Why the larger the spreading factor, the stronger the anti-interference ability?

Hi, everyone
I have found some information about the lora srpeading factor, it says that one symbol include 2^SF chips and can carry SF bits information. That means the larger the spreading factor, the more bits information a symbol can carry, but Why the larger the spreading factor, the stronger the anti-interference ability?

reference:

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Perhaps you can find the answer in the Semtech application note on Lora basics.

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If you compare SF7 and SF8, you have 1 more hit in the symbol, but the most important part is that th SF8 symbol is twice longer. So if you have an interfer long enough to kill 1 symbol SF7, at SF 8 you will only affect half a symbol which will be easy to demodulate.

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Thank you, I will find more detail in this application note, if I find out the answer I will write an answer in this question

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Yes, I agree. SF 8 is stronger in the anti-interference ability than SF 7 is beacuse that SF 8 has a longer symbol and and more chip in one bit. This is the best explanation in so far. Thanks!

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