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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 |
#5
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Dave Holford wrote:
"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 Look at the design of the front end. If it is capacitor coupled, the capacitive reactance is so high that it blocks anything below 200 KHz. In this case you can add another cap in parallel to improve the lower frequencies. Multiply the original by 100 or higher, and add it in parallel to reduce the capacitive reactance, and the attenuation. I built a broadband DC block for my bench at Microdyne that had five caps in parallel. It was flat to less that a half dB from 50 KHz to 450 MHz, and had a VSWR of less than 1.05 across the entire range. It was built to maintain a 50 ohm impedance end to end. If it has a transformer, the losses are too high at low frequencies. In that case I would build a low pass filter and pre amp, and couple it to the input of the mixer to see how it performs. You would have to shut it off to use other bands, though. 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 They only signals I saw were WWVB, and that damned TV's harmonics drifting through 60 KHz after the station went off the air. The guy was only there a couple days a month, and left the TV on to make people think he was home. -- We now return you to our normally scheduled programming. Michael A. Terrell Central Florida |
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