Medium range locator The P-37 is a Soviet medium range two dimensional discovery and locating radio locator. The model was developed in the mid-1970s based on the P-35 model. Compared to its predecessor, interference protection, protection against hostile radio electronic activity, and range were increased. It is used by former member countries of the Warsaw Pact as well as Middle Eastern and African countries. NATO reporting name: Bar Lock. Use in Hungary The Hungarian National army adopted the model in 1976 and continues to use a modernised version of it for the protection of our airspace. In total there are 21 in use. Domestic modernisation of the locator began in 1997. The first modernised issue was handed over to the Hungarian National Guard by HM Arzenál Inc. in 1999. The so-called backbone radar companies under NATO supervision (64/11 – Kup, 64/12. – Juta, 64/21. – Debrecen, 64/22. – Békéscsaba) have three operational P-37s each.