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#1
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Steve Nosko wrote:
Where are you? I'm in Illinois and just got one of the clocks. I know it helps you not not a bit for me to say mine sync'ed up quickly, but everybody says that kinda' stuff (:-).. Don't think there is anything to buy... Make is the only way. The instructions for mine say that it only listens at certain times and can take a few _DAYS_ to sync up. That seems strange to me...oh well. Ivan's passive loop is a VERY good idea - easy. I don't think cinder block walls will matter. Search for "lowfer". I wanted to actually hear WWVB and do a little SWLing for NDBs (300-500KHz) w/ my new IC 706 and did some snooping. A good loop takes a little bit of work. All you will hear is nothing, unless your detector and audio amp goes down to DC. The modulation rate is one bit per second, by reducing the carrier level by 10 dB. There is no audio modulation, because the signal is also a frequency standard. The only way you would hear it would be to mix a signal to beat against WWVB to produce a heterodyne in the radio's pass band. -- We now return you to our normally scheduled programming. Take a look at this little cutie! ;-) http://home.earthlink.net/~mike.terrell/photos.html Michael A. Terrell Central Florida |
#2
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![]() "Michael A. Terrell" wrote: Steve Nosko wrote: Where are you? I'm in Illinois and just got one of the clocks. I know it helps you not not a bit for me to say mine sync'ed up quickly, but everybody says that kinda' stuff (:-).. Don't think there is anything to buy... Make is the only way. The instructions for mine say that it only listens at certain times and can take a few _DAYS_ to sync up. That seems strange to me...oh well. Ivan's passive loop is a VERY good idea - easy. I don't think cinder block walls will matter. Search for "lowfer". I wanted to actually hear WWVB and do a little SWLing for NDBs (300-500KHz) w/ my new IC 706 and did some snooping. A good loop takes a little bit of work. All you will hear is nothing, unless your detector and audio amp goes down to DC. The modulation rate is one bit per second, by reducing the carrier level by 10 dB. There is no audio modulation, because the signal is also a frequency standard. The only way you would hear it would be to mix a signal to beat against WWVB to produce a heterodyne in the radio's pass band. -- We now return you to our normally scheduled programming. Take a look at this little cutie! ;-) http://home.earthlink.net/~mike.terrell/photos.html Michael A. Terrell Central Florida I hear it fine with several different receivers provided I use either CW or SSB. But! I CANNOT hear it on my IC-706; it does not seem to come alive until somewhere between 200 and 300kHz. Dave |
#3
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Dave Holford wrote:
I hear it fine with several different receivers provided I use either CW or SSB. But! I CANNOT hear it on my IC-706; it does not seem to come alive until somewhere between 200 and 300kHz. Dave Try using a HP312 series Frequency Selective Voltmeter for the receiver. Build a 60 KHz tuned loop and look at it with a scope. You can see the modulation, because it is so slow. It is a CW signal with a 10 dB gain reduction modulation with a maximum level change of twice per second. (Normal and -10 dB) I built a three foot square copper loop with an insulator where it was mounted on a cast aluminum electrical box, and wound 20 turns of wire inside the 3/4" copper pipe after it was soldered together. I used an op amp to give some gain,. and I could watch the modulation. The big problem was a neighbor about a half mile away left a TV set on 24/7 and the horizontal oscillator drifted after the station went off, and the harmonics would drift right through 60 KHz. I wanted to use it for a frequency standard, but I couldn't do it there. I will try it again, some day, now that I have a couple miles of woods between me and Colorado. I have enough gain to get around 12V P-P at the power inserter. I used 75 ohm cable and "F" fittings because they were handy, but I would use Mini Circuits MMICs and 50 Ohm cable if I built another outdoor 60 KHz antenna. -- We now return you to our normally scheduled programming. Take a look at this little cutie! ;-) http://home.earthlink.net/~mike.terrell/photos.html Michael A. Terrell Central Florida |
#4
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![]() "Michael A. Terrell" wrote: Dave Holford wrote: I hear it fine with several different receivers provided I use either CW or SSB. But! I CANNOT hear it on my IC-706; it does not seem to come alive until somewhere between 200 and 300kHz. Dave Try using a HP312 series Frequency Selective Voltmeter for the receiver. Build a 60 KHz tuned loop and look at it with a scope. You can see the modulation, because it is so slow. It is a CW signal with a 10 dB gain reduction modulation with a maximum level change of twice per second. (Normal and -10 dB) I built a three foot square copper loop with an insulator where it was mounted on a cast aluminum electrical box, and wound 20 turns of wire inside the 3/4" copper pipe after it was soldered together. I used an op amp to give some gain,. and I could watch the modulation. The big problem was a neighbor about a half mile away left a TV set on 24/7 and the horizontal oscillator drifted after the station went off, and the harmonics would drift right through 60 KHz. I wanted to use it for a frequency standard, but I couldn't do it there. I will try it again, some day, now that I have a couple miles of woods between me and Colorado. I have enough gain to get around 12V P-P at the power inserter. I used 75 ohm cable and "F" fittings because they were handy, but I would use Mini Circuits MMICs and 50 Ohm cable if I built another outdoor 60 KHz antenna. -- We now return you to our normally scheduled programming. Take a look at this little cutie! ;-) http://home.earthlink.net/~mike.terrell/photos.html Michael A. Terrell Central Florida I have no problem receiving it on a number of different Ham and General Coverage receivers using random wires or simple vertical whips. I also hear it well with an active antenna. I have not noticed any real QRM problems on 60kHz although there are some really strong noise sources at other frequencies nearby. Dave 45N 75W |
#6
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Steve and group:
I tuned my IC706 down there, and apparently the front end filters block anything that low. My Kenwood R-5000 hears the signal fine with a 100' random wire. The radio I would really like to try, the RCA AR-88LF, only goes down to 74 KHz, and I sold the old RAK? RAL? Navy monster which covers that range, so I have to believe the R-5000 on this one. The signal is a little weak mid-day, but strong the remainder of the time. I bought one of the cheap "atomic" wris****ches last month, and have been experimenting with orientation for sync. It has an indicator which shows if it has locked up in the last 24 hours, and the manual says it tries at 3 AM in whatever time zone it is set to. The wall clocks also have a lock indicator, and their manual says they try several times in the wee hours if the first try doesn't result in synchronization. But BEWARE, I have now observed two different instances, once each with two different clocks, that while indicating that resynchronization had occurred the previous evening, the clock indicated the time which was exactly 1 minute off, apparently due to a thunderstorm during the night. The orientation where the wris****ch synchronizes reliably is face down, BTW. -- Crazy George Remove N O and S P A M imbedded in return address |
#7
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![]() Chris Campbell wrote: I'm trying to get a radio clock to sync up with WWVB (60 kHz out of Colorado). ... From experience there are also differences in the performance of WWVB clock receivers of the same brand and model from opening the box and later from differences in aging. Several years ago I ordered a wris****ch and two travel clocks from one of then and still prominent "atomic" clock outfits. One of the travel clocks locked up soon (overnight? - brain cells fade) and the second shortly afterwards. The wris****ch just would not lock up - very small antenna, so I wasn't surprised that it would take longer. I tried leaving it overnight in parts of the away from PC, TV, radio, ... and orienting it in various ways to point it to Colorado. After about two weeks, when I had given up and was ready and call the company, I went on a trip from northern NJ to California. Somewhere, sometime during the trip it locked up. Then after returning home... nothing. Making a very long story short, the company _finally_ sent me a replacement wris****ch. The new one locked up nearly every night for the next 2 years and then, after any guarantee was gone, it quit. It still runs, just has long since drifted off time. Nothing since in the last 3 years, despite the deal of trying to find a 60-kHz quiet place, reorienting it... In the meantime, the travel clocks were doing fine, no matter where they were left or what part of the country I was in. Then about 2 years ago, one of them quit. Again - try finding that sweet, magic spot, leaving it side by side with its brother, oriented in the same direction. Always the same result - one fine, one deaf. I have thought about building a loop antenna like as has been disussed here to see if I could get at least the deaf travel clock locking. Tek makes tunable AM Loop antennas where the AM radio sits next to the loop and they do work out here in rural New Jersey. This discussion may yet spur me to physical wire and solder, not just typing, action. Somewhere I did have the URL of web page where a fellow built a shielded loop with an amplifier and all. The passive design, using Reg's program as a start, is simpler. I have several of the Sam's Club US$23 atomic wall clocks that lock up just fine, mounted on walls facing every which way. The outside temperature reading 433MHz receiver seems to be a flaky, marginal design, but that's a different story. Cheers, 73 Ron McConnell N 40º 46' 57.9" W 74º 41' 21.9" FN20ps77GV75 per w2iol or FN20ps77GU46 per K2RIW http://home.earthlink.net/~rcmcc |
#8
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Ron McConnell wrote:
I have thought about building a loop antenna like as has been disussed here to see if I could get at least the deaf travel clock locking. Tek makes tunable AM Loop antennas where the AM radio sits next to the loop and they do work out here in rural New Jersey. This discussion may yet spur me to physical wire and solder, not just typing, action. Somewhere I did have the URL of web page where a fellow built a shielded loop with an amplifier and all. The passive design, using Reg's program as a start, is simpler. I have several of the Sam's Club US$23 atomic wall clocks that lock up just fine, mounted on walls facing every which way. The outside temperature reading 433MHz receiver seems to be a flaky, marginal design, but that's a different story. Cheers, 73 Ron McConnell I built a Sheilded, amplified loop for my tests, and got a decent signal a few miles north of Orlando, years before they built the new towers, and transmitter. As far as the oudoor thermometer, Some cordless phones on the same band search for an open frequency, and wipe out the sync between the sensor and the clock. I need a cordless phone, more than the outdoor temperature, so I don't worry about it. -- We now return you to our normally scheduled programming. Michael A. Terrell Central Florida |
#9
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![]() Michael A. Terrell wrote: Ron McConnell wrote: I have several of the Sam's Club US$23 atomic wall clocks that lock up just fine, mounted on walls facing every which way. The outside temperature reading 433MHz receiver seems to be a flaky, marginal design, As far as the oudoor thermometer, Some cordless phones on the same band search for an open frequency, and wipe out the sync between the sensor and the clock. I need a cordless phone, more than the outdoor temperature, so I don't worry about it. My cordless phones work on 2.4GHz and the remote thermometers are on 433MHz - a frequency which is shared among many types of gadgets. I should add that there seemed to have been a redesign of the Sam's Club clock about a year ago. The remote temperature receiver seems better in new ones. I have 3 different brands of atomic-clocks-with-remote-thermometers working from one remote Sam's Club remote thermometer transmitter. Back to ham antennas... ![]() Cheers, 73 Ron McConnell N 40º 46' 57.9" W 74º 41' 21.9" FN20ps77GV75 per w2iol FN20ps77GU46 per K2RIW Magnetic declination 13ºW in early 2004 http://home.earthlink.net/~rcmcc |
#10
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Chris Campbell wrote:
"I am trying to get a radio clock to sync up with WWVB (60 KHz out of Colorado). A course in antennas is nice but loop antennas are covered in the "ARRL Antenna Book". In my 19th edition, loop antennas are covered starting on pages 5-1 and 14-2. See Fig 3 on page 14-3. At 60 KHz, any practical loop is physically small in terms of wavelength. The far field pattern of a small circular loop is the same as that of a small square loop of the same enclosed area (Kraus edition 3, page 197). Area equals the square`s side length squared, and that is equal to pi times the radius squared for the circular loop. Current is all in the same direction in the small loop, so there`s a null perpendicular to the plane of the loop and radiation is in the plane of the loop. If the loop is placed in the vertical position, radiation is vertically polarized as required for all ground wave propagation. Far field strength associated with a small loop is directly proportional to the enclosed area in terms of wavelength (Formula 8 on page 199 of Kraus). Every receiving antenna is also a transmitting antenna. The most power that may be tapped from the antenna is 50%, and a matched load is required to extract 50%. Any mismatch increases the % of re-radiation. At a 100% mismatch, i.e., a shorted dipole or an untapped resonant loop, 100% of the energy captured must be re-radiated. So, set up a large resonant loop to capture all the 60 KHz energy you can. Position the 60 KHz receiver (clock) to couple the most desired energy and the least undesired energy possible into the receiver. A high-Q loop, except for radiation resistance, is desirable. Litz` wire uses copper better than solid wire does at 60 KHz. Best regards, Richard Harrison, KB5WZI |
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