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Antenna for receiving WWV/10MHz: am I asking too much?
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 McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all) -- Physics is mathematical not because we know so much about the physical world, but because we know so little; it is only its mathematical properties that we can discover. -- Bertrand Russell -- |
Antenna for receiving WWV/10MHz: am I asking too much?
On Oct 8, 9:16 pm, Frnak McKenney
wrote: 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. Sounds like it's being masked by some type of noise, but this could just be from the signal being very weak. If you can hear other stations ok, it probably the propagation more than anything. Being that you can barely hear it on a regular receiver seems to bear this out. Unless a noise is local, and you are trying to null it, I see no real advantage to using a small loop vs whatever else. I would make sure you don't have any local noise. IE: powerline noise, etc. If you did, the loop would be a good antenna to null that noise as long as you can turn it. But if there is no local noise, and the noise you hear is atmospheric, then it's not going to matter much what you use. I've got a hunch that the propagation is just the pits for you right now. I wouldn't be surprised if you tried it in a couple of months and it worked ok.. If you hear it on the regular radio ok, the clock should too. If you can't hear it on the regular radio, the clock probably won't either, and there is probably not much you can do about it. There should be times that it comes in fairly decent though, depending on time of day, etc.. I would use what you hear on the regular receiver as to whether the signal is really there or not. Propagation on most of the HF bands has been fairly flaky the last few months. IE: I got on 40m in the daytime the last time I was in OK, and it was like I was on 20m.. Band was real stretched out, and pretty long skip zones. I'd miss the semi locals I'd usually talk to, and end up hearing stations 1000 miles away instead. MK |
Antenna for receiving WWV/10MHz: am I asking too much?
On Oct 9, 6:06 am, wrote:
On Oct 8, 9:16 pm, Frnak McKenney wrote: 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. Sounds like it's being masked by some type of noise, but this could just be from the signal being very weak. If you can hear other stations ok, it probably the propagation more than anything. Being that you can barely hear it on a regular receiver seems to bear this out. Unless a noise is local, and you are trying to null it, I see no real advantage to using a small loop vs whatever else. I would make sure you don't have any local noise. IE: powerline noise, etc. If you did, the loop would be a good antenna to null that noise as long as you can turn it. But if there is no local noise, and the noise you hear is atmospheric, then it's not going to matter much what you use. I've got a hunch that the propagation is just the pits for you right now. I wouldn't be surprised if you tried it in a couple of months and it worked ok.. If you hear it on the regular radio ok, the clock should too. If you can't hear it on the regular radio, the clock probably won't either, and there is probably not much you can do about it. There should be times that it comes in fairly decent though, depending on time of day, etc.. I would use what you hear on the regular receiver as to whether the signal is really there or not. Propagation on most of the HF bands has been fairly flaky the last few months. IE: I got on 40m in the daytime the last time I was in OK, and it was like I was on 20m.. Band was real stretched out, and pretty long skip zones. I'd miss the semi locals I'd usually talk to, and end up hearing stations 1000 miles away instead. MK Even with my antennas on a 150 foot tower there are times of day when WWV at 10 megacycles is not audible... This is just the way the daily propagation cycle is at 30 meters. My best advice is to put up a dipole for 30 meters, even if you have to bend the ends to make it fit your space... A horizontal dipole being balanced picks up less vertically polarized noise than vertical antennas... Getting the wire outdoors will help also... You are likely picking up lots of humm and buzz inside the building from various electrical and electronic devices... The other issue is whether your clock is actually able to synch with the WWV signal... You may have a defect in the clock... It would seem that 4 or 5 bars should have done the trick... denny / k8do |
Antenna for receiving WWV/10MHz: am I asking too much?
Denny wrote in news:1191956444.157030.11580@
22g2000hsm.googlegroups.com: The other issue is whether your clock is actually able to synch with the WWV signal... You may have a defect in the clock... It would seem that 4 or 5 bars should have done the trick... Presumably the LED meter indicates recieved power, not signal to noise ratio. Owen |
Antenna for receiving WWV/10MHz: am I asking too much?
"Owen Duffy" wrote in message ... Denny wrote in news:1191956444.157030.11580@ 22g2000hsm.googlegroups.com: The other issue is whether your clock is actually able to synch with the WWV signal... You may have a defect in the clock... It would seem that 4 or 5 bars should have done the trick... Presumably the LED meter indicates recieved power, not signal to noise ratio. Owen -------- That's good! Polarization was one of my thoughts. Also, how is the synch tone derived by the receiver? Maybe that part of the radio needs tweaking? One would think that seven segments out of ten should be sufficient. I'm assuming there are ten segments total. Ed, NM2K |
Antenna for receiving WWV/10MHz: am I asking too much?
Since he said previously that he could hardly hear the tones/voice, isn't it
probable that the receiver is just seeing mostly noise? As mentioned by someone else, propagation is currently "very ordinary" (aka poor) at present, so maybe he's just out of range. KeithM VK1ZKM "ecregger" wrote in message ... "Owen Duffy" wrote in message ... Denny wrote in news:1191956444.157030.11580@ 22g2000hsm.googlegroups.com: The other issue is whether your clock is actually able to synch with the WWV signal... You may have a defect in the clock... It would seem that 4 or 5 bars should have done the trick... Presumably the LED meter indicates recieved power, not signal to noise ratio. Owen -------- That's good! Polarization was one of my thoughts. Also, how is the synch tone derived by the receiver? Maybe that part of the radio needs tweaking? One would think that seven segments out of ten should be sufficient. I'm assuming there are ten segments total. Ed, NM2K |
Antenna for receiving WWV/10MHz: am I asking too much?
I am in New Jersey. Propagation from Colorado to here is probably similar to
Virginia. This morning, Tues, 10/9, I listened to WWV on 10 MHz with the 4 antennas I have at my disposal to see what kind of signal level I get. My antennas are 80 meter and 40 meter dipoles, a 20 meter yagi and a 30 meter dipole, all at about 50 feet. On the first 3 antennas WWV runs about S6-9, and on the 30 meter dipole it is 10-20 db over 9. This evening, 6 pm, the first 3 antennas haul WWV in at S9 and the 30 m dipole has it at a rock solid 30 over. So I agree with the advice you got to string up some kind of dipole and throw out that loop, there is plenty of signal, you just have to go get it. Rick K2XT PS may I throw in a little commercial for my pet peeve? As you read this did you notice that I did not include any text from previous posts? Did you miss it? |
Antenna for receiving WWV/10MHz: am I asking too much?
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Antenna for receiving WWV/10MHz: am I asking too much?
My understanding is to include the portion of the message that you are replying to (as I have done here) Danny, perfection. Absolute perfection. You de Man. Rick |
Antenna for receiving WWV/10MHz: am I asking too much?
Rick wrote:
I am in New Jersey. Propagation from Colorado to here is probably similar to Virginia. This morning, Tues, 10/9, I listened to WWV on 10 MHz with the 4 antennas I have at my disposal to see what kind of signal level I get. My antennas are 80 meter and 40 meter dipoles, a 20 meter yagi and a 30 meter dipole, all at about 50 feet. On the first 3 antennas WWV runs about S6-9, and on the 30 meter dipole it is 10-20 db over 9. This evening, 6 pm, the first 3 antennas haul WWV in at S9 and the 30 m dipole has it at a rock solid 30 over. So I agree with the advice you got to string up some kind of dipole and throw out that loop, there is plenty of signal, you just have to go get it. Rick K2XT PS may I throw in a little commercial for my pet peeve? As you read this did you notice that I did not include any text from previous posts? Did you miss it? ----------- Some of us include the previous post's text because we can't remember what we're answering unless we can refer to it while writing. You too will grow old someday, if you live so long. G Ed Cregger, NM2K |
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