Recently, I've been to Istanbul and as I've never been in Turkey before I was quite interested to see how well the mobile networks would perform there. After all, 3G only started in Turkey in late 2008 so they haven't had much time to play catch-up.
To my delight, the networks performed flawlessly and 3G coverage was good in all except one place I was throughout Istanbul. The hotel I was staying in the Maslak district even had dedicated 3G indoor coverage from one network operator so Internet access even on the 17th floor was quick. Quite interesting to see that towards the windows, 3G interference quickly grew and speeds slowed down. However, just a meter or two into the room and around a corner, the interference from outside cells was gone.
The one coverage exception mentioned above is metro line 2 from Taksim square to Maslak. There is 2G coverage in the underground stations and in some parts of the tunnels but no timeslots have been configured for GPRS or EDGE!? I tried all three operators and they all had their GSM networks configured for voice only (+SMS) in the metro system. I have to admit I don't quite understand that!? I don't think its for security reasons and I also can't imagine that the Istanbul underground authority has never heard of mobile Internet on phones. So why? Anyone? Capacity perhaps but if so, they are just doing it on the cheap as other cities are very well capable of having sufficient voice and data capacity in the metro, with 3G no longer only an "over ground" technology.
Initially, I wanted to buy a local SIM for Internet access as I usually do but this time I decided to use my Vodafone Germany prepaid SIM and daily Websessions. That worked very well but was a bit more expensive than a local SIM card. Next time perhaps.