Re: [time-nuts] My Favorite Watch

My Timex Indiglo looses about a second a month. I think that's pretty good for a <$30 watch I got at Walmart. Al Virus-free. www.avast.com

Re: [time-nuts] TrueTime XL-AK Questions

Dick, I have had a couple of the XL-AK receivers here for several years. They both do not have the down converter option and do put out 5 volts to the antenna jack. It is simple to measure with a volt meter into the antenna jack. While they kind of worked with a hockey-puck antenna, they a

[time-nuts] Mystery Oscillator

Found an old oscillator when cleaning out a barn. It is a model YH890-1 made by Greenray Industries. Since it is 10 mhz. output, I though it might be useful for something. It has a BNC connector which I assume is the output and three terminals on the side. One is chassis ground. The label says both

Re: [time-nuts] Frequency counter questions

I am surprised that no one has mentioned the idea of heterodyning a known frequency with the unknown to measure the unknown. I use a Minicircuits doubly balanced mixer fed on one port from a PTS160 synthesizer that is locked to 10 mhz. from a TrueTime xl-ak GPS locked receiver. The second port is f

Re: [time-nuts] Line Frequency Stability

Back in the 1970's I was chief engineer at a couple of local radio stations. They were automated and needed to carry network programs at the top of the hour in real time. The switching gear used electrical motors with cams and roller switches. These motors were locked to the line frequency and

Re: [time-nuts] WTB: GPSDO

Jeff, I have been using a TrueTime XL-AK purchased on eBay a few years ago. It has worked flawlessly for the last five years. It seems to work well with most amplified antennas that I have tried. Supposedly accurate to better than 10 -12 but I have nothing to compare it to. It will supposedly c

Re: [time-nuts] Earthmate

It seems to me that the Earthmate wants to receive the string "ASTRAL" before it will send out anything. Haven't used one in fifteen years or more. Al, k9si ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-b

[time-nuts] Maser 0.7 nsec jumps solved

Maybe the simplest solution would be to try a rudimentary form of step-start relay to crank the A/C compressor. This used to be quite common before the days of VFD's and such. The regular start relay applies power to the motor via a resistor that limits inrush current to some safe level to start t

Re: [time-nuts] Trimble Thunderbolt E frequency pulling

Nigel, Set your counter to high impedance. Then install a T connector on the input. Then you can install or remove a 50 ohm terminator on the T while plotting the results. Then you can see how fast the frequency shift is depending on the load. AL, k9si Switching the impedance at the coun

Re: [time-nuts] modern electronics education/jobs

And don't wipe your soldering iron on your wash-and-wear fatigues as we used to do with the cotton ones. Al, k9si And I agree, don't solder in the nude or while wearing shorts, and don't walk barefoot in your workshop. ___ time-nuts mailing lis

Re: [time-nuts] looiking for rakable GPSDO

Stephane, I got a TrueTime Model XL-AK unit from ebay a couple of years ago and been quite happy with it It is rackable, has several 10 MHz. outputs, and just plays. Using a bullet antenna, also from ebay. Al, k9si Hello, I'm looking for a 10 MHz output GPSDO with external antenna which

Re: [time-nuts] Symmetricom / Truetime XL-AK

Jim, I have a Truetime XL-AK and have tried several 5 volt antennas with it including the little square magnetic ones. They all worked OK as long as they were outside. I did find a $30 imported bullet on ebay that I am using now. Since I installed the bullet last winter I have had no dropou

Re: [time-nuts] TrueTime AL-AK GPS receiver help

Does this AL-AK have a real GPS receiver in it? Does the unit have a board with a crystal of 16.368MHz. that is multiplied by 96 up to 1571.328, the mixing frequency to get to the GPS freq of 1575.42? Since the down convert-up convert is offered as an option perhaps TrueTime used an actu

Re: [time-nuts] KS-24361 Power Module Repair

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. ___ time-nuts mailing list

Re: [time-nuts] KS-24361 Power Module Repair

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

Re: [time-nuts] time-nuts Digest, Vol 127, Issue 33

I have an XL-DC and it has an internal GPS receiver in it. It supplies and monitors 5 volts to a BNC antenna jack for an external amplified GPS antenna. I don't know what the internal GPS engine is but doubt if it is anything special. The manual describes the down converter system as an

Re: [time-nuts] fast switching quiet synthesizer

Jim, This reminds me of a project I did back in the early1990's. (Hopefully we have advanced a bit since then.) It used a bunch of quad latches, some 74138's, a UART, and an RS232 converter. It drove a PTS 40. The UART used the first 4 bits for BCD frequency and the last four bits to address

Re: [time-nuts] GPS-III

On eBay the RNY25A1 receiver module sells for $15 and $1 for shipping from Taiwan. Supposedly, it does GPS and Glonass. There is a link to a data sheet there as well. Might be interesting to play with one and compare the results. Stick it in a Tupperware box and nail it to a fence post. Al,

[time-nuts] Diodes as temperature sensors

Back in the 1970's I was tasked with coming up with a thermometer that could be read in the studio of an AM radio station. I bought a Heathkit indoor-outdoor unit. It worked great at night but was all over the place in the daytime when the AM transmitter was on the air. Turned out the sensor wa

Re: [time-nuts] Interesting frequency standard project

As stated AM stations in US must maintain 20 Hz accuracy. Most are well within that tolerance. I have measured many AM station's frequency as a function of my employment before retirement. Now comes HD radio. While the merits of HD AM radio are very much open to debate, one benefit is th

Re: [time-nuts] FASTTRAX GPS

Back in the 1980's I was tasked with installing about 100 terminals (VT100 type) to a mainframe computer. These all ran at 9600 baud, RS232. Some of the terminals were almost 1000 feet wire distance from the switch. We used some Beldon multiple twisted pair to interconnect these devices with

Re: [time-nuts] Measuring the accurcy of a wrist watch

Tom, Thank you for your response. I don't think I could improve on the accuracy of this old watch much by trying to "regulate" it. I was more curious to see if there was any way to determine what was going on in side it with out actually opening it. The buttons on the side have long cea

Re: [time-nuts] Measuring the accurcy of a wrist watch

I have a Timex watch that's probably seven or eight years old. It has an LCD readout. The buttons haven't worked in years. It looses about one second every three or four months. I have to take out the four microscopic screws in the back to get into it to set it. The only reason I hang onto it

Re: [time-nuts] fast edge, rise time.

Years ago I had a cousin who ran a civilian calibration lab. For calibrating scopes, etc, for rise time he used a mercury wetted relay which he claimed had nearly instant rise time and no bounce. Seems that he used a resistive divider and the mercury relay shunted a portion of the divider. With

Re: [time-nuts] HP 4193A 4815A probe compatibility

There are many detector chip out there. The venerable AD8307 with greater than 80 db dynamic range goes from almost DC to 700 mhz. Linear Technology has several currently listed. Their LTC5508 covers 300 to greater than 7 GHz. Al On Oct 17, 2013, at 3:38 PM, Richard Karlquist wrote: If

Re: [time-nuts] GPSDO choices

been quite happy with it but then, maybe I don't know any better. Al Wolfe I'm looking for a new, ready to go, inexpensive" desktop GPSDO. So far I've only found the Fury and Thunderbolt E. Are there other reasonable choices e.g. the J R Miller (although I'm not sure t

Re: [time-nuts] FE-5680A Loop Lock Indicator

I'm surprised no one suggested using two 2N's in Darlington. Then a 22K or more from the base to the indicator pin would not load things down much. Collector load then 1.2K to 2k in series with the LED. Al, K9SI ___ time-nuts mailing list --

Re: [time-nuts] 9390-55108 IRIG

The TrueTime GPS receiver and frequency standard I have puts out IRIG-B as well as 4 each 10 Mhz. signals. What in practical terms is the IRIG-B (AM, not DC) good for? Al, K9SI The DC code was usually TTL compatible PWM and the IRIG-B would be 3V pk-pk AM. Marker 8 cycles, "1" 5 cycles an

Re: [time-nuts] NTP Clock suggestions?

I actually built a contraption like this back in the 1970's. As chief engineer at a couple of automated radio stations, I was tasked with keeping the network-joiner clocks accurate. It sounded really sloppy to have dead air or to up-cut the network. These clocks were 60 htz synchronous motor

Re: [time-nuts] NTP Clock suggestions?

I actually built a contraption like this back in the 1970's. As chief engineer at a couple of automated radio stations, I was tasked with keeping the network-joiner clocks accurate. It sounded really sloppy to have dead air or to up-cut the network. These clocks were 60 htz synchronous motor

Re: [time-nuts] OXCO Issues -- Latest

Years ago we were taught that it was poor engineering practice to use pots to trim a DC value, especially if any appreciable current was to be drawn from the wiper. (Probably true for any kind of signal on a pot) It seems that current through the wiper would eventually erode away the material u

Re: [time-nuts] OXCO Issues -- Latest

Years ago we were taught that it was poor engineering practice to use pots to trim a DC value, especially if any appreciable current was to be drawn from the wiper. (Probably true for any kind of signal on a pot) It seems that current through the wiper would eventually erode away the material u

Re: [time-nuts] Measuring Phase diference between different GPSDO

How about just running the two different 10 mhz outputs into a doubly balanced mixer and monitoring the DC output with a volt meter from the IF port of the mixer? Sure beats $20,000 for a fancy HP. Of course this is a very simple method and is boring as heck to sit and watch a voltmeter but it

Re: [time-nuts] GPSDO Alternatives

Most of the choices I've seen here mention the Tbolts, 3801, 3805, etc, but I have never seen anyone mention the TrueTime XL-AK. It advertises 40 nsec 1 pps. Frequency as 1 x 10-12 per day. I have one and it seems to work well but have no way to test it against anything else yet. It has four

Re: [time-nuts] Surge Arresters

Unfortunately, many of the surge arresters available on ebay do not pass DC or have a DC shunt to ground internally. This means they won't work with an amplified antenna. Make sure any suppressor you get will pass the DC current to the antenna. Al, K9SI, retired ___

Re: [time-nuts] High Power LED Light power supply...

I spent many years as an electrician/electronics technician in a performing art center. Many artists would simply not practice or perform under fluorescent light because of the supposed flicker issue. Many of those who had no choice complained about it. Dancers were the worst. Al, k9si

Re: [time-nuts] Hi Power LED Light power supply...

The LED traffic signals around here are super noisy electrically. They rip up my mobile gear from the AM broadcast band through 2 meters any time we are close to a traffic light. Some are worse than others. If you can find out who makes them then avoid that manufacture like the plague. Al,

Re: [time-nuts] Zero-Crossing Detector Design?

The reason I suggested using a schmidt trigger gate is that a schmidt trigger gate switches states at different points at its input. That is, the input positive going switch point is higher than the negative going switch point, maybe half a volt or so. So, driving this gate with a volt RMS or

Re: [time-nuts] Zero-Crossing Detector Design?

Chris, The simplest zero crossing detector would be to feed your 1 volt, 10 mHz from the XL-DC into the input of an IC with schmidt trigger inputs. You would need to provide a series coupling cap and probably some DC bias from a pot to adjust symmetry of the output. I would also think that i

Re: [time-nuts] Phase modulation detection/NIST plan

Confucius say: "Man with two clocks never know what time it is." Al Every piece of equipment in our house shows a different time. I wouldn't complain if they all automatically adjusted. My current solution is to just stop looking at the clocks, and it's amazing how much easier life gets if y