bsnl 3g very weak signal strength

[Bsnl7.2]

I am from tumkur it is very much nearer to bangalore mostly 2 hours of journey.hai i had taken new bsnl 3g prepaid sim card on nov 19 2010 and i had purchased a Huawei e1750 3g usb modem 7.2mbps.device is working properly.At first week i am using free 7 days unlimited plan.at that time speed i am getting is 440 KB/s(Kilobyte per second) with IDM, but also the network disconnects lot and speed varies too much, after trial pack(my internet got disconnected after 7 days) . i get recharged with 4200 rs for 6months i thought that i can get download speed increases it will give constant speed. After recharging i am not getting even constant speed it getting at night time 150kbps connection speed even morning times also when i download by idm it varies upto 56 to 100 and suddenly it varies or disconnects.i am very much frustrated after i got recharged with 4200r.s some times it will get good speed speed when i use idm only if use web browser i will get only 50KBps onlyall i experienced is bsnl not fully upgraded to 3g. even at full signal strength my friend is not getting constant speed.it disconnects lot.my friend also got same plan.all i say don't get attracted by bsnl 3g plans.it has no paisa vasool.