The most common types are split into two main categories: obvious and subtle and unintentional versus Deliberate.
For example China is strict with what is allowed to be broadcast; they want to prevent foreign radio stations being listened to in their country, so they will disrupt the information flow by playing a continuous loop of Chinese music blocking the broadcasts. This is a very obvious type of jamming and is also a deliberate form of jamming.
Jamming a signal is as simple as overriding the signal at the receiving end of equipment with enough power.
In ‘war zones’ where radio/mobile phone triggered IEDs (Improvised Explosive Devices) can be a threat, radio jamming is essential. By blocking the signal this will stop the perpetrator from being able to intentionally set off the IED, therefore it is an extremely vital part of the protection of ground troupes and vehicles.
Interrupting radio transmissions isn’t always intentional; here are a couple of unintentional examples:
When the operator doesn’t check the frequencies before transmitting, he could transmit on one that is very busy, so his transmission won’t be picked up.
Sometimes equipment will radiate signal, which has been known to emit on an emergency frequency.