[SFDXA] Propagation as a Matter of Life Or Death

[Bill]

/Great Story from the ARRL Contest Update/*
*

*Propagation**as a Matter of Life **Or**Death***

On May 25, 1928, the airship /Dirigible/ /Italia/ crashed on pack ice 
northeast of the Svalbard Islands, on its way back from a survey of the 
North Pole with 16 passengers and crew on board. At impact, one person 
was killed, and the cabin carrying nine people was separated from the 
hydrogen-filled airframe. Six crewmembers on the dirigible structure 
were never seen again as the airship became airborne again. The 
survivors on the icepack turned to their 5 watt wireless set to attempt 
to tell civilization they needed rescue, but it was only after nine days 
of trying that they were able to get the attention of a radio amateur 
1900 km away.

The recently published article "The Shipwreck of the Airship "Dirigibile 
Italia" in the 1928 Polar Venture: A Retrospective Analysis of the 
Ionospheric and Geomagnetic Conditions 
<https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020SW002459>" 
provides the gripping historical context, and tries to answer the 
questions of why it was so difficult to establish communications for a 
rescue. Drawing from sources of geophysical data collected at the time, 
and using modern theories of propagation -- including some directly 
derived from amateur radio observations 
<https://doi.org/10.1029/2018SW002008> -- the authors present data 
including sunspot count, magnetic flux, and F2 layer height, and take 
the reader through an analysis of the skywave and groundwave paths.

Ultimately, the authors suggest that groundwave path losses likely 
exceeded 100dB, leaving only the skywave as a potential link. In the 
initial few days after the crash, the ionospheric path was impossible at 
the frequency being used, due to disturbed conditions. It was only after 
conditions had settled that communication became possible, and only 
became reliable when a lower frequency was chosen.

We may complain about poor propagation, but the stakes are nothing like 
what the /Dirigible/ /Italia/ faced.

Even after communications were established, 15 rescuers were lost in the 
search and recovery operations, including Roald Amundsen, Norway's famed 
polar explorer. Finally, on July 12, 1928, 48 days after the initial 
crash, a Russian icebreaker was able to reach and rescue the survivors.

That's all for this time. Remember to send contesting related stories, 
book reviews, tips, techniques, press releases, errata, schematics, club 
information, pictures, stories, blog links, and predictions to 
contest-update at arrl.org <mailto:contest-update at arrl.org>

73, Brian N9ADG