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If you can help us with additions, corrections, new links, please contact
us.
The address is on the NZ&A Time home page.
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Short Wave radio - traditionally our
timing "workhorse"
Short Wave Radio Standard Time signals have long been a favourite tool for
scientific workers and observers at field sites, where medium accuracy time
is needed, to be recorded continuously. At times of good radio propagation,
any simple radio with a SW band can be used to pick up a usable signal.
In addition to time pips, the SW signal usually also gives voice or coded
time (Hour and Minute) information and station ID. The most suitable
source of standard time signals in the South Pacific is WWVH, broadcasting
from Hawaii.
An interesting note on the 'as received' accuracy
of time signals, far away from their transmitter site, can be found in this
archived post by Art Lucas
on the IOTA Occultations email group at: http://groups.yahoo.com/group/IOTAoccultations/
In practice, the WWVH signal from Hawaii can be used for (visual, manual)
basic timing tasks as far away as Australia with a propagation delay of the
order of 0.05 second (approx. 50 ms).
| Also see the note below on a local group in New Zealand with interest in time on HF |
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VNG (Australia) died on 31 December 2002 at 23:43:43 UTC Standard time signals were available until 31 December 2002 in Australia through VNG on 2.500, 5.000, 8.638, 12.984 or 16.000 MHz (daytime only) short wave. A full description of the Station, its history and details of broadcast codes and format can be found in National Standards Commission information leaflet "Radio VNG".) If you would like to hear the last minute of VNG transmission on 12.984 MHz, please check this MP3 sound file. The last second marker was at 23:43:43 UTC |
When VNG was still available, the receiving equipment could be any cheap old analogue (second hand shop) battery operated portable. Since the closure of VNG on 31 December 2002, the SW time signals available in the South Pacific have to travel from Hawaii, mainland USA, Canada or China. The received signal strength in New Zealand and Australia is lower and more variable than that from VNG, making reliable reception more difficult. In good conditions, however, the WWVH signal strength can still be remarkably good for a few hours. To improve the performance of your receiver, it is worth experimenting with long and short extension aerials. Try different antenna compass orientations, and stay away from power and cable TV cables and electric fences, all known sources of noise and interference. Short Wave radio can still be a useful, adequate, low cost entry point into fairly respectable timing.
There is an excellent up-to-date Time Signal Stations Frequency List by Klaus Betke. Also refer to David Mills' excellent site Information on Time and Frequency Services
WWVH (Hawaii) and WWV (Colorado)
WWVH and WWV broadcast on the international time standard frequencies of
2.5, 5, 10, 15 and 20 (WWV only) MHz. In New
Zealand and Australia 5 and 10 are the best at night, 10 and 15 (on rare
occasions also 20 MHz) in the daytime and early evening. Mostly, WWVH
is received at the best signal strength, with WWV faintly in the background,
but at times WWV is almost as good.
(Currently, in 2002 - 2002, there is a severe interference problem in Western Australia with many Indonesian fishing vessels using 10 MHz as their communication channel, ignoring international regulations. This "chatter" is noticeable as far as South Eastern Australia, but WWVH is mostly still "usable" there.)
On WWVH and WWV the seconds pulses are heard every second except on the 29th and 59th seconds of each minute. The first pulse of each hour is a long 800 ms pulse of 1500 Hz. The first pulse of each minute is a long 800 ms pulse of 1000 Hz at WWV and 1200 Hz at WWVH. The remaining seconds pulses are very short audio bursts (5 ms pulses of 1000 Hz at WWV and 1200 Hz at WWVH) that sound like the 'ticking' of a clock
The voice time announcements (female for WWVH, male for WWV) are just before
each minute, and space and earth weather information is broadcast at set
times. For timekeeping ignore the ongoing continuous tones on WWV/WWVH
which are often heard from second 1 (i.e. the tones start one second after
the full minute) until second 45. The complete format descriptions
of the WWVH and WWV time codes can be found at the NIST web site: http://www.boulder.nist.gov/timefreq/
| Can you hear confusing 'double' or 'twin'
second markers ? Do these occur during the minutes 25 - 29 and 55 - 59 ? For example, on WWVH, do you hear: - - - - - tick pip - - - - - tick pip - - - - - tick pip - - ? This is caused by the Chinese BPM ‘UT1’ time pips - Check This Because the signals from WWVH and WWV are often weak, there is a likelihood of interference from other standard time stations on the same international frequencies of 5, 10 and 15 MHz. Most of these are no problem, because they also transmit UTC and are usually much weaker. One of these is standard time station ‘BPM’ in Pucheng, China, which is operated by the Chinese National Time Service Center (NTSC) (Shaanxi Astronomical Observatory, Chinese Academy of Sciences). Like other standard time signal stations, most of the time BPM transmits UTC. However, during the minutes 25 - 29 and 55 - 59, station BPM transmits UT1. Ref: Time Signal Stations Frequency List by Klaus Betke. This is a complex issue, because the difference (DUT1) between UT and UT1 can be positive or negative, and can be up to 0.9 sec. As a result, the BPM UT1 'pips' can be before or after the WWVH UTC 'tics'. If you encounter this problem with these two stations, then luckily they can be separated because the WWVH and WWVH second markers are 'ticks', and the BPM pips are 'beeps'. At present (July 2002) DUT1 is 0.2 seconds. Check this NIST web site for up to date information: http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm The identity of station BPM can be confirmed by listening during
the last minute of the hour, just before the full hour, when a female (Chinese)
voice speaks the words: "B P M ,..... B P M ,..... B P M ,.....".
And, to confirm this further, the 'double' pips should disappear on the half
or full hour. Repeat: this paragraph only applies to the UT1 pulses
during minutes 25 - 29 and 55 - 59. |
CHU (Ottawa, Canada)
At times, on the 'non-standard' frequencies of 3.300, 7.335 and 14.670 MHz,
Canadian Standard Time Signal Station 'CHU' can also be received for a few
hours in the South Pacific. The 29th and 51st to 59th Second Markers
are omitted, and alternating bilingual voice announcements of local time
(not UTC) are made between seconds 50 and 59. There are further complex
time codes built into this signal between seconds 31 and 90 - for details
see the Klaus Betke site. However, we find that: if CHU is present,
WWVH or WWV are most likely stronger, and preferred for their easier to read
time code system. Also, importantly, Hawaii (the source of WWVH) is
much closer to New Zealand and Australia than Ottawa, so that there is less
propagation delay.
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INTEREST IN HF TIME DISTRIBUTION IN NEW ZEALAND An amateur radio group in New Zealand has access to very respectable time generating and low power HF transmitting equipment. More details on the we site http://www.qsl.net/zl1bpu/micro which is maintained by Murray Greenman ZL1BPU
Please contact Murray directly for technical enquiries, expressions of interest
and offers of support. |
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For Domestic FM / AM radio stations in New Zealand
and Australia:
Please follow this link to the Broadcast
Page
Do not use time pips on International SW broadcast
stations (e.g. the BBC)
Do not rely on time signals on large International SW broadcast stations (e.g.
the BBC, RN, DW), which broadcast time pips on the full hour. The problem
is that these SW (HF) broadcast programmes are distributed around the world
using extremely long paths and variable networks that often include satellite
links which add very large delays. As received, they can be significantly
delayed. An exception is Radio New Zealand International
(RNZI), as this only has one local transmitter. The signal from RNZI is therefore
similar to that from the regular NZ
National Radio - please refer to the notes there.
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