XPost: rec.radio.amateur.moderated, rec.radio.amateur.equipment
EI7GL....A diary of amateur radio activity
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Weak opening from Europe to Australia on 50 MHz - 29th May 2021
Posted: 30 May 2021 04:00 AM PDT
https://ei7gl.blogspot.com/2021/05/weak-opening-from-europe-to-australia.html
Sat 29th May 2021: It looks as if there was a weak opening from Europe to Australia on the 50 MHz with a few weak FT8 signals making it through.Txmtr
Rcvr Band Mode Distance Time (UTC)DF5VAE VK4HJ 6m FT8 15477 km
06:05:29UT7UV VK4HJ 6m FT8 14545 km 04:18:44
SP3MM VK4CZ 6m FT8 15564 km 07:10:14
VK4CZ UT2XQ 6m FT8 14683 km 06:59:59
SP4K VK3OER 6m FT8 15383 km 05:17:41
It looks as if there was a successful FT8 contact between VK4CZ in
Australia and SP3MM in Poland, a distance of about 15564kms. The signals
seem to have been quiet weak and were in the range of -16dB to -20dB which
is below what is audible to the human ear i.e. a cw contact would not have
been possible.
As for the propagation mode, it seems likely it was multi-hop Sporadic-E
with possibly eight hops required. I say 'likely' as I sometimes wonder
what are the chances of getting eight Sp-E hops in a row at 50 MHz.
We still have all of June to go yet so there could be more openings on 50
MHz from Europe to Australia.
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10-milliwatt WSPR signal on 28 MHz heard in Ireland - 28th May 2021
Posted: 29 May 2021 01:04 PM PDT
https://ei7gl.blogspot.com/2021/05/10-milliwatt-wspr-signal-on-28-mhz.html
Friday 28th May 2021: I left the radio monitoring the WSPR frequency on 28
MHz for whole day and I heard signals from all over Europe including DP0POL
on the German Icebreaker ship near the north of Norway.
At the end of the day, I got an interesting e-mail from Andreas, DL2KCL
about my reception of his very low power WSPR beacon during the day.
Andreas wrote... "You received a transmission from my homemade WSPR-TX on
10m. The TX puts out 10 mW directly from a Si5351A-chip. No PA. It runs
from a single rechargeable D-cell with a DC/DC-converter (85 mA).
The antenna is a piece of about 2.5 m thin wire wound on a 18 cm PVC tube
in resonance on 28.2 MHz. There is no additional counterpoise."
I checked back through the WSPR logs and amazingly, I had heard the 10-milliwatt signal from DL2KCL a total of 77 times during the day. The
weakest signal was -27dB which is buried way in the noise. The strongest
signal was -12dB which would have been just about audible to the human ear.
The photo above shows the transmit antenna which is just a quarter wave of
wire wound on an 18cm PVC pipe. To hear such a low power system 77 times
during the way just goes to show how good conditions must have been.
On my side, I was just using a simple CB type half wave vertical so there
was no additional gain to pull in weak signals.
Analysis: The one crucial part of equation is the distance... 1075kms.
During the Sporadic-E season, signals in the 1000 to 1500km range are a bit like the sweet spot on 28 MHz.
There are a lot more openings on 28 MHz compared to the higher bands like
50 MHz and signals around 1100kms are at the very least 6dB stronger than
those out around 2200kms just due to the fact they are closer.
The signals at 1100kms are also coming in around 8 degrees above the
horizon which allows it to clear local obstructions at either end of the
path.
Antennas on 28 MHz will probably have more gain at 8 degrees above the
horizon in comparison to say 1 or 2 degrees and a 2000km skip distance.
It just goes to show how good the 28 MHz band can be when the conditions
are right.
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