I have seen many reports that our government plans to and has already in some cases block cellphone signals during moments of civil unrest i.e. Occupy protests. We know that the S.F.P.D. B.A.R.T. unit blocked cellphone access during a protest on August 11th 2011 in an attempt to keep protestors from calling friends for help. There was also a two hour outage during the Occupy N17 march. This may have been done in an attempt to try and stop live streaming video during violent arrests but we don't know. What we do know is as of right now the F.C.C. says blocking cell phone signals is illegal yet in at least one case we know the police have already done it.
The question now is what can we do to counter act if the police decide to do it again? Well one thing we could do is jam their communications right back. You don't believe me? Well take a look at this. By now I am sure we have all heard about the plan to Occupy Congress on January 17th 2012. So I did a little digging and in less than 20min I found the radio frequencies for all emergency departments in the District of Columbia and found out some interesting information. It seems that all the law enforcement agencies communicate on a small band of frequencies. Some of which are open to eavesdropping and the ones that aren't operate in P25 mode and are encrypted. The problem with P25 mode is that it's "highly vulnerable to jamming and unauthorized decryption".
I figure if a motivated individual or group of individuals wanted to listen in or jam the local and federal law enforcement during the January 17th action, all they would have to do is go to a website out of say China maybe and for the right price they could get everything they would need. To be clear I am not saying anyone should do anything like this I am just saying we could if we so desired. Now I am no lawyer but I would bet doing such a thing is illegal but than again so is blocking cellphone signals and as I have shown it didn't stop them.