Android 4g phone signal blocker - 4G Blocker Sales
As you probably already know, RCJ40-D is a multifrequency desktop jammer that is used as a powerful stationary jamming device against many types of frequency bands at the same time. It has many useful features like you can adjust its power of jamming signal output for precise territory jamming, and in addition the frequency ranges which this jammer will block are pre-determined by the future owner, i.e. by you.
Iridium satellite phone system that you are asking about consists of six orbits with 11 satellites flying each one of them, totaling in 66 satellites. They use L band to communicate with ground sources and this band has the working frequency of 1616-1626.5MHz, so yes, you can jam Iridium frequencies with RCJ40-D jammer.
By the way, their satellite phone, Iridium Extreme, can be also blocked with the same signal jammer, moreover it will block not only the communication signal of the satellite phone but in addition the WiFi hotspot that it can create and GPS tracking that it has.