Cat not using her box.

Is it unusual for my cat to not pee in her box when she is in heat?  It seems she is in heat every other week.  When she acts this way her meow is different amongst her presenting herself.  There are four fixed male cats in the house, but they do not have any interaction.  Could the smell coming from the males cats be causing her to problem?  I hope y'all can help me.  

[PrettyKitty1]

A cat that is not fixed WILL pee outside the box. You got it! When you get her spayed she will stop doing this. It is not the scent coming from a neutered cat that sets her off. It is her way of letting them and everyone else know she is being territorial. She is marking her space with her urine. She owns it!

What are you using to clean up the area? Does she pee in one place or is it just where she pleases? Different areas around the house?

[opus88]

PK is so right!
also a female will continue to come into heat until she becomes pregnant.
she needs to be fixed asap