In those days, radio stations were large, heavy, and bulky. The group could not afford such a heavy ballast. Their own backpacks, quilts, and tent weighed between 20 and 40 kilograms, and the route to the summit led through one-and-a-half-meter-high snowdrifts.
It seems puzzling in this situation that the leader of the expedition, Igor Dyatlov, not only came from a family of inventors but was himself an eager constructor from an early age.
One of his inventions was a portable, compact radio station, whose dimensions are compared to modern cell phones. Igor worked on it to improve the quality and safety of mountain expeditions. He has used it many times on previous treks, so why not take the device with him this time?
The expedition plan submitted by Dyatlov to the Sverdlovsk City Committee of Physical Culture and Sport included a note about a radio transmitter in the equipment, but it was definitely not there. The question remains whether the information given in the plan was false, or the radio transmitter disappeared sometime during the expedition.
