Chronology - most recent news first
[all transmssions on 136kHz unless stated otherwise]
20 December 2001: CLAIM OF ZL TO VE1 AMATEUR LF DX
On Saturday 15 December ZL6QH transmitted a low speed frequency
shift keyed test signal in the 136kHz band, as a beacon transmission
for all hours of local darkness. John VE1ZJ managed to receive and
positively identify signals from ZL6QH. The path length from ZL6QH
near Wellington to VE1ZJ in Sydney, Nova Scotia has been calculated
as being 15,645 km. VE1ZJ received the LF signal using a 10 metre
vertical with top loading, high impedance pre-amplifier, low pass
filter and a TS-850 receiver. The demodulated audio was fed to a computer
sound card for filtering and display of the signal using Argo software.
Weak signals were first received by VE1ZJ at 0845 UTC, which was some
40 minutes after ZL sunset at 0806 UTC and some three hours before
VE1 sunrise at 1150 UTC. Best reception was from 1045 to 1138 UTC.
Previous best DX for ZL6QH was confirmed reception by Dexter W4DEX
two weeks earlier, over a distance of 13,633 km [see below].
W4DEX received ZL6QH again but generally not as well as the previous
time. In June and September ZL6QH was received by VE7SL, when the
test frequency was 184.4 kHz, but since then the ZL6QH signal has
not been received at all, despite operators being ready to try for
an LF/HF cross-band contact if propagation was satisfactory at the
time. The ZL6QH transmitted signal used frequency shift keying, with
0.4 Hz frequency shift. The uniquely coded transmission consisted
of repetitive sending of QQQQQ. sent as 137.7900, 137.7900, 137.7896,
137.7900 and then a gap, with all elements being of 120 seconds (2
minutes) duration. This means sending a single Q takes ten minutes.
The ZL6QH LF signal was generated using a modified TS-850SAT, in SSB
mode, fed with audio from a lap top PC, using soundcard software developed
by Steve VK2ZTO. TS-850 frequency control was by means of a high performance
TCXO master oscillator. The low level LF signal from the TS-850 transverter
port was fed to an external LF power amplifier, and the output power
was around 500 watts. The radiated power is estimated to be 4 watts.
The antenna was a long wire at the Quartz Hill club station, which
is run by the Wellington Amateur Radio Club. The ZL6QH operator was
Mike ZL4OL. The next test from ZL6QH in the 136 kHz band will likely
be in mid January.
Bob Vernall ZL2CA Organiser of the ZL LF DX tests
1 December 2001: ZL to W4 on 136kHz
ZL6QH smashed the world 136kHz distance record when
he transmitted the letter Q repeatedly in QRSS with a dot speed of
120 seconds. W4DEX in North Carolina received several Qs, using Argo
software, at a distance of 13,633km. W1TAG received a fragment but
not enough to confirm reception. The previous record for 136kHz was
M0BMU to W4DEX set last winter at 6380km.
Operator Bob Vernall, ZL2CA, says: "all went well at ZL6QH
from a transmission point of view, for all New Zealand hours of darkness.
I had a brief outage for 10 minutes, from 0730 UTC, but that was before
sunset last evening. I went QRT at 1600 UTC, an hour after local sunrise.
....... I also consider my TCXO master oscillator controlled LF frequencies
held within 0.1 Hz of declared. I had a two-way QSO on 40 metres with
Steve VE7SL, but he got nil on LF, so ZL6QH did not depart from the
120 second dot length all night."
VE7SL was previously the only North American station to receive a
transpacific LF station (see below).
The picture is one of three posted by W4DEX. The dashes of the letter
Q (with no space between them) are clearly visible at +0.1Hz of nominal,
and the dots some 0.4Hz lower.
Several UK stations monitored but did not copy anything. ZL6QH will
be having another all night transmission on 15 December.
Bob, ZL2CA summarised the event as follows:
CLAIM OF ZL TO W4 AMATEUR LF DX 4 December 2001
On Saturday 1 December ZL6QH sited near Wellington, New Zealand transmitted
a low speed frequency shift keyed test signal in the 136 kHz band.
This was the first time that DX testing in he 136 kHz band has been
tried by ZL6QH, since having the 135.7 - 137.8 kHz band recently added
to the club station Low Frequency Permit. Various DX listeners had
prior knowledge of the ZL6QH test transmission, which ran for all
hours of local darkness. Dexter W4DEX managed to receive and positively
identify signals from ZL6QH. The path length from ZL6QH to W4DEX in
North Carolina has been calculated as 13,633 km. W4DEX used receiving
equipment with the audio fed to a computer sound card for filtering
and display of the signal.
This is now a popular technique used for "below the noise" detection
of amateur LF signals, as ZL6QH was using 120 second dot length (each
transmitted bit was 2 minutes) and there can be nil detected by ear,
yet coding of the wanted signal can be seen after DSP filtering and
displaying on the screen. The screen display can be captured and saved
as a file, as a record of what was received, and for passing to others
by electronic means. Best reception was reported as being between
about 0904 and 0950 UTC, which is approximately one to two hours after
ZL6QH sunset at 0800 UTC and about two to three hours before W4DEX
sunrise at 1212 UTC. The radio equipment used by W4DEX was a square
loop antenna, 2.3 metres per side, balanced pre-amplifier feeding
an HP3586B selective level meter. The ZL6QH transmitted signal used
dual frequency keying, with 0.4 Hz frequency shift. The uniquely coded
transmission consisted of repetitive sending of QQQQQ. sent as 137.7900,
137.7900, 137.7896, 137.7900 and then a gap, with all elements being
of 120 seconds (2 minutes) duration. This means sending a single Q
takes ten minutes. The timing was such that the start of a fresh Q
was on the hour, so coding by absolute timing was another factor that
could be used for analysis of weak signal detection. The ZL6QH LF
signal was generated using a modified TS-850SAT, in SSB mode, fed
with audio from a lap top PC, using soundcard software developed by
Steve VK2ZTO. TS-850 frequency control was by means of a high performance
TCXO master oscillator. The low level LF signal from the TS-850 transverter
port was fed to an external LF power amplifier, and the output power
was around 500 watts. The radiated power is estimated to be 4 watts.
The antenna was a long wire at the Quartz Hill club station, which
is run by the Wellington Amateur Radio Club. The ZL6QH operator was
Bob ZL2CA. The next test from ZL6QH in the 136 kHz band will be on
15 December.
Bob Vernall ZL2CA Organiser of the ZL LF DX tests
26 September 2001: A SECOND CLAIM OF ZL TO
VE AMATEUR LF DX - From ZL2CA
On Saturday 22 September ZL6QH, ZL3PN, ZL3JE, ZL4OL and AX2TAR (VK7ZAL)
transmitted test signals in the 165 - 190 kHz band, for so-called
trans-Pacific tests. Various DX listeners had prior knowledge of the
schedule of individual test frequency and coding used by each station.
As occurred in the 30 June trans-Pacific tests, Steve
VE7SL managed to receive signals from ZL6QH before VE7 dawn. This
time VE7SL obtained an Argo capture of both frequencies of the DFCW
transmission. The path length is estimated to be 11,709 km.
Refer to the associated Argo graphic. The ZL6QH signal
is in the lower half of the screen. The transmitted signal used dual
frequency keying, with 0.4 Hz frequency shift. The uniquely coded
transmission consisted of repetitive sending of QQQQQ… sent as
184.4001, 184.4001, 184.3997, 184.4001 kHz and then a gap, with all
elements being of 120 seconds (2 minutes) duration. This means sending
a single Q took ten minutes.
The Argo graphic of the VE7SL reception shows inverted
audio FSK , but otherwise agrees with the dot length, sequence and
frequency shift of the ZL6QH transmission. The explanation for the
inversion is that the Icom IC-R75 receiver used by VE7SL happens to
give inverted FSK in the audio output when used in the normal CW mode.
VE7SL used an RF signal generator to subsequently verify that an Argo
trace (showing receiver audio output) went lower in frequency when
the RF frequency went higher. Note that the parallel vertical red
lines in the centre of the Argo graphic are a software option for
selecting either short or long "ticks" and once selected,
a tick stays on the screen. The left side of the long tick is close
to 40 minutes before the 1401 UTC sunrise at VE7SL. The signal faded
rapidly about 3 minutes after sunrise. It was still dark in New Zealand
at VE7 sunrise.
The ZL6QH LF signal was generated using a modified
TS-850SAT, in SSB mode, fed with audio from a lap top PC, using soundcard
software developed by Steve VK2ZTO. TS-850 frequency control was by
means of a high performance TCXO master oscillator. The low level
LF signal from the TS-850 transverter port was fed to an external
LF power amplifier, and the output power was around 500 watts. The
radiated power is estimated to be 5 watts. The antenna was a long
wire at the Quartz Hill club station, which is run by the Wellington
Amateur Radio Club. The ZL6QH operators were Andrew ZL2BBJ and Bob
ZL2CA.
ZL6QH is seeking permission to transmit in the 136
kHz band, which could widen the scope of testing beyond "trans-Pacific",
and give European listeners a better chance at receiving amateur LF
DX from down-under.
Bob Vernall ZL2CA, Organiser of the Trans-Pacific
tests
21/22 September 2001: Tests were carried out
by AX2TAR Hobart, ZL3FJ Christchurch, ZL3PN Timaru, ZL3JE Pareora,
ZL4MD Cromwell, ZL6QH Wellington, ZL4OL Dunedin. Reception reports
should be e-mailed to vernall@xtra.co.nz
14 August 2001: ZL2CA reported "quite
good reception" of a 183 kHz carrier around ZL sunrise, presumably
the German broadcast station. A series of 3 Argo captures show some
deep fades, but at best "a very good solid line" using the
30 second dot setting.The carrier frequency was within 0.1 Hz of 183
kHz. According to ZL4OL the sunrise/sunset times for mid August mean
that the only dark path times for Germany to New Zealand are around
ZL sunrise, and then for only tens of minutes. The 183 carrier was
received for much longer than that, but did build up and then drop
out either side of the time for a dark path. Reception of 183 around
ZL sunset has been nil, not surprising for current sunrise in Germany.
ZL2CA commented that "There is perhaps a glimmer of hope for
amateur QRP signals to make it between EU and ZL", adding "The
ZL6QH trustee has made a request to the New Zealand licensing authority
for the European 136 kHz band to be added to the existing low frequency
permit."
9 August 2001: It was announced that on the
occasion of the equinox, ZL and VK LF stations would transmit QRSS
between 176 and 185kHz.
The chances of any European participation would be reduced by the
2MW French broadcast station, Europe 1 at Saarlouis, on 183.0 kHz..
M0BMU suggested that the quietest frequency in the 165 - 190kHz range
is some hundreds of Hz wide centred on about 172.0kHz.
Based on early experience with the transatlantic tests, G3NYK commented
that "if the boys in ZL can't hear the German commercial monster
Europe 1 on 183 kHz (2 megawatts erp) there doesn't seem much chance
we'll hear you. All the integration in the world isn't going to recover
63 dB (assuming it's a reciprocal path of course). Working to VE7/W7
it is different - the approximately north/south darkness path for
you means daylight in our half of the globe so Europe 1 shouldn't
propagate around to VE7 and jam you although it's only half as far
away. It has to go over the Polar Cap so add 20 db to the usual figures.
And vice-versa. Until you hear DBF39 you won't hear us on 136. And
even then we would have to make up about 37 dB. It might be a good
idea if somebody in ZL could organise an automated watch on DBF for
the next six months to see if anything is heard (seen?). Shouldn't
be too hard to do with Argo, Speclab, or similar."
5 July 2001: CLAIM OF ZL TO VE AMATEUR LF DX
On Saturday 30 June ZL1WB, ZL6QH, ZL3VN, ZL3FJ, ZL3PN, ZL3JE, ZL4OL
and AX2TAR (VK7ZAL) transmitted test signals in the 160 - 190 kHz
band, for so-called trans-Pacific tests. Steve VE7SL, located on Mayne
Island, some 40 km northwest of Victoria, British Columbia, managed
to capture some interesting signals using an Icom IC-R75 receiver
along with a PC with sound card, running Argo software. From an analysis
of the screen capture, it is claimed that VE7SL received and positively
identified signals from ZL6QH (operators were Andrew ZL2BBJ and Bob
ZL2CA). It is also very likely that signals were received from Mike
ZL4OL, but co-channel interference made the result too indistinct
to obtain positive identification of coding. The propagation opening
was around VE7 sunrise time. The path length from the ZL6QH transmitter,
at Quartz Hill, near Wellington, New Zealand, is estimated as being
11,709 km.
Bob Vernall ZL2CA Organiser of the Trans-Pacific tests
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