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#1
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On Tue, 09 Oct 2007 02:16:37 -0000, Frnak McKenney
wrote: Am I asking too much? Hi Frnak, Judging by the questions and responses, I would have to say "Yes." To this point you haven't exactly demonstrated you have a problem, just a complaint of a signal of poor quality to a human's perception. For the clock itself, that complaint is arguably weak. Let's just examine the evidence for the problem: There is none! You have a clock that has 100mS resolution, and yet you have never said how much it is off. 100mS? 1S? 10S? 1 minute? 1 Hour? All, or any part of any of these metrics? As Reggie would have chimed in at this point "If you can't measure it and express it with a quantifiable, then you don't know anything." Of course, your only source of accurate information is the one you are suggesting has a problem. It probably doesn't have a problem, but then how does one use this source's accuracy to check itself? You would need a second clock to check it, and we would be hearing your complaint in stereo. I've calibrated time standards to the nearest 100nS and it is accomplished at one sitting, no need for total connectivity such as you might imagine (unless the clock you have is especially crappy). Your clock has a resolution of 0.1 second. There are roughly 1 million ticks of the display in a day. A simple XTAL oscillator at 10 MHz would exhibit 50ppm stability and in a day wander up to 0.5 second. The next day it might wander back, the day following it might slip below by 0.5 second. You would be hard pressed to confirm this with over the air matching to the strike of the WWV gong - except if the clock is especially crappy (and it could be). The same XTAL might also exhibit an absolute error of 50ppm and accumulate time error. This would be far more noticeable over the course of a week (you could confirm the error by listening to time announcements - but you have been silent to this issue). These worst case errors all presume that the internal circuitry cannot over the course of 24 hours manage to pull out one of 1400 synchronizing opportunities to phase lock out the error. These circuits are generally optimized to accomplish just this (they work fine in watches with a 60KHz signal after all). Your clock may be especially crappy (but that is unlikely). The clock synchronizing circuits don't have to listen to the bandwidth of noise you hear, the speaker is for your convenience, not the clock's. I am sure that it works fine with only 1 LED lit - this is not a case of "can you hear me now?" 73's Richard Clark, KB7QHC |
#2
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On Wed, 10 Oct 2007 10:19:49 -0700, Richard Clark wrote:
On Tue, 09 Oct 2007 02:16:37 -0000, Frnak McKenney wrote: Am I asking too much? Hi Frnak, Judging by the questions and responses, I would have to say "Yes." To this point you haven't exactly demonstrated you have a problem, just a complaint of a signal of poor quality to a human's perception. For the clock itself, that complaint is arguably weak. Let's just examine the evidence for the problem: There is none! You have a clock that has 100mS resolution, and yet you have never said how much it is off. 100mS? 1S? 10S? 1 minute? 1 Hour? All, or any part of any of these metrics? It's hard to tell exactly how much the clock is off by. Every time the power hiccups, or I have to move the MAC-II, or power down the outlet the display switches to something like this (best viewed with a fixed-width font): _ _ _ _ /_ /_ /_ /_ / / /_/ /_ _/ /_ /_ and it stays that way for weeks. Or months. As Reggie would have chimed in at this point "If you can't measure it and express it with a quantifiable, then you don't know anything." Given the extent of my ignorance concerning 'most everything, that seems likely. grin! Of course, your only source of accurate information is the one you are suggesting has a problem. It probably doesn't have a problem, but then how does one use this source's accuracy to check itself? You would need a second clock to check it, and we would be hearing your complaint in stereo. Hm... I don't _think_ so. At least, I havent heard of any plans for a High-Def upgrade to Usenet lately, but with Congress currently in session I suppose anything is possible. As for testing the clock's accuracy, you're right about needing a second source ("Qui custodiet ipsos custodes?" or something like that? grin). On the other hand, as long as the digits are flashing by, I'm happy to "just trust them". I've calibrated time standards to the nearest 100nS and it is accomplished at one sitting, no need for total connectivity such as you might imagine (unless the clock you have is especially crappy). Your clock has a resolution of 0.1 second. There are roughly 1 million ticks of the display in a day. A simple XTAL oscillator at 10 MHz would exhibit 50ppm stability and in a day wander up to 0.5 second. The next day it might wander back, the day following it might slip below by 0.5 second. If I read the MAC-II manual correctly, each time it "connects to WWV" (gets a recognizable signal) it calculates and saves an adjustment value. The front panel has two LEDs labelled "TRIM UP" and "TRIM DN" to indicate how well it's doing. ... You would be hard pressed to confirm this with over the air matching to the strike of the WWV gong - except if the clock is especially crappy (and it could be). The same XTAL might also exhibit an absolute error of 50ppm and accumulate time error. This would be far more noticeable over the course of a week (you could confirm the error by listening to time announcements - but you have been silent to this issue). True. And, while I'm sure the _WWV_ announcer hasn't been silent, _I_ haven't heard anything comprehendable from him/her/it out of my MAC-II's speaker at any point in the past few weeks. These worst case errors all presume that the internal circuitry cannot over the course of 24 hours manage to pull out one of 1400 synchronizing opportunities to phase lock out the error. These circuits are generally optimized to accomplish just this (they work fine in watches with a 60KHz signal after all). Your clock may be especially crappy (but that is unlikely). Based on the feedback from other posters, it's likely a consequence of 10MHz propagation. A VLF RF signal like 60KHz reportedly does a much better job of getting a readable signal to a wide area. The clock synchronizing circuits don't have to listen to the bandwidth of noise you hear, the speaker is for your convenience, not the clock's. I am sure that it works fine with only 1 LED lit - this is not a case of "can you hear me now?" No, but (assuming you're subbing for WWV grin!) it would be nice to know I was going to get a readable message from "you" more than once every couple of months. (Why do I hear the echo of my parents' frustration during my colege days? grin!) Thanks for the feedback. I admit I hadn't thought that much about the accuracy of the MAC-II; I'm afraid I've been too caught up in simply trying to get digits instead of "error text" on the display. Frank -- "A good traveller has no fixed plans and is not intent on arriving." -- Lao Tzu (570-490 BC) -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all) |
#3
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On Thu, 11 Oct 2007 12:12:14 -0000, Frnak McKenney
wrote: _ _ _ _ /_ /_ /_ /_ / / /_/ /_ _/ /_ /_ and it stays that way for weeks. Or months. A whip antenna should be able to sort out WWV for at least one of 1400 synchronizing events in a day. This may be a problem of too much antenna at one time - and a nearby lightning event at that same time. Your front end got fried out. 73's Richard Clark, KB7QHC |
#4
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On Thu, 11 Oct 2007 07:51:55 -0700, Richard Clark wrote:
On Thu, 11 Oct 2007 12:12:14 -0000, Frnak McKenney wrote: _ _ _ _ /_ /_ /_ /_ / / /_/ /_ _/ /_ /_ and it stays that way for weeks. Or months. A whip antenna should be able to sort out WWV for at least one of 1400 synchronizing events in a day. This may be a problem of too much antenna at one time - and a nearby lightning event at that same time. Your front end got fried out. If you're reading these posts in the same order I'm posting, you'll have already read my good news: It's Working! (Oh. That's right -- this is Usenet. Y'all can't here the "doooonb"-ing from down the hall. Well, take my word for it -- or even the MAC-II's display! grin) This doesn't prove that the MAC-II's J-FET RF amplifier hasn't been degraded through an... er, "very wideband RF overload" grin!, but I think it does say that "completely fried" is unlikely (which pleases me greatly! grin). My earlier MAC-I had a nice whip built in, and could select the strongest signal among (IIRC) 5, 10, and 15MHz, but it had the same problems getting an "acceptable" WWV signal most of the time. Frank -- "Whatever you can do, or dream you can, begin it. Boldness has genius, power and magic in it" -- Goethe -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all) |
#5
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Frnak McKenney wrote:
Hm... I don't _think_ so. At least, I havent heard of any plans for a High-Def upgrade to Usenet lately, but with Congress currently in session I suppose anything is possible. As for testing the clock's accuracy, you're right about needing a second source ("Qui custodiet ipsos custodes?" or something like that? grin). On the other hand, as long as the digits are flashing by, I'm happy to "just trust them". One needs three clocks.. if you have only two, you only know that they differ. If you have three, you can detect the failed clock, because the other two read the same time. Of course, if the different clocks have different accuracies or reliabilities, that's another story. For a more detailed treatment of such things, you might want to check out the "Byzantine General" problem. Based on the feedback from other posters, it's likely a consequence of 10MHz propagation. A VLF RF signal like 60KHz reportedly does a much better job of getting a readable signal to a wide area. Although in my house (southern California), the 60 kHz signal seems to fade in and out on a daily basis. |
#6
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On Thu, 11 Oct 2007 09:52:53 -0700, Jim Lux wrote:
Frnak McKenney wrote: --snip-- As for testing the clock's accuracy, you're right about needing a second source ("Qui custodiet ipsos custodes?" or something like that? grin). On the other hand, as long as the digits are flashing by, I'm happy to "just trust them". One needs three clocks.. if you have only two, you only know that they differ. If you have three, you can detect the failed clock, because the other two read the same time. Well, you have a reasonable _presumption_, anyway. grin In _theory_, one could have two clocks in error and one on time. Or even all three out of step with (say) the NIST's clock. But two-out-of-three would be the place to put your money. grin Of course, if the different clocks have different accuracies or reliabilities, that's another story. For a more detailed treatment of such things, you might want to check out the "Byzantine General" problem. Faint recollections... "unreliable communication on the battlefield" category? Based on the feedback from other posters, it's likely a consequence of 10MHz propagation. A VLF RF signal like 60KHz reportedly does a much better job of getting a readable signal to a wide area. Although in my house (southern California), the 60 kHz signal seems to fade in and out on a daily basis. I can believe it. I've seen those LCD "clock and weather" stations take days to synchronize the time (I assume they're using WWVB). OTOH, I'm hardly one to talk, since I've let the MAC-II sit liostening for months at a time without successfully locking-in on WWV. Frank -- Hanlon's Razor: ÿNever attribute to malice that which can be adequately explained by stupidity.ÿ -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all) |
#7
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On Oct 11, 5:12 am, Frnak McKenney
wrote: On Wed, 10 Oct 2007 10:19:49 -0700, Richard Clark wrote: On Tue, 09 Oct 2007 02:16:37 -0000, Frnak McKenney wrote: Am I asking too much? Hi Frnak, Judging by the questions and responses, I would have to say "Yes." To this point you haven't exactly demonstrated you have a problem, just a complaint of a signal of poor quality to a human's perception. For the clock itself, that complaint is arguably weak. Let's just examine the evidence for the problem: There is none! You have a clock that has 100mS resolution, and yet you have never said how much it is off. 100mS? 1S? 10S? 1 minute? 1 Hour? All, or any part of any of these metrics? It's hard to tell exactly how much the clock is off by. Every time the power hiccups, or I have to move the MAC-II, or power down the outlet the display switches to something like this (best viewed with a fixed-width font): _ _ _ _ /_ /_ /_ /_ / / /_/ /_ _/ /_ /_ and it stays that way for weeks. Or months. As Reggie would have chimed in at this point "If you can't measure it and express it with a quantifiable, then you don't know anything." Given the extent of my ignorance concerning 'most everything, that seems likely. grin! Of course, your only source of accurate information is the one you are suggesting has a problem. It probably doesn't have a problem, but then how does one use this source's accuracy to check itself? You would need a second clock to check it, and we would be hearing your complaint in stereo. Hm... I don't _think_ so. At least, I havent heard of any plans for a High-Def upgrade to Usenet lately, but with Congress currently in session I suppose anything is possible. As for testing the clock's accuracy, you're right about needing a second source ("Qui custodiet ipsos custodes?" or something like that? grin). On the other hand, as long as the digits are flashing by, I'm happy to "just trust them". I've calibrated time standards to the nearest 100nS and it is accomplished at one sitting, no need for total connectivity such as you might imagine (unless the clock you have is especially crappy). Your clock has a resolution of 0.1 second. There are roughly 1 million ticks of the display in a day. A simple XTAL oscillator at 10 MHz would exhibit 50ppm stability and in a day wander up to 0.5 second. The next day it might wander back, the day following it might slip below by 0.5 second. If I read the MAC-II manual correctly, each time it "connects to WWV" (gets a recognizable signal) it calculates and saves an adjustment value. The front panel has two LEDs labelled "TRIM UP" and "TRIM DN" to indicate how well it's doing. ... You would be hard pressed to confirm this with over the air matching to the strike of the WWV gong - except if the clock is especially crappy (and it could be). The same XTAL might also exhibit an absolute error of 50ppm and accumulate time error. This would be far more noticeable over the course of a week (you could confirm the error by listening to time announcements - but you have been silent to this issue). True. And, while I'm sure the _WWV_ announcer hasn't been silent, _I_ haven't heard anything comprehendable from him/her/it out of my MAC-II's speaker at any point in the past few weeks. These worst case errors all presume that the internal circuitry cannot over the course of 24 hours manage to pull out one of 1400 synchronizing opportunities to phase lock out the error. These circuits are generally optimized to accomplish just this (they work fine in watches with a 60KHz signal after all). Your clock may be especially crappy (but that is unlikely). Based on the feedback from other posters, it's likely a consequence of 10MHz propagation. A VLF RF signal like 60KHz reportedly does a much better job of getting a readable signal to a wide area. The clock synchronizing circuits don't have to listen to the bandwidth of noise you hear, the speaker is for your convenience, not the clock's. I am sure that it works fine with only 1 LED lit - this is not a case of "can you hear me now?" No, but (assuming you're subbing for WWV grin!) it would be nice to know I was going to get a readable message from "you" more than once every couple of months. (Why do I hear the echo of my parents' frustration during my colege days? grin!) Thanks for the feedback. I admit I hadn't thought that much about the accuracy of the MAC-II; I'm afraid I've been too caught up in simply trying to get digits instead of "error text" on the display. Frank -- "A good traveller has no fixed plans and is not intent on arriving." -- Lao Tzu (570-490 BC) -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all) Gee, all this trouble you're having getting a good signal from WWV on 10MHz makes me wonder, "why??" I mean, why bother? It must be the challenge! I'm a bit closer to Ft. Collins, but I wouldn't expect things to be all that much different, and in any event, the same antenna I've used for them has worked fine for signals from W1AW, for frequency measuring tests. That antenna is just a short piece of wire, maybe five feet long, connected to a signal analyzer's input port. The signal analyzer's input doesn't even have a particularly good noise figure. But with it, I get a good enough signal from WWV to easily track the nocturnal/diurnal frequency shifts that happen as the path length changes. (The analyzer may not have a great RF front end, but it has a very stable frequency reference...) Similarly, I have a portable short wave radio that has an awful front end, and with just a 3 foot whip antenna, it gets WWV 10MHz fine most of the time. Obviously, there are times of the day when propagation just doesn't do it, but over the period of one day, and not during a geomagnetic storm, the signal is usually available. All this makes me wonder if the receiver in your clock is OK. I'd start by looking at that; or at very least, see if a known-working radio receiver has as much trouble with the signal as the clock seems to. Given that the clock has a single frequency receiver, even a pretty simple receiver design should give decent performance. It's also possible that you have some signal source on nominally 10MHz nearby, and you hear than instead of WWV. There are soooo many microprocessors around the average home these days that it's entirely possible that the source of the trouble is very nearby--but could also be in a neighbor's house (or car -- or garage -- or ??). If you want an accurate clock and get tired of fooling with WWV-10MHz, and don't want to use WWVB-60kHz, you might consider using a GPS. As long as you can manage an antenna with a reasonably clear view of the sky, you should be able to have a clock reliably set to within less than a second accuracy practically all the time. Or, if you'd like to be independent of external references, modify your MAC with an oven oscillator. Oven stabilized crystal oscillators left on for a long time will almost always settle out to very low drift rates---one part in 10^8 over a year shouldn't be difficult, in my experience, and GPS signals can be used to calibrate it occasionally. One part in 10^8 is about 1/3 of a second per year. Cheers, Tom |
#8
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On Thu, 11 Oct 2007 11:26:03 -0700, K7ITM wrote:
On Oct 11, 5:12 am, Frnak McKenney wrote: On Wed, 10 Oct 2007 10:19:49 -0700, Richard Clark wrote: On Tue, 09 Oct 2007 02:16:37 -0000, Frnak McKenney wrote: Am I asking too much? Hi Frnak, Judging by the questions and responses, I would have to say "Yes." --snip-- Gee, all this trouble you're having getting a good signal from WWV on 10MHz makes me wonder, "why??" I mean, why bother? It must be the challenge! I'm a bit closer to Ft. Collins, but I wouldn't expect things to be all that much different, and in any event, the same antenna I've used for them has worked fine for signals from W1AW, for frequency measuring tests. That antenna is just a short piece of wire, maybe five feet long, connected to a signal analyzer's input port. The signal analyzer's input doesn't even have a particularly good noise figure. But with it, I get a good enough signal from WWV to easily track the nocturnal/diurnal frequency shifts that happen as the path length changes. (The analyzer may not have a great RF front end, but it has a very stable frequency reference...) Similarly, I have a portable short wave radio that has an awful front end, and with just a 3 foot whip antenna, it gets WWV 10MHz fine most of the time. Obviously, there are times of the day when propagation just doesn't do it, but over the period of one day, and not during a geomagnetic storm, the signal is usually available. Hm. Sounds great. All this makes me wonder if the receiver in your clock is OK. I'd start by looking at that; or at very least, see if a known-working radio receiver has as much trouble with the signal as the clock seems to. Given that the clock has a single frequency receiver, even a pretty simple receiver design should give decent performance. The RF section is a one-transistor (J-FET) amplifier followed by a TDA1072A "Integrated AM receiver" chip. I'm not sure how to go about comparing that to your equipment. It's also possible that you have some signal source on nominally 10MHz nearby, and you hear than instead of WWV. There are soooo many microprocessors around the average home these days that it's entirely possible that the source of the trouble is very nearby--but could also be in a neighbor's house (or car -- or garage -- or ??). Highly possible, but the noise level "at the speaker" seems to have fallen off appreciably in the past few days. Also, I think I'm doing a better job of tuning the antenna; adjusting with no clearly defined signal is a chicken-and-egg problem, but two days ago I started hearing a deafening cackle. grin! If you want an accurate clock and get tired of fooling with WWV-10MHz, and don't want to use WWVB-60kHz, you might consider using a GPS. As long as you can manage an antenna with a reasonably clear view of the sky, you should be able to have a clock reliably set to within less than a second accuracy practically all the time. Or, if you'd like to be independent of external references, modify your MAC with an oven oscillator. Oven stabilized crystal oscillators left on for a long time will almost always settle out to very low drift rates---one part in 10^8 over a year shouldn't be difficult, in my experience, and GPS signals can be used to calibrate it occasionally. One part in 10^8 is about 1/3 of a second per year. Yup. GPS would eb the way to go for accuracy... or -- for the billion-dollar-budget people -- your very own Cesium Clock. grin! Frank -- To learn is to change. Learning allows an animal child to finish the long, slow process of evolution by changing in its own lifetime. Tiger cubs, eaglets, or babies, nature brings us all into existence with the ability to learn, and the rest is up to us. -- Susan McCarthy / Becoming a Tiger -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all) |
#9
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Frnak McKenney wrote:
I'm in Richmond, Virginia and I'm trying to noticeably improve my reception of WWV's 10MHz signal from Fort Collins, Colorado. It all seemed so simple, two weeks ago: wind some wire, solder a connector, and Hey...presto! a clean WWV signal. grin! It wasn't so simple, and I'm afraid I've let it become an "ego thing" (see also: resource sink). I've outlined the problem below in the hope that someone can either suggest something I haven't already tried, or even point out something really dumb that I've been doing and shouldn't keep doing. grin! Background ---------- Several years back I inherited a Heathkit GCW-1001 Most Accurate Clock II from my father. This is an update to it's predecessor, Heath's GC-1000 Most Accurate Clock; its circuit, built around a Philips TDA1072A AM receiver IC and an 87C52 microprocessor, monitors WWV's 10MHz signal and decodes the BCD-coded 100Hz subcarrier (details at http://tf.nist.gov/stations/wwv.html) to keep the MAC-II accurate. This MAC-II worked fine for my father: he had a 30 meter dipole of some kind in the attic, above the second floor of a house on a hill. For him, WWV's 10MHz signal from Fort Collins came in regular as... well, "clockwork". igg! For me, in a one-story-plus-basement, in a low spot in a river valley, it's a different story. The GCW-1001 has a stack-o-LEDs signal strength indicator driven by the TDA1072's AGC output; it would wander between 2 and 4 LEDs with my 40" indoor dangling wire antenna, and it could take weeks or months for atmospheric conditions to randomly improve the signal to where the GCW-1001 could "lock in" a time. Two weeks ago, in a fit of madness, I decided to try building a better antenna, one which would let the clock lock onto WWV at least, say, once a week. The tuned-loop antenna I've built _has_ increased the signal -- I'm seeing 4-5 LEDs lit on a regular basis, and 6 on occasion -- but the clock still isn't sync'ing to WWV's time signal. The clock face remains at a cute(?) 7-segment "not SEt" display. And what seems to be louder is the carrier -- or _a_ carrier, at any rate -- but not the tones or the human voice time callout coming out of the GCW-1001's speaker. I seem to be up to my assets in alligators, and the swamp doesn't seem to be draining much. Problem ------- My main problem is that, although the GCW-1001's LED "Signal" stack _says_ it's getting a stronger signal, what I hear through the speaker monitor isn't _clearer_. There are long periods when I cannot hear any WWV tones through the GC-1001's speaker, the tones/ticks are faint even when there are 5-6 LEDs lit, and the voice is almost never audible/distinguishable. The clock _seems_ to be sync-ing a little more often (it's done it four times in the past two weeks), but I had hoped it might happen a _little_ more frequently. Am I asking too much? Is WWV's 10MHz signal from (say) 2,000 miles away, simply too weak to pick up solidly without an outdoor antenna? What I've tried --------------- My (second) attempt at a 30m indoor loop antenna: Main loop (tuned): A 36" near-circle of #12 insulated house wire with an AM/FM tuning capacitor across it. Pickup loop: One (36") turn of #27 magnet wire taped to the #12 loop with electrical tapegrin!. The ends (scraped and tinned) are tied to the GCW-1001's 50ohm antenna input with a couple of 12" clip leads and a 3' section of coax. The loops are mounted on (and held in shape by) a 1'x4'x0.5" "backboard" made of "blue foam" house insulation that I found in my basement; the loops are held in place by small plastic cable ties. The foam backing is resting against a (roughly) N-S wall, which _should_ orient the loop plane across the WWV wavefront for maximum pickup. Does this sound like a reasonable attempt at a tuned 10MHz loop? Is there any reason to believe that the foam backing would affect the loop inductance? I'm assuming it's a good insulator and nothing more, but that's an assumption. Is it possible that I'm picking up a non-WWV dignal so strong that it's masking WWV? I tried tuning around 10MHz with a shortwave radio; it didn't find WWV -- not a particularly hopeful sign -- but it did pick up a station called (IIRC) WWCR. WWCR's 'web site (www.wwcr.com) lists its transmitter #4 as using 9.985MHz and 9.975MHz between 0900 and 2100 CST. Any advice or suggestions will be appreciated, up to and including "You can't power a hedge trimmer from two AAA cells!". Thanks... Frank - I am up in Maryland, not too far from you. WWV on 10MHz is only usable for about a third or less of the day for locking an electronic clock. Generally the late afternoons and evenings are great, early afternoons and mornings are a little more variable. Overnight 5MHz works best. During the mid-day 15MHz or when propogation permits 20MHz rules for WWV. I don't think your Heath has any frequency diversity capability, right? Well, 10MHz is a pretty good choice if you only have a choice of one, it is usually coming in strong in the evenings there. Over wintertime 5MHz gets pretty good at night. You will, especially in the early morning, occasionally hear WWVH on 10MHz or 5MHz or 15MHz. Sometimes I hear both WWV and WWVH at the same time. You can recognize WWVH by the woman's voice reading the time. My best antenna for 10MHz WWV is my 40-meter dipole strung between two trees. Mine mostly points broadside to the NE/SW but if you could arrange it, it would be slightly preferable to have it broadside to be sensitive to the W. A dipole optimized for 10MHz would be even shorter - the formulas put a half wave dipole at 47 feet long. Tim. |
#10
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Tim,
Thanks for joining in. On Sat, 13 Oct 2007 17:27:01 -0700, Tim Shoppa wrote: Frnak McKenney wrote: I'm in Richmond, Virginia and I'm trying to noticeably improve my reception of WWV's 10MHz signal from Fort Collins, Colorado. It all seemed so simple, two weeks ago: wind some wire, solder a connector, and Hey...presto! a clean WWV signal. grin! --snip-- Frank - I am up in Maryland, not too far from you. WWV on 10MHz is only usable for about a third or less of the day for locking an electronic clock. Generally the late afternoons and evenings are great, early afternoons and mornings are a little more variable. Overnight 5MHz works best. During the mid-day 15MHz or when propogation permits 20MHz rules for WWV. I don't think your Heath has any frequency diversity capability, right? Well, 10MHz is a pretty good choice if you only have a choice of one, it is usually coming in strong in the evenings there. Over wintertime 5MHz gets pretty good at night. My current box, the MAC-II, only monitors 10MHz; its predecessor, the GC-1000 MAC, monitored (IIRC) 5/10/15MHz and chose the strongest. You will, especially in the early morning, occasionally hear WWVH on 10MHz or 5MHz or 15MHz. Sometimes I hear both WWV and WWVH at the same time. You can recognize WWVH by the woman's voice reading the time. My best antenna for 10MHz WWV is my 40-meter dipole strung between two trees. Mine mostly points broadside to the NE/SW but if you could arrange it, it would be slightly preferable to have it broadside to be sensitive to the W. A dipole optimized for 10MHz would be even shorter - the formulas put a half wave dipole at 47 feet long. Thanks for your signal report and the antenna suggestion. I'll keep it in mind. On the other hand, my tuned (and currently horizontal) loop is suddenly picking up WWV/10MHz remarkably reliably, and I didn't even have to "sacrifice a goat at midnight"! grin Has your reception improved lately as well (last few days)? Frank -- Writers listen for harmonies; civilians listen for melody alone. For them the facades of ordinary situations are opaque, and they see what is there to be seen. Writers are attracted to translucence. We start with nothing but an idea, an agitation, a compulsion, an irritation. That, plus a bumblebee's faith that it can fly. -- Hal Ackerman / Write Screenplays That Sell -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all) |
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