The Russians found out the same thing when they did they detonated a 300 kT nuclear warhead only 150 km (93 miles) above the ground. The EMP seriously damaged power lines and even got a power station in the small city of Karaganda to catch on fire.
Ray; It does not discuss the Tsar bomb, but it does discuss the effects of an Exo atmospheric explosion in one of the links in 21. If you have something about what happened in Russia post it here!