-nuts use surplus equipment that's no longer supported and it'd not be fun to have them stop working. Cheers! -Pete ___ 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] TymServe 2100 1995 Issue - A Kludgy Fix
Hi Tom, One of the first words I taught my precocious kid when he was less than a year old was balderdash. It seemed appropriate for him to know that word if I was going to be his father. Hard for me to believe that little boy graduates from CMU with his BS in physics this month The currently buggy GPS receiver is outputting UTC time that is offset by 1024 weeks, and some number of seconds from reality. The past is irrelevant if we know the present offset. Add in that offset, reformat the UTC data frame and send it out when asked. An Arduino can do that in a very small number of milliseconds. And, the Arduino's time burden can be well known and applied to the data, if it is significant. Surely the receiver is still producing correct frames that identify the future leapsecond, and those frames could be read, and used to set a little routine that wakes up at the appropriate second, and adjusts the overall offset? Seems way simpler to me than all of that code I had to wade through and cleanse of Y2K bugs. Since the OP was talking about a multi million dollar research telescope, which presumably matters to a lot of people, I will refrain from commenting about the wisdom of ignoring the well publicized 1024 week roll over bug, and not replacing/reflashing the GPS receiver years ago. -Chuck Harris Tom Van Baak wrote: Hi Chuck, It's not that simple. First, it's not 20 years, but 1024 weeks (19.6 years). And not UTC weeks (which may have leap seconds) but GPS weeks (which do not, and are always 604800 seconds long). So you have to convert the incorrect UTC date and time back to GPS date and time, then apply the 1024 GPS week correction, and then convert back to UTC. This requires knowledge of all leap seconds during the past 1024 week cycle and this information is not present in the GPS signal or in the binary or NMEA messages that come out of a GPS receiver. Don't forget to account for all the leap years during that period too: 1024 weeks is 19.638 normal years but 19.585 leap years. And when you power-on the GPS receiver it may have the wrong leap second count as well, wrong for both 1995 and wrong for 2015. You have to wait up to 12.5 minutes for that information to come down at 50 baud. Not saying it isn't possible, but it's not easy. And then you need to test it against last week and this week, and the week before and after June 30 of this year when the next leap second occurs. I realize the TymServe 2100 issue is unrelated to leap seconds. But leap seconds severely complicate any simple conversion between time scales, especially if you are interested in second or sub-second accuracy. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Visual clock comparison
Yes, I meant 18000 BPH. My fingers have a mind of their own and type things that I don't always want. I apologize for my many and varied imperfections. I never said that 18000BPH was the only rate used... only that standard stopwatch ticks are 18000BPH. An Elgin Jitterbug is anything but a standard stopwatch. A variant of the Elgin was used with the Norden Bomb sight... Probably the only mechanical stopwatch in history to be classified as top secret by the US Govt.. (If your Elgin was last serviced more than a year ago, I would venture that it no longer runs at 40BPS.) 18000BPH was the standard beat for pocket watches and wrist watches when stopwatches were invented. 18000BPH is where any reference to 5 beats per second comes from. 18000BPH is where the 0.2 second limit on conventional stop watches comes from. And, 18000BPH is what you will get if you buy a normal mechanical stopwatch... Which, oddly enough, you can still buy. -Chuck Harris Bill Beam wrote: On Sun, 19 Apr 2015 23:25:10 -0400, Chuck Harris wrote: 1/5th second is simply the rate at which the balance wheel on a standard stopwatch ticks... 18000BPM. -Chuck Harris You must mean 18000BPH. There are many balance wheel rates in use from 4.5BPS to 10BPS and higher. My Elgin jitterbug stopwatch runs at 40BPS. Bill Beam NL7F ___ 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] Visual clock comparison
1/5th second is simply the rate at which the balance wheel on a standard stopwatch ticks... 18000BPM. -Chuck Harris Jim Lux wrote: Hence the reason that horse races are traditionally timed in 1/5th second increments. (1/5th second is also about 1 stride for a race horse at full gallop 3.5-4 m/stride... 17 m/s) a bit of googling turns up https://books.google.com/books?id=PlQkH-OxxucClpg=PT489ots=l0HxdHUOJpdq=horse%20race%20timing%20stopwatch%20historypg=PT489#v=onepageq=horse%20race%20timing%20stopwatch%20historyf=false Stopwatches timing to 1/5 second were being used to time races befor 1731, by which time they were in commercial production, seven years befor ethe earliest use of 'stop-watch' known to the OED ___ 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] KS-24361 Power Module Repair
I thought the context did a pretty good job of explaining it, but if it did not, I am sorry. Epoxy potting compound is a lot easier to remove than the silicone RTV based varieties... Although the silicone variety starts out soft, it is not crumbly. The epoxy sort loses its cohesiveness with its hardness when hot. If you stick a screwdriver into it, and twist, it pops off decent sized crumbs. What I typically do is take a dental probe that is dull, and slide it between the board and the potting compound, and strip off chunks of the potting material. Or I use small 1/8 inch blade screwdriver and do the same. It goes pretty fast... you avoid toroids, and things with fine wires, of course. The easiest way to remove silicone potting compounds is to take advantage of silicone rubber's voracious appetite for slurping up petroleum solvents. Put the item you want to strip in a container filled with naptha (aka lighter fluid, or fuel) and let it soak over night. By morning, there will be this highly bloated and fractured gelatinous mess all over the board. -Chuck Harris Bob Stewart wrote: OK, that explains your comment. This is most likely a silicone based potting compound. It's a bit softer than an eraser when cold. Very little of it was actually stuck to the board or components. If it had been a hard, epoxy-based covering, I wouldn't have bothered with it. Bob ___ 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] KS-24361 Power Module Repair
No, I meant exactly what I said. When you are removing epoxy potting compound, put it in an oven set to 140C, and let it cook until up to temperature. The potting epoxy will become about as soft as pencil eraser rubber. You can then pick at it, and get pretty big chunks to come off. When the epoxy starts to feel hard again, pop it back in the oven. -Chuck Harris OBTW, we are not talking about crystal ovens here, but rather unpotting power supply modules. Al Wolfe wrote: This seems a bit toasty and is equivalent to 284F. Maybe meant 140F not C? An oven set to 140C is your friend when doing jobs like this. FWIW, the GE Progress Line two-way radios oscillator crystal holders had an octal base, held two crystals, and the heating element could be used on 6 volts or 12 volts depending on which way the holder was plugged in. I have no idea of how well they held the temperature. Always planned to use one with an external proportional controller but never got around to it. Al, k9si ___ 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] KS-24361 Power Module Repair
That is almost a carbon copy description of how I fixed a similar module in my Ball/Efratom MGPS unit on my GPSRb unit. An oven set to 140C is your friend when doing jobs like this. The guys that make these modules are trying to make them as small as possible, so they always use tantalum capacitors, and run them very close to their ratings... in this case, it was 18V on a 20V cap. This particular module had +/- 15V, and +5V on board. I have never seen so many individual switching power supplies stuffed into a single module... They were all little 5 terminal IC's, with each running at whatever frequency it felt like... -Chuck Harris Bob Stewart wrote: This is just a brief report, not a how-to. I got a KS_24361 with a bad Lucent power module. Having nothing to lose I thought I'd see if it came apart. After unsoldering it from the motherboard, I found the usual potting compound. Fortunately, the compound was only loosely attached to the board in the brick and was easy to pick off. After that, I used a pair of needle-nose pliers to work the board out of the casing. In spite of the pic below, I first gently pried up on the corners, in succession, until the corners released. Then I worked my way toward the middle, until the board came out. Be aware that there are two small inductors on the top side of the board that have metal covers that will probably stay in the potting compound. Just leave them there. When you push it all back together the covers will go back on the inductors. http://evoria.net/AE6RV/KS/OpenUp.jpg One corner of the brick was pretty hot while I had it on, so I figured there was a shorted component. As it turned out, it was a 15uF tantalum cap with a big brown spot on it. http://evoria.net/AE6RV/KS/BadCap.jpg Here's the cap removed from the board at the upper left. http://evoria.net/AE6RV/KS/CapRemoved.jpg So, ordered the cap, put it on the board, then just pushed the pins into the motherboard for testing. I didn't even bother soldering it. http://evoria.net/AE6RV/KS/Testing.jpg Tests were good, so I stuffed the board back into the casing, and soldered it all back on the motherboard. I didn't bother repotting the bottom surface of the board. I attached the repaired KS to my good REF-0, and it's now working. Bob - AE6RV ___ 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] 58503A alarm light on, but :SYSTEM:STATUS? indicates all is ok
I can't help but notice that you have several of these entries: Log 067:20150101.00:00:11: 5V is out of tolerance, value: 5.52 Log 068:20150101.00:00:11: 15V is out of tolerance, value: 19.46 I think you better look into them before anything else. -Chuck Harris Dr. David Kirkby (Kirkby Microwave Ltd) wrote: Yesterday (31st March 2015) the GPS lock light of my 58503A went out and the Holdover light came on. The Alarm LED was *not* on. It had been like this for an hour or more. I removed the N connector, could see there was 5V DC on the antenna, and a visual inspection of the antenna cable did not give me any cause for concerns. I decided to power cycle it. Anyway, it came back up, quickly achieved lock, and I'd rather hoped it was just a glitch, and that was the end of it. NO SUCH LUCK! Today I notice the GPS lock light is on, Holdover is off, but the alarm LED is on. This is quite a different set of LEDs to yesterday. This time I connected the GPS receiver to a computer, to try to find out what was up, and are confused in that the status appears to be ok, yet the alarm is on. The log does not indicate why the alarm light should be on. (I have had it come on before, immediately after power up, when it indicated the power supplies were out of regulation, although I've never managed to observe this on a peak holding DVM, so I am not convinced the power supply was the cause.) But the unit has been stable for quite a while, yet the alarm is on, but nothing in the log indicates a problem. ___ 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] Need advice for multilateration setup
The biggest problem I see is the crystal oscillator in the rocket is going to notice the G forces during acceleration in a pretty big way. Time nuts easily notice the reversal in a 1G force on a laboratory oscillator caused by flipping it on its back for service. But all is not even close to lost. If your transmitter is amplitude modulated with a rate that is a digital division of your crystal's frequency, then you can remove any G-variation in the crystal's frequency by observing frequency variations in your modulation. Doppler will change the carrier frequency with speed, but it won't change the amplitude modulation frequency. Otherwise it should work beautifully. -Chuck Harris Peter Reilley wrote: Robert; It seems that a Doppler system should work for you. But first, you have a problem. If you want to track your rocket to 100K feet (20 miles) using some form of triangulation then you need your receiving stations further apart than 1 mile. Your triangle is too extreme and any measurement error will be greatly amplified. Here is what I suggest. ___ 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] Comparing the BeagleBone Black Raspberry Pi as NTP servers
One of those services is likely the full blown web server that runs on the BBB to allow you to view the help pages. -Chuck Harris Attila Kinali wrote: On Sat, 21 Mar 2015 16:23:30 - David J Taylor david-tay...@blueyonder.co.uk wrote: I've just put up my first draft of a comparison of these two popular devices as NTP servers: http://www.satsignal.eu/ntp/BBB-vs-RPi.html Comments welcomed - I know it's an imperfect test! Something is wrong here. I would expect the BBB to perform at least as well as the rpi (after all, the BBB has an ethernet MAC with IEEE1588 support, while the rpi is basically a glorified USB controller with attached graphics card). You are most likely running services on the BBB (network services, local services, cron jobs,...) that cause the high, and spikey cpu load, which in turn destroys your ntp performance. Also, compare your results to [1], where Dan Drown uses the capture/compare unit of the AM3359 to timestamp the PPS and use this for ntp. In [2] he tries to measure the temperature dependence of the BBB oscillator (not be best way, but...). Attila Kinali [1] http://blog.dan.drown.org/beaglebone-black-timer-capture-driver/ [2] http://blog.dan.drown.org/tcxo-beaglebone-black/ ___ 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] Lady Heather
I Do. She works with wine on linux, and likes it! -Chuck Harris Dave Mallery wrote: hi does anyone have the lady running on WINE under Linux?? On Wed, Mar 11, 2015 at 6:13 PM, Paul Berger phb@gmail.com wrote: I have also used LH with a Thunderbolt 'E' and did not have any issues, however I have not turned on the E for some time now. Paul ___ 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] PRS-1- Rubidium
All epoxy dipped tantalum capacitors are dry electrolytic tantalum capacitors. Dry electrolytic tantalum capacitors have no electrolyte. That is why they are called dry. In manufacture, a sintered tantalum slug is etched so that its surface is full of lots of nooks and crannies. A microscopically thin solid dielectric coating is applied to the slug, and then a coating of a conductive metal is applied over the dielectric. The slug is one electrode, and the conductive metal coating is the other electrode, and the dry dielectric coating is the dielectric. There is nothing in a dry electrolytic tantalum capacitor to cause corrosion. However, burned epoxy circuit board is very corrosive. -Chuck Harris Bruce Hunter via time-nuts wrote: Jurg, I did not see your picture before responding earlier. Check the dipped tantalum on the right for a hole that spouted acid. The device on pillars is a preliminary heating resistor for the rubidium bulb. Be sure to measure its spacing from the bulb, if you are going to remove the circuit board, as this is critical to the warm up cycle. Bruce, KG6OJI ___ 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] XOR frequency doubler question 5/10 Mhz
Hi Paul, It isn't that it is bad, it is just that 5 and 15MHz products at 8 to 10dB down isn't very encouraging. To make decent use of this technique, I believe that you would have to install 20 to 30dB of 5MHz rejection, and a 10MHz low pass filter in the output circuitry And, that is in addition to making a simple very stable 90 degree phase shifter. The 5MHz rejection filter is necessary to prevent phase anomalies from appearing due to the beating of the doubled 5MHz fundamental with the XOR gate created 10MHz signal. Any time you add filters, you are adding temperature dependent phase shifters to your circuit. -Chuck Harris paul swed wrote: Experimenting with a 74ls86 XOR doubler for 5 to 10 Mhz. Typically this would use a 90 degree phase shift to the other gate. The gate acting as a mixer to produce 10 Mhz. The reason to experiment is that I have noticed most of the doubler discussions take a 5 Mhz square wave filter it to a sine wave, feed it to a multiplier scheme and then filter the output. The 7486 method eliminates one of those processes. I have accurate delay lines I can adjust in 2 ns increments (Allen Aviation lump LC). The output is a semi asymmetrical square wave due to some gate timing I need to deal with if possible. Setting the delay taps to 90 degrees produces a 10 MHz output with 5 and 15 Mhz 8-10 db down. Lots of other higher frequency outputs. At this point I have no filtering on the output of the 7486. Purposely mis-adjusting the taps sets either the 5 Mhz or 15 Mhz level higher. Other noise and such are many DB down 50 plus. Why is this a bad method as compared to our typical time-nuts discussions? Regards Paul WB8TSL ___ 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.
