Here are a few interesting Projects on how to jam AM and FM signals. Keep in mind that it is Only Legal Indoors. If you do it outdoors and get caught it can result in a 5000 dollar fine and or 2 years in jail. Like broadcasting systems, you need a license to do this Outdoors. Jamming signals are More Illegal than sending radio signals on the air.
The Am type Radio jammers can usually with a 5-foot antenna travel 5-10 feet while the FM 555 timer can travel 30 feet max.
I want to share how to do so. It only Illegal if done outside so do it Inside Only OK?!
Also it very dangerous to deal with High voltage like Solid state transformers, etc if you don't know what you're doing! You could get killed if you touch the arc of electricity while it is ON! High voltage Arcs will Jam both AM, VHF, UHF (Ultra High frequency) radio signals as well as SSB, etc. It has a wide range frequency too. Test it with VHF, etc before.
Step 1: AM Radio Jammer Then FM Jammer.
I will show you how to build FM and AM jammers with youtube videos since the diagram can be difficult to follow.
Here are some videos on it.
These are using One transistor mine use 2-3 or a 555 timer.
Step 2: More Info on How to Build a AM and FM Radio Jammer.
Here a few Instructables on how to also do it with High Voltage.
Also, an AC Jacob ladder which is very easy to build could produce a more powerful Radio Jammer. Just make sure the current is no more than 35 mA. I used a 12 kV and 35 mA solid state transformer.
Also be very careful with the High voltage parts of the device while it is ON.
Step 3: Final Note: Have Fun With the Jacob Ladder or AM and FM Radio Jammer.
As a final Note be careful with High voltage and check your state or province to make sure this is Legal even if done Indoors. The second page talks about the 160 in 1. You can buy it on e-bay or make it yourself. It the 160 in 1 Science fair Radio Shack Electronic kit from the 1980's.
Downloading the pics will help you build some AM and other Jammers too.
Good luck and make sure what you do Is Legal!!