Soviet tank industry outpaced the electronics industry. As a result, until 1943 "premium" tanks like the T-28, T-35, and KV were all built with radios, while "ordinary" tanks like the T-26, BT, and T-34 did not. About half of these tanks received radios until 1943, after which radios were installed on all tanks.
Even in the Spanish Civil War tankers noticed that the enemy attempted to knock out tanks with large frame antennas first. The introduction of smaller whip antennas made it easier to hide commanders' tanks, but they were still visually distinct. This was resolved in an obvious way.
"To the Chief of Staff of the 3rd Mechanized Corps
From the 1st Mechanized Brigade
Fake whip antennas have been installed on the tanks.
October 21st, 1942"