About FFT and Fast Frecuency Hopping

Suppose i have a symbol of 64ms of duration (512 samples). Then i can run
a FFT(512) to get metric. 

But, i want to probe something different. You imagine i divide the symbol
received in 4 chips (like a Fast Frecuency Hopping of 4 chips by symbol),
then i run 4 FFT's, one for each chip and i would like add the 4 FFT's of
any manner without loss energy.

Example: I take 1/4 of symbol (128 samples) and i do zero padding until
get 512 points. Then run FFT(512). And so for 4 times. 

Finally, i add the result of the 4 FFT's:  

  FFT(512) = FFT_Chip1(512)+FFT_Chip2(512)+FFT_Chip3(512)+FFT_Chip4(512)

I have run this, but i loss 3dBs of Es/N0. How i can add 4 FFT's without
loss dBs?

Ok, all right.

The problem is that if Chip Time is 1/4 of symbol, then the number of
points of FFT would be 512/4.

Solution:

 FFT(128) = FFT_Chip1(128)+FFT_Chip2(128)+FFT_Chip3(128)+FFT_Chip4(128)