On 25 May 1928 the airship “Dirigibile Italia” during its return trip to the base in Ny Alesund,
after overflying the North Pole, shipwrecked on the ice pack in a region at about 400 km northeast of
Svalbard Islands. Survivors, by using a portable high frequency (HF) radio transmitter, tried unsuccessfully
to send SOS messages and to establish a radio link with the ship “Città di Milano” of the Italian Navy,
closely anchored at King's Bay. Only after 9 days of repeated radio distress transmissions, a Russian radio
amateur close to the town of Arkhangelsk about 1,900 km away was able to receive the messages launched
by the survivors and raise the alarm.
HERE the full Article -
SUMMARY OF CONCLUSIONS
... At the beginning of July, they modified the antenna and reduced the frequency to 6.4 and 6.5 MHz in transmission and to
6.5 and 5.4 MHz in reception, so to obtain a finally stable radio link between the Red Tent and the ship....