I have two "atomic clocks": one is a La Crosse LCD unit, the other an "analog" wall clock whose hands are driven by a WWVB-sync 1xAA-powered mechanism. Following the recent "let's screw with everybody's clocks" cycle neither of my "atomic clocks" caught it, and I was reminded that I was Going To Fix This Problem last time. And the time before...
After some years I've discovered that, if I place my clocks near the west-most window and leave them for a few days, they will usually re-sync with the current WWVB time; if I don't do this it may be weeks or months before they pick up a strong enough signal to reset. This isn't a particularly onerous task, but it's only slightly less effort than pushing buttons in some arcane sequence to manually update a clock.
Is there some simple way of strengthening the WWVB signal so my clocks will reset themselves automatically, preferably one that doesn't involve stringing wires to each device?
The main axis of the house is a few degrees clockwise from a true E-W line. What I picture is an antenna near the westernmost window to pick up, amplify slightly (no kilowatt linears! ) and and rebroadcast the WWVB signal directionally "down" (east) the house so that every device would get a stronger signal. Is there some commercial gadget that does this? Or would I need to roll my own?
And, if I have to build it, what would be a good unidirectional LF antenna type? I have two neighbors to my SW and NW, and I really don't want to mess up their equipment.
I don't seem to be the only one with this problem, as these threads indicate:
Suggestions welcome.
Frank McKenney
--
Apologizing for our past sins may reveal character and for a time
lessen anti-Americanism abroad, but if it is done without
acknowledging that the sins of America are the sins of mankind, and
that our remedies are so often exceptional, then it only earns
transtory applause -- and a more lasting contempt that we ourselves
do not believe in the values we profess.
-- Victor Davis Hanson / The Father of Us All: War and History
I used a multi-turn 8" loop antenna encased in 1/2" copper pipe (with a fiber joint to avoid a shorted turn.
At the time I found fluorescent lighting to be the main PITA that obscured the signal.
So get as far away from fluorescent as you can.
Perhaps make a huge parasitic tuned loop to boost the signal strength?
For my PC's I use...
Perhaps you can use that and your own transmitter (as one of your own links mentioned) to re-sync your clocks.
Now that I'm located well outside the city noise maybe I should take a look at the 60kHz signal strength here. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
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I love to cook with wine. Sometimes I even put it in the food.
The real problem with various LF signals these days is the interference from all kinds of electric gadgets such as SMPS.
I live at the edge (1600 km) of the Mayflingen (Frankfurt Germany)
77.5 kHz transmitter range and have a lot of problems receiving it in an city apartment building, even when located at the window, far away from any electric circuits. However, I use to take the clock for a "walk in a park" after dark and it synchronize within half an hour. At my summer cottage, the clock will track the normal/summer time change usually in a few minutes.
While I do not have a clock for the 16 kHz Rugby UK station, I have monitored the signal (distance 1850 km) with an LF receiver and a wire hanging in a few trees at my summer cottage and the signal sounded quite clean even during daytime in the summer.
Since the essential thing is keeping the noise level down at the primary receiver. One idea would be to use a _battery_powered_ receiver far from any electric wiring or electronic gadgets feeding the extracted signal to a Bluetooth or similar narrow band link with perhaps 1 mW of transmitter power and hence long battery life, especially if operated only a few minutes each hour.
In the house, use the received Bluetooth signal to amplitude modulate a local 60 kHz oscillator radiating a few meters to the receivers.
Of course, you must be careful to avoid any feedback from your in-doors transmitter to the primary receiver, since both operate on the same frequency.
Square/rectangular, yes? Or is there some easy way to bend Cu pipe into a nice, pretty circle?
I've seen coils of coax used for the same purpose. ( But I'm letting myself get distracted. )
As far as Congress will let me (which isn't all that far). A decade back I had one fluorescent fixture over my kitchen sink (west wall) and one over my workbench in the basement (east wall less a few feet). Now I have two in the kitchen, three in the den, one in the main hall and bathroom, and more somewhere else. Still, our Congress wouldn't have mandated replacing incandescents with fluorescents without setting a noise standard low enough so the new bulbs couldn't _possibly_ interfere with WWVB, yes?
( As an aside, I just replaced a 20W fluorescent in a basement overhead recessed fixture and found I'd dated the old one "30JUN2013". Nine months -- maybe I'll make up the losses in volume. Sigh. )
When I attempted to access that file on your computer the NSA told me to use this one instead:
formatting link
( To guote Foghorn Leghorn, "Thatssa _jowk_, suhn." )
I'll be curious to hear what you find. Must be nice to be away from a large city. ... Hm. If strip mining techniques can level a mountain and heap it up elsewhere, how hard would it be to use the same approach to relocate a city like, say, Washington, DC? We could put it out in some out-of-the-way location such as, say, Death Valley...
Wouldn't solve my WWVB problem, but it might be nice anyway.
Frank
--
If you look up "human error" in the professional literature, you will
find that it has been largely replaced with the term "human
reliability." This is not mere political correctness; it stems from the
realization that mistakes are an irreducible subset of performance.
On this earth, humankind is only perfectable up to a point; designing
your systems on the assumption of uniform excellence is to offer up your
whole enterprise as a hostage to fallability.
-- Michael and Ellen Kaplan / Bozo Sapiens: Why to Err is Human
You need a friend who has a sheet metal roller that has a tubular slot in it ;-)
(I'm of that old era where boys were required to take shop courses in Jr. High and High School, so I know how to run all that equipment. I was one of the very few students at MIT granted authorization to use the shop machines in MIT's Building 20.)
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
What about the massive influx of Compact Fluorescent bulbs? Or has Germany avoided the U.S. effort to Replace The Evil Incandescent?
Thank you for the image of you taking your electronics for a walk in the park... and being included in a George Seurat painting.
Ah. Interesting: LF receiver ==> HF transmitter, then HF receivers ==> LF transmitters. That approach gets me around the problem of running coax -- and, more importantly, crawling around in my attic -- but adds a bit of overall cost: last time I checked, 3x Bluetooth modules would run me about $90US.
Still, it's a nice idea. Thank you. I need to think about this a bit.
Frank
--
The belief that human tastes are reversible cultural preferences has
led social planners to write off people's enjoyment of ornament,
natural light, and human scale, and force millions of people to live
in drab cement boxes. The romantic notion that all evil is a
product of society has justified the release of dangerous
psychopaths who promptly murdered innocent people. And the
conviction that humanity could be reshaped by massive social
engineering projects led to some of the greatest atrocities in
history. -- Steven Pinker, Preface to "The Blank Slate"
In fact you could do with any voice grade (0.3 - 3 kHz) radio (Bluetooth, Walkie talkie etc.). The primary receiver could be a direct conversion receiver with a local oscillator running at 59 or 61 kHz. This will create a beat tone at 1 kHz which can then be transferred using the voice grade radio link into the house.
In the house, you need an 59 or 61 kHz oscillator and an amplitude modulator.
A simple amplitude modulator will produce an additional sideband at 58 or 62 kHz, but this should not harm the indoor clocks.
The main question is, is a single sideband receiver needed at the main receiver or is a double sideband receiver sufficient. If the band is sufficient quiet at 56-58 or 62-65 kHz is quiet, even a simple DSB receiver would be enough. If you use a tuned loop, this can be used to attenuate the image response.
Take a look at example circuits using the NE602 oscillator/mixer chip, which could be used both as the primary receiver as well as the indoor transmitter (possibly beefed up by a single amplifier stage).
The signal is simple pulse amplitude modulation with the information content in the pulse width...
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
The format seems to be similar to Rugby or Mayflingen codes.
My main point of using some audio frequency method for the downlink radio was the avoidance of transferring any DC contents on the link.
Since apparently the ordinary clock receivers are not very picky about the actual carrier frequency, a slightly detuning between the primary receiver and the indoor transmitter would in fact be a good thing, since this reduces the risk for feedback from the indoor transmitter to the outdoor primary receiver.
I have used several hula hoops for various loop antennas. Of course the simplest case was a single turn HF loop with RG-58 coax (with a break in the shield at the top to avoid the short).
I also tried an MF loop made of a ribbon cable (offset by one each turn) to make a multiturn loop, but the stray capacitance was far too great for any MF operation, putting the resonance frequency below the MF band, but this might be acceptable for LF or ELF operation.
On a sunny day (Fri, 14 Mar 2014 10:16:45 -0500) it happened Frnak McKenney wrote in :
It is Ferry Simple to build a good GPS clock. I just did that :-) one dealextreme GPS module one PIC 18F14K22
1 OLED module Ant Jou Neet Power Too (5V 70 mA)
You could think about re-transmitting the time frame (modulating it), Jim already showed the format, its simple. I get UTC time and date, but that shoot not be that Diffy Cult to change to local time based on position.
Personally I have Ferry Goot LF reception here, even with bad wall warts.
That was in late 2012 that WWVB added phase modulation and broke many WWVB receivers. If that's your problem, there are a few fixes, but I suspect they're only useful for higher end receivers.
Sounds like interference. I have the same problem at both my house and my office. I have about 6 assorted WWVB receivers, all of which do not like being near any switching power supply, CCFL lamp, some LED lamps, solar inverters, etc. I built a 60KHz sniffer out of a loopstick cannibalized from one of my cheap receivers that didn't make it through the 2012 transition. I got lazy and just attached it to portable oscilloscope and retuned it to 60KHz to compensate for the scope probe capacitance. Wandering around the house, I identified some of the major noise source. I later did the same test with a larger 60 KHz loop antenna. Don't try this with a shielded loop as I was looking for the magnetic component of the signal, not the electric.
The article provided by Neon John: is the best I've seen. However, methinks some explanation of what's happening might be useful. You probably have noticed that 60 KHz antennas come in various sizes. There are tiny solenoid wound loopsticks that fit inside wristwatches. There are typically 8-10mm diameter ferrite rods and coils in various lengths. There are large unshielded loops and there are large shielded loops. However, if you test these devices in an area free from EMI interference, you'll probably find that they all have approximately the same field strength sensitivity when operating a given receiver. I've only compared a large home-made loop with a ferrite loopstick rod antenna, and they were (as far as I could tell) the same.
So, what's the difference? Well, the unloaded Q of the various antennas are different. My guess(tm) is about: wristwatch antenna 50 loopstick rod 100 shielded loop 200 Loaded Q is less, and often as low as 1/2 of the unloaded Q. In this case, the Q determines how much extraneous noise the receiver has to deal with. Higher Q picks up less noise, is generally better, but can have a problem with temperature drift. Use only the best capacitors. Too much Q is also a problem if you want to receive other time stations without retuning the antenna. Somewhere between 50 and 100 seems about right. Most better receivers use shielded loops. However, the noise reduction is not just from the increased Q of the loop. It's also because such large loops are usually mounted outside, away from the switching power supplies. They're also magnetically shielded and thus are immune to direct (transformer) coupling from inductors and xformers.
In short, if you want to get rid of the interference problem, get a better antenna and/or move the antenna away from the interference sources.
As you note, propagation varies with the time of day. In general, the best signals are when both the transmitter and receiver are at night. (A working Java is required). What the graphs mean is that it's not going to update at some times of the day, no matter how good a location or hardware you are using. Interestingly, you'll find that
60 KHz propagation does not exhibit short term fades and dropouts that are so common on the higher shortwave frequencies with WWV.
Bidirectional is usually good enough. Loop yagi style constructs are impractical because the element spacing will need to be about 1/4 wavelength apart, which at 60 KHz is about 1,250 meters. Some kind of phasing contraption using two loops and null out a single direction if you're dealing with a difficult noise source, such as an arcing power line insulator also won't work. Getting the loops far enough apart might be difficult. Too close, and they hear the same signals and cancel everything.
Build a 60 KHz sniffer and see if they really are a problem. My bet is that if you have interference problems, it's local.
Incidentally, there's a small chance you'll run into something like these solar micro-inverters: They switch at 50 KHz, but communicate low speed data to a computah with a 60 KHz carrier. I haven't seen one yet, but I'm told that they do cause WWVB problems.
Good luck.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Aha! I didn't know about that phase modulation addition. Reading here....
the way they did it will raise havoc with the synchronous AGC AM detection schemes used in most old clocks, and in my old chip design...
I'll have to muse over that and see if there's a solution. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
I don't think battery operation will help much. At the low power requirements for a WWVB front end, a simple analog power supply should be adequate. If you're worried about conducted emissions from the power lines, then there are various power line filters and ferrite beads that should help.
Ummm... Bluegoof has an end to end latency of about 150 msec. I've measured end to end audio latency at up to about 300 msec with various BT devices. With such an arrangement, your clock will be about 1/4 second behind. However, you can use an AptX codec, which reduces the end to end latency to a claimed 32 msec. However, if you don't need this level of precision, you can probably ignore the added latency.
Good luck. Self interference will certainly be a problem.
The occupied bandwidth of WWVB is about 5 Hz (shortest pulse width is about 200 msec). The LW (long wave) frequencies are really noisy from EMI and atmospheric noise (mostly lightning crashes). This noise and interference are the major limitation to decent reception. Retransmitting on a nearby frequency isn't going to work well. Besides, it would be classified as an intentional radiator (FCC Part
19.something) which restricts the transmit power and operating frequencies. The possibility of interference to itself and other time receivers doesn't make this a very attractive idea.
Instead, mix and upconvert the WWVH signal to some other much higher frequency. Pick something in the HF ham bands for testing. Power line communications for telephone extensions works well enough at HF frequencies. A single antenna and TRF (tuned RF) receiver, with the
60Khz amplifier signal fed to an upconverter (mixer), could feed the entire house. Install downconverters (mixers) that feed various clocks and devices, or just decode the WWVB data directly at the higher HF frequency. The waveform will be exactly the same as what the receiver produces. Big advantage is that since this secheme does not decode and re-modulate, there's very little added time delay.
You can also isolate the receiver from the displays with optical fiber. No need for anything elaborate. Just an IR LED and photo detector that will operate at 60 KHz. Amplify, maybe add some AGC (automatic gain control), and feed the LED emitter directly. If you don't like fiber, then do it with infrared "free space" communications and some optics.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
A bit more on power line emissions and WWVB: The whip antenna is tunable and run from an AC power supply. However, the conducted junk from the power line made 60 KHz reception rather problematic, until the author added additional RF filtering and bypassing.
Some performance reports with a Spectracom 8206 antenna, which is a shielded ferrite rod type: Note that at some times of the day, the SNR is near zero making AM demodulation impossible.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Good thought. Unfortunately, I've had WWV/WWVB reception problems as long as I've lived here. I finally build a 1m dia tuned loop so my Heath Most Accurate Clock could reliably receive WWV 10MHz. That doesn't mean that the 2012 change didn't make things worse, it just means that it's hard for me to distinguish "a pain to reset before
2012" from "a slightly bigger pain to reset after 2012".
Good thought. As in, "make sure you're solving the right problem".
I must be misreading this. I was under the impression that a shielded loop was preferred for WWVB-ish signal detection because it _was_ less sensitive to E-field noise. Or am I missing something subtle here?
My analog clock has a WWVB-sync'ed movement like this one:
formatting link
and there isn't room inside it for much of an antenna. One might guess that the LaCrosse WS-8418 has a slightly larger antenna, but it would be a guess; I haven't had an excuse to take it apart (yet).
Thank you for the pointer. I've filed it for future reference. ( Do the Aerial Connection diagrams a-d look mislabeled to you? )
Agreed. I don't forsee ever needing instant mid-day updates, though.
If I can improve things to the point where it gets updated every night I'll be more than happy.
Good suggestion, but I think I was trying to say that I didn't want any signal amplifier I built to cause problems for my neighbors.
Well, if I build a 60Hz "sniffer" I should be able to find one if I have it.
Thank you for the suggestions.
Frank
--
Generations of students in the social sciences have been exposed
to entertaining lectures that point out how dumb everyone else
is, constantly wandering off the path of logic and getting lost
in the fog of intuition. Yet logical norms are blind to content
and culture, ignoring evolved capacities and environmental
structure. Often what looks like a reasoning error from a
purely logical perspective turns out to be a highly intelligent
social judgment in the real world. Good intuitions must go
beyond the information given, and therefore, beyond logic.
-- Gerd Gigerenzer / Gut Feelings: The Intelligence
of the Unconscious.
Do any of you know if this IC (CME8000) works with the new WWVB?:
CME8000 Datasheet:
formatting link
Quote: "...
9 Protocol recognition To get a fast information of the received protocol, after every power on the received signal will be compared with the chosen protocol. The bit stream is checked for pulses with characteristically pulse duration. To start a new protocol recognition it is necessary to reset via PON. ... WWVB is designed such that when S1, S2 selected WWVB, CME8000 scans automatically in parallel the 3 possibilities in JJY, WWVB and MSF. Once protocol identified is not WWVB, user should switch to its correct protocol setting and confirm once again on the correct setting in 60kHz. ... WWVB Signal: at minimum 1?V input voltage all 60 bit of the signal are decoded without failure and the frame marker and the position markers (800ms) are recognized also. A pulse of ~500ms is recognized as a binary
1 and a pulse of ~200ms is recognized as a binary 0. After reception of a complete string, including the frame marker, all bit are stored in the equivalent place in the shift register (bit 1 in cell1, bit 60 in cell 60). ..."
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