** Shares of communications firm Siyata Mobile rise more than double in premarket trading
** SYTA stock was last up 131.7% at $2.34, making it one of the top gainers on Nasdaq
** Co's cellular radio handsets will be available on T-Mobile's 5G network for first responders to use in critical situations
** Up to Friday's close, stock had fallen 98.7% this year
(Reporting by Rishi Kant in Bengaluru)
((Rishi.Kant@thomsonreuters.com))