The ZL1VHF 6m beacon was originally commissioned some time back in the 1970s, on the original
frequency of 51.020 MHz, and transmitted its ID using both CW keying and FSK modulation, and was widely heard
around the Pacific area.
The beacon operated until sometime during the early 1990s, when an antenna failure meant that transmissions
had to be temporarily ceased, so that the antenna could be either repaired, or replaced.
The beacon was then operating from a site called Nihotupu, a point on the Waitakere ranges, to the
west of Auckland city, near the city's television and then FM radio transmitter site.
Still operating from this site is the 2m (144.240 MHz) and 70 cm (432.240 MHz) beacons, and the
ZL1BQ TV repeater, on UHF channel 39 (615.25/620.75 MHz).
Back at some stage during 1999, I was talking to another group of 6m operators back in Christchurch
and the subject soon turned to beacons, and how it would be good if we had an operational 6m beacon
here in Auckland, so the idea of re-commissioning ZL1VHF on 6m was born.
We set about to find what would be an appropriate frequency for use in this part of the world, and
we searched through worldwide beacon lists, to find a suitable frequency (or frequencies) for a beacon
in this part of the Pacific rim area.
We had identified 3 possibilities in the international beacon segment, so it was taken to a meeting
of our club, the Auckland VHF Group Inc, and proposed, with no objections. Step 1 complete,
now for the paper trail to begin, and our application for a new beacon was submitted, and accepted
Our first choice frequency did not seem to pose a problem.
A crystal was then ordered for the transmitter previously used for the original beacon, to bring it
onto the new frequency, and when it arrived, the transmitter exciter was duly tuned up, and tested.
All seemed OK, and the PA stage was then brought down from the original site, set up and tested.
The beacon transmitter was operated on test at the QTH of Quentin, ZL1QF, and ran for a couple of weeks
into a dummy load, where it operated without a hitch, producing a steady 10 watts output.
During mid November 2000, I had the beacon operating from my QTH, beaming south using my yagi antenna
for the duration of the Leonids meteor shower, as an experiment between Auckland and Christchurch
to look at the propagation that results from meteor reflections.
The ZL1VHF beacon was heard several times by some of the operators in Christchurch, as well as one operator
in Greymouth, on the South Island's west coast, at quite good strength at times.
After a couple of weeks of operation from my place, it was turned off, and moved out to it's new
location at Whitford, where it is sited at an elevated location, away from any houses, and where it is not
accessible to the public.
The Whitford site is home to the new TV repeater, transmitting on 1248 MHz FM, and receiving on
1284 MHz FM, and also UHF channel 39. A channel 7 PRS repeater (476 MHz) is co sited also,
and now the ZL1VHF beacon on 6m.
The Whitford site is located approximately 30km south east of the Auckland city CBD, in grid square
RF73MB, and the station hut is at a height of 230m, with excellent views over about 270 degrees, from
south west round through north, to the south east, at the horizon. There is an excellent view
over the Hauraki Gulf, to the city's north and east, and to the west, the Auckland International
airport, and the heads of the Manukau harbour.
ZL1VHF was finally back on the air early in December 2000, after some extensive retuning if its antenna
and fine tuning everything. The antenna was previously resonating nicely around 53 MHz, not 50 MHz
where we needed it to operate.
I first heard it on air from the new site during the annual VHF and up field day site, from our favourite
spot at Maunganui Bluff (RF64SG), some 260km by road from Auckland.
Over the next few months we noticed that there was a noticeable drift in frequency from the nominal
50.043 MHz, by up to around 2 kHz, which followed a regular pattern from one day to the next.
It soon became apparent that early in the morning, the beacon's frequency was around 50.0415, as the sun
rose, and the temperature increased at the site, the frequency would drift up, settling around
50.0435 MHz at the warmest part of the day, and then back down during the evening.
Several things were tried, from improving power supply regualation, to attempts at insulating the oscillator
from temperature changes, but to no avail, the drift continued.
A different fault, this time in the keyer, occured during late January, holding the beacon in constant
key down transmit state, however this fault disappeared later that evening, and the beacon operated normally
for the next few weeks, before returning permanantly.
Around this time, a new transmitter was obtained from Tait Electronics Ltd in Christchurch,
tuned up on 50.0433 MHz, as close as it could be to our nominal 50.043 MHz allocation.
The new transmitter is a Tait T-826 transmitter, originally designed as a base station FM repeater
transmitter to operate in the 68 - 88 MHz band, but retuned and reconfigured for use as a 50MHz
beacon, using on-off CW keying. Although the transmitter has a rise time from zero to full power of
about 20ms, it is not noticeable to the ear when heard on an SSB receiver.
With the new Tait transmitter, there is also a new keyer, which was built by Ian, ZL1VFO, using an EPROM
to store the transmitted ID string.
The new Tait transmitter and keyer were installed and commissioned on February 21, 2001.
The configuration currently in use is, a half wave vertical antenna, about 4m above the ground,
fed by around 8m of RG-213 coax, to the transmitter, which is now running a steady 20 Watts output.
The transmitted ID is "ZL1VHF WHITFORD RF73MB ZL1VHF" followed by 10 seconds of interrupted carrier
which is carrier on for 15/16th of a second, and off for 1/16th of a second.
In the time that ZL1VHF on 6m has been on the air, it has been widely heard, all over eastern Australia
almost every day during the last summer, in Japan, around many parts of the USA, Alaska, the Carribean
and as far away as Spain, and Romania, during April 2001.
I have a recording of the ZL1VHF 6m beacon, as heard by Jose, EH7KW, in Southern Spain, a day or so after I
had a successful 2 way contact to EH7KW, the same day that it was heard in Romania.
ZL1VHF has also been frequently heard by ZL3TIC in Christchurch, nearly always at very high signal
strengths.
I was lucky enough to hear the beacon appear out of the noise from the QTH of Trevor, VK4AFL,
during a recent visit to Brisbane, Australia. Quite unexpectedely, we were looking around, and found
there was quite strong New Zealand TV Channel 1 sound on 50.750 audible, and there, getting stronger,
out of the noise was our beacon, right bang on frequency. It peaked about S5 or so, but there were
no contacts back into Auckland, no response to our CQ calls. We heard it at similar levels about
6 hours later, but again, no response to CQs.
ZL1VHF has now been operating for about 6 months, about 3 1/2 months of that time on the new
Tait transmitter and the Ian, ZL1VFO special keyer, with no problems.
If you hear ZL1VHF, please send a report to ZL3VTV.