Chronology - newest information first
[all transmssions on 136kHz unless stated otherwise]
- 25 November 2001: M0BMU pointed out that the difference
between amateur signals and the 73.25k Rugby transmission was 50
to 60dB.
- 25 November 2001: W1TAG had a problem:
I need to do some more detective work, but I have a strong signal
here in Massachusetts, from 73.2 to 73.3 kHz. There have been listings
of CFH on 73.6, but perhaps they have moved down to 73.25. In any
case, it makes it very hard to read a signal on 73.3. I will look
again tonight, but I doubt that 73.3 will be much of an indicator
from here.
- 25 November 2001: W4DEX reported that:
I lost all signal from the 73.3kHz RTTY station by 0100 UT last
evening. QRN was very high so the signal could have been just below
my noise level. Relative signal strength logged are as follows:
2100 UT -52 dbm, 2300 UT -48 dbm, 0000 UT -47.5 dbm, 0100 UT undetectable.
Bob, K3DJC, in Pa. also was hearing the signal.
- 24 November 2001: In response to a prompt by Peter, G3LDO,
that US stations should monigtor the 'Rugby RTTY' commercial transmission,
W4DEX said:
At 2100 hrs I am receiving a good RTTY signal on 73.3 kHz. Since
this is the first time I have listened for this transmission I have
no reference to judge it's current signal strength. It sounds strong
enough I almost believe it would print here if the static crashes
were absent. Last night was a complete wipe out for my 73 kHz reception
due to thunder storms in the area.
He posted a 15 second wav file (244kb) of the 73.3 kHz RTTY
signal at: www.qsl.net/w4dex/73khzRTTY.wav
- 24 November 2001: G3AQC attempted to find clues to predicting
good 73kHz propagation:
I have been looking at various solar numbers during the tests
and far from predicting when propagation will be OK I can at least
say when it wont ! During Wednesday night 21/22 Nov the Sun Spot
number dropped from 160 to 132, the Kp index was 1-2 and the Boulder
A index was 7. On thursday all these numbers began to rise, and
by last night S.Spot was 144, Kp was3 and Boulder A10. Today these
nos are still rising.So I shall continue to look for the low nos.
- 24 November 2001: W1TAG wrote:
Well, I guess it had to end. Absolutely nothing was visible
from Laurie or Jim on 72 kHz last night. I kept the screen on 120
sec dots, which precluded being able to see Peter[G3LDO].
A CME is due to arrive in the next day, so I suppose that will muck
things up for a while.
- 24 November 2001: John Gould, the RSGB HF Committee member
responsible for LF matters, commented that the recent transatlantic
successes made "our efforts to extend our usage on this
band, back in 2000, all worthwhile."
- 23 November 2001: G3NYK tried to analyse why the 73kHz
propagation suddenly came good: He wrote:
I have not made any measurements on signals as low as 73kHz,
but it looks from John's results on Laurie's signal, as though .
. . the big geomagnetic storm [has] not affected the lower frequency
for as long as . . . 136.
The normal final stages of the storms' effects on long distance
paths is first lots of very rapid fading (10 to 15 mins peak to
trough) . Over the next nights the fading period then seems to lengthen.
At 136kHz the normal pattern was often of two main peaks one about
midnight and other often better peak occuring about 60 to 90mins
before dawn in the UK. I have often seen a long dip between about
0200z and 0330z in the 137kHz path from CFH.
It is a useful approximation to remember that the shadow at 100kms
altitude (Bottom of E-layer) is about about 1000 to 1200 miles further
west of the shadow at ground level. The signal decays as the sunlight
ionises the region below, and the absorbtion produced wipes out
the path to the 'first reflection' point of a 2-hop path (about
1/4 of the transatlantic path length).
In some respects I am not surprised about the lack of other successes.
I have found that conditions on 136kHz can vary quite markedly over
just 20 to 30 miles, and there were at time quite considerable differences
between the the signals I recorded, and Laurie captured on his chart
recorder. I suppose it all depends on the happy conincidences of
path-lengths and signal phases from different interfering 'rays'.
Thus the three observations from John W1TAG, seem to follow a pattern.
The longer wavelength at 73kHz possibly means it is not so badly
affected by the multipath fading conditions as 136kHz. and paths
recover quickly. These conditions could be an enhancement on 'normal
flat conditions' as it is possible that there was some multipath
operating in Laurie and John's favour. We have seen 6 to 10dB enhancement
on 137kHz in similar conditions. It just goes to show....never mind
the theory, get on and try it !! Dead flat, quiet, solar conditions
may not be the best, it is seeming to suggest that the last gasp
of a big geomagnetic event could just provide the boost we need.
Well done all, keep the momentum up....we are still really just
stumbling around in the dark.
- 23 November 2001: John Andrews, W1TAG recorded this on
the 73kHz band from 0430 - 0545 UTC: Argo was set for 120 sec dots,
and as with the previous evening, there was some difficulty in separating
successive characters on the same line. He saw some fragments that
might have been from G3LDO. [Note: the letters have been added after
reception].
W4DEX, VE1ZJ and WB5MMB montored but saw nothing.
- 22 November 2001: Even better conditions resulted in G3AQC's
complete call being received by W1TAG who commented: Boy, what
a signal here tonight.
- Later he added: Below is a screen shot of G3AQC on 72.4013
kHz taken at W1TAG on 21Nov01 from about 0025 to 0120 UTC. This
is from ARGO, in 90 sec/dot mode. I tried 120 sec/dot, but there
was blurring between successive elements on a line. The 90 sec
version is much clearer, though there isn't as much vertical
separation between the dots and dashes. The "799.5" line represents
72.4015 kHz. Dashes are 0.1 Hz higher in frequency than dots.
I'll be amazed if someone else doesn't copy this tonight!
- 21 November 2001: After weeks of test transmissions, G3AQC's
73kHz signals were positively identified by John, W1TAG,
last night. John broke the news thus:
- It appears that I've at least got pieces of "AQC" on screen
captures from this evening. Will evaluate in the morning (U.S.
time), and let you know. It's been a long day! John Andrews,
W1TAG
- He later confirmed with:
- I did copy Laurie's 72.401 kHz transmission last night,
with parts of the signal being visible from 2330 to 0700 Z.
There were half hour periods with and without recognizable characters.
The best copy was from 0022-0052 and from 0452-0522 Z. For some
reason, I got a lot of very clear "A's." The "Q's" were more
difficult! I make the dash frequency as 72.4014 kHz. I have
sent screen shots directly to Laurie -- not sure if this reflector
would allow them. QTH is Holden, Massachusetts (FN42ch), about
80 km west of Boston.
- Laurie, G3AQC replied:
- Congratulations John, I dont think that there is any doubt
that the sig's you captured are mine. My dash freq was 72.4013
which compared to your measured freq of 72.4014 is well within
the limits of my measurment capability.The times at which the
signal peaked tie up very well with Alans earlier plots of CFH,
and the fact that two elements ie "A" are clear indicate that
the peaks are very short,the time to send a two element character
about 5 mins. This of course must be an amateur distance record
for 73kHz can anyone work out the distance for us please? I
will continue with the tests tonight since the sunspot No. and
Kp index seem to be dropping so best to make use of the opportunity.
73s and thanks Laurie.
- He later added:
- It has been a long haul involving 3 transmitters, and
many nights. My power last night using the Crawley club Decca
200mW ! I transmitted AQC only since I thought that would be
good enough for positive identification,however if necessesary
I will go to the complete call. My locator IO90nt, NGR- SU818019
- This is arguably a World record at 5291km, breaking Laurie's
own record of 4408km to VE1ZJ. I say 'arguably' because although
there is enough evidence to confirm that it really was Laurie who
was received, the complete callsign was not copied. Congratulations
to both stations.
-
2 September 2001: VA3LK reported "receiving DCF39
most every day, all day now (July and August), using a resonant
loop antenna and an EVM56 evaluation board for the dsp. I see
the frequency line 24 hours now, only rarely does it go away.
My bucket size is less than 1.22 milliHz and I can see the day/night
frequency change on DCF39 as well, variation is very small but
it is visible most days. I now feel that LF coverage is really
a matter of having a receiver and transmitter that are capable
of coping with the technical requirements - the signal is there
if you can get down to it in the noise. The limiting case is how
far down in the noise one can look and can the rx and tx be kept
on the frequency to permit the integration time to work properly.
I dont see any signals of course when the local noise gets very
high - amazingly this does not occur that often."
-
8 June 2001: G3NYK: "the path to CFH is opening about
0030z and peaking at about 0200 to 0230z. The path dies at about
0430z. there are some deep fades but the last few nights has seen
some faily long periods of high strength."
-
3 June 2001: VA3LK, listening on the UK-only 73kHz band,
heard a signal on 72.5kHz from Cutler, Maine. "Loud enough
at [VE1ZJ's] place and here in Ontario to be used as a substitute
for a razor."
-
3 Jun 2001: VE1ZJ identified
characters from G3AQC's 73kHz transmission! This is the lowest
frequency at which amateur signals have crossed the Atlantic.G3AQC,
estimates his ERP at between 125 and 140mW. He uses a 700W Tx
to put 3.5A RF into a marconi antenna with a 15m vertical section
and a 200m horizontal top.
The following are extracts from the rsgb_lf_group reflector as
the news broke:
-
Last night the K index was a 3. I have only seen Eu
twice when k is 3 es never when K was higher. I thought
I saw the number " 3" once es seven or eight minutes later
the letter "G". The freq , however, was wrong . It was more
like 71.921.5. Could that have been you, Laurie. I'm writing
this at work . As i remember it time was around 0150Z Condx
were disturbed last night Eu ,UA3,HA es G stations on 14
mHz were strong but ua9 es other Asian stations were very
weak, es I couldn't raise them John VE1ZJ
-
Great John, I think you did it ! my frequencies last
night :- Dash = 71,921.45 Dot = 71,921.35 as measured here,
+/- a bit I guess. Can you confirm the very close spacing
of my dots/dashes ? If so I think you have recieved the
very first amateur T/A signals on 73 KHz. I think its worth
trying again tonight, I will be on again from about 2200utc
until 0600 utc. Laurie, G3AQC
-
Hi Laurie, It looked like what I saw previously on 136.
Will Send picts tonight. If so congrats John VE1ZJ
-
Popagation pundit G3NYK commented: "well it looks like
Laurie may have been heard in Canada last night on 72kHz !!
Condition still seem to be quiet, though there was an M2.5
Class flare at about 0800z this morning, Hopefully the rubbish
from that will not reach us before tomorrow evening. There
did seem to be a slight rise in the proton flux, and I think
I have related that to a good night in the past.
-
2 June 2001: G3NYK noticed that: "the Kp index jumped
to 5 between 0000 and 0300z on june 2nd. This was due to a coronal
hole event. As conditions have been quiet it will be interesting
to see if this has any noticable effect in a day of two."
[G3NYK's propagation plots can be found on ON7YD's
site]
-
1 June 2001: Alan Melia, G3NYK, commented on possible
transalantic propagation:
"We seem to have had a series of overlapping small CMEs that
have kept up a level of absorption and deep fading on the night-time
paths. We are now into the time of the year when the night is
the shortest so the opportunities are more limited. A comparison
of [CT1DRP's] plots last night and my plots of SXV [approx 135.9kHz,
Greece] over the past few nights suggest that conditions are improving
and last night was quiet a reasonably good night. This suggest
that until we are on the receiving end of another 'glob' of solar
plasma LF propagation might be quite good."
"Brian's (CT1DRP) plot of CFH last night shows the features
of a 'good' night time path. It seems to show the path collapsing
at about 0400z."
"The Kp levels dropped to low levels (1-2) on Wednesday,
I do not expect problems until the is a major increase, and then
expect the paths to collapse about 24 to 48hours after the index
goes above 4."
[2000-1
transatlantic season] [Back to Transcontinental
index]
|