Time and Frequency References
How important are time and frequency references to amateur radio
operators? I've been working on a radio controlled clock design that would be capable of generating a 32.768 kHz, 60 kHz, 240 kHz, 1 MHz and 10 MHz frequency references in addition to providing the time and date. Initially it would be capable of receiving the 60 kHz transmissions of WWVB and MSF. With minor tweaks other stations could be received. Would this be useful to others? -- Rick |
Time and Frequency References
In article , rickman
wrote: How important are time and frequency references to amateur radio operators? I've been working on a radio controlled clock design that would be capable of generating a 32.768 kHz, 60 kHz, 240 kHz, 1 MHz and 10 MHz frequency references in addition to providing the time and date. Initially it would be capable of receiving the 60 kHz transmissions of WWVB and MSF. With minor tweaks other stations could be received. Would this be useful to others? Rick- Anyone who would use your frequency reference might be interested if it is less expensive than other methods. I believe GPS-trained references are available. I have a rubidium-controlled oscillator I bought on E-Bay. For routine Ham Radio use, I depend on 20 MHz WWV to periodically check the calibration of my transceivers. By switching between CW and CW-R, I can adjust the equipment so the CW pitch is the same for both. I am confident that I can adjust a radio so it is within one Hz at 20 MHz. That puts me within 0.05 parts per million, at least at the moment I make the adjustment. I expect the equipment to drift over time and temperature. Most Amateur Radio Operators do not worry that much about frequency. Some of the people I talk to on higher frequencies, drift over a few minutes time. Nobody seems to care! Fred K4DII |
Time and Frequency References
On 18/04/2016 15:39, rickman wrote:
How important are time and frequency references to amateur radio operators? I've been working on a radio controlled clock design that would be capable of generating a 32.768 kHz, 60 kHz, 240 kHz, 1 MHz and 10 MHz frequency references in addition to providing the time and date. Initially it would be capable of receiving the 60 kHz transmissions of WWVB and MSF. With minor tweaks other stations could be received. Would this be useful to others? A good frequency standard has many uses for the radio amateur. There are many designs around many using GPS as the reference source as well as MSF and the like. -- Peter Crosland Reply address is valid |
Time and Frequency References
On 18/04/16 15:39, rickman wrote:
How important are time and frequency references to amateur radio operators? I've been working on a radio controlled clock design that would be capable of generating a 32.768 kHz, 60 kHz, 240 kHz, 1 MHz and 10 MHz frequency references in addition to providing the time and date. Initially it would be capable of receiving the 60 kHz transmissions of WWVB and MSF. With minor tweaks other stations could be received. Would this be useful to others? Anyone who wants high accuracy off air time and frequency standards would use GPS these days. Even that is almost two decade old technology in amateur radio usage: http://www.tapr.org/kits_tac2.html Also note that cross-posting to a moderated newsgroup will delay the posting in the unmoderated group and cross-posting to two moderated groups will, almost certainly, stop it being distributed at all. |
Time and Frequency References
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Time and Frequency References
On 4/18/2016 5:43 PM, David Woolley wrote:
On 18/04/16 15:39, rickman wrote: How important are time and frequency references to amateur radio operators? I've been working on a radio controlled clock design that would be capable of generating a 32.768 kHz, 60 kHz, 240 kHz, 1 MHz and 10 MHz frequency references in addition to providing the time and date. Initially it would be capable of receiving the 60 kHz transmissions of WWVB and MSF. With minor tweaks other stations could be received. Would this be useful to others? Anyone who wants high accuracy off air time and frequency standards would use GPS these days. Even that is almost two decade old technology in amateur radio usage: http://www.tapr.org/kits_tac2.html Is there something about GPS that is inherently superior for a frequency reference? For setting a time, GPS can provide a smaller offset, but I don't see where it has any advantages over WWVB or similar station broadcasts where you can receive them. The main limitation of a GPS receiver is the need for an outside antenna for many installations. A WWVB receiver is self contained and much lower cost. -- Rick |
Time and Frequency References
In article rickman writes:
On 4/18/2016 5:43 PM, David Woolley wrote: On 18/04/16 15:39, rickman wrote: How important are time and frequency references to amateur radio operators? I've been working on a radio controlled clock design that would be capable of generating a 32.768 kHz, 60 kHz, 240 kHz, 1 MHz and 10 MHz frequency references in addition to providing the time and date. Initially it would be capable of receiving the 60 kHz transmissions of WWVB and MSF. With minor tweaks other stations could be received. Would this be useful to others? Anyone who wants high accuracy off air time and frequency standards would use GPS these days. Even that is almost two decade old technology in amateur radio usage: http://www.tapr.org/kits_tac2.html Is there something about GPS that is inherently superior for a frequency reference? For setting a time, GPS can provide a smaller offset, but I don't see where it has any advantages over WWVB or similar station broadcasts where you can receive them. The main limitation of a GPS receiver is the need for an outside antenna for many installations. A WWVB receiver is self contained and much lower cost. GPS allows accurate locking to frequency, WWVB no longer does, since they use phase modulation on the WWVB signal. The "low cost" WWVB receivers never could do that, they are only able to be used for clock setting, not accurate frequency determination. The WWVB signals are much more affected by the ionosphere, as daytime absorbtion can make the signal unusable to small receve antennas. Also, WWVB does need an antenna for good performance, especially compared to small indoor antennas. WWVB suffers from occasional interference on the east coast from MSF. Alan |
Time and Frequency References
rickman wrote:
On 4/18/2016 5:43 PM, David Woolley wrote: On 18/04/16 15:39, rickman wrote: How important are time and frequency references to amateur radio operators? I've been working on a radio controlled clock design that would be capable of generating a 32.768 kHz, 60 kHz, 240 kHz, 1 MHz and 10 MHz frequency references in addition to providing the time and date. Initially it would be capable of receiving the 60 kHz transmissions of WWVB and MSF. With minor tweaks other stations could be received. Would this be useful to others? Anyone who wants high accuracy off air time and frequency standards would use GPS these days. Even that is almost two decade old technology in amateur radio usage: http://www.tapr.org/kits_tac2.html Is there something about GPS that is inherently superior for a frequency reference? For setting a time, GPS can provide a smaller offset, but I don't see where it has any advantages over WWVB or similar station broadcasts where you can receive them. The direct-sight UHF radio link provides less jitter and uncertainty than the VLF signal that suffers from propagation effects. The main limitation of a GPS receiver is the need for an outside antenna for many installations. A WWVB receiver is self contained and much lower cost. Sure it can be easier to place an antenna for a VLF station, but on the other hand there is much more interference, mainly from switchmode powersupplies these days (in the old days it was from CRT computer monitors), but also from lightning. |
Time and Frequency References
On 4/20/2016 12:01 PM, Rob wrote:
rickman wrote: On 4/18/2016 5:43 PM, David Woolley wrote: On 18/04/16 15:39, rickman wrote: How important are time and frequency references to amateur radio operators? I've been working on a radio controlled clock design that would be capable of generating a 32.768 kHz, 60 kHz, 240 kHz, 1 MHz and 10 MHz frequency references in addition to providing the time and date. Initially it would be capable of receiving the 60 kHz transmissions of WWVB and MSF. With minor tweaks other stations could be received. Would this be useful to others? Anyone who wants high accuracy off air time and frequency standards would use GPS these days. Even that is almost two decade old technology in amateur radio usage: http://www.tapr.org/kits_tac2.html Is there something about GPS that is inherently superior for a frequency reference? For setting a time, GPS can provide a smaller offset, but I don't see where it has any advantages over WWVB or similar station broadcasts where you can receive them. The direct-sight UHF radio link provides less jitter and uncertainty than the VLF signal that suffers from propagation effects. That is important if you are looking for microsecond timing. But it has very little impact on use as a frequency reference. The main limitation of a GPS receiver is the need for an outside antenna for many installations. A WWVB receiver is self contained and much lower cost. Sure it can be easier to place an antenna for a VLF station, but on the other hand there is much more interference, mainly from switchmode powersupplies these days (in the old days it was from CRT computer monitors), but also from lightning. I guess you aren't familiar with the extremely narrow band timing signals, 1 bps. I'm working on a receiver with a 30 Hz bandwidth to exclude environmental noise. -- Rick |
Time and Frequency References
rickman wrote:
On 4/20/2016 12:01 PM, Rob wrote: rickman wrote: On 4/18/2016 5:43 PM, David Woolley wrote: On 18/04/16 15:39, rickman wrote: How important are time and frequency references to amateur radio operators? I've been working on a radio controlled clock design that would be capable of generating a 32.768 kHz, 60 kHz, 240 kHz, 1 MHz and 10 MHz frequency references in addition to providing the time and date. Initially it would be capable of receiving the 60 kHz transmissions of WWVB and MSF. With minor tweaks other stations could be received. Would this be useful to others? Anyone who wants high accuracy off air time and frequency standards would use GPS these days. Even that is almost two decade old technology in amateur radio usage: http://www.tapr.org/kits_tac2.html Is there something about GPS that is inherently superior for a frequency reference? For setting a time, GPS can provide a smaller offset, but I don't see where it has any advantages over WWVB or similar station broadcasts where you can receive them. The direct-sight UHF radio link provides less jitter and uncertainty than the VLF signal that suffers from propagation effects. That is important if you are looking for microsecond timing. But it has very little impact on use as a frequency reference. It depends on the stability of your oscillator and the integration time that you can use as a result of that. Short-term frequency accuracy is not much different from accurate timing. The main limitation of a GPS receiver is the need for an outside antenna for many installations. A WWVB receiver is self contained and much lower cost. Sure it can be easier to place an antenna for a VLF station, but on the other hand there is much more interference, mainly from switchmode powersupplies these days (in the old days it was from CRT computer monitors), but also from lightning. I guess you aren't familiar with the extremely narrow band timing signals, 1 bps. I'm working on a receiver with a 30 Hz bandwidth to exclude environmental noise. I have experience with receivers for DCF77, which is a similar station to MSF and WWVB. The frequency is 77.5 kHz. Of course the results depend on the quality of the receiver. I use some receiver modules from "atomic clocks" but I also have a somewhat better receiver which has a crystal lattice filter. I need to find a good spot for the antenna, away from certain equipment, for it to work well. E.g. I had a problem with a switchmode powersupply I used for the station in the past, which is switching at around 25 kHz. The third harmonic (which of course drifts around depending on load and temperature) interfered with the DCF77 receiver when it is within about 3 meters. I now have a different supply and this problem is gone, but of course that is just coincidence. Older CRT monitors for computers also emit quite a strong field in this frequency range. Fortunately the frequency is quite stable, so it is either OK or it is a problem, and it could be solved by changing the display parameters. Finally, when there are thunderstorms around, the signal often becomes undetectable due to the many interference bursts. |
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