Quarter Wavelenght Antenna

[DimaGS]

Hi!

I'm new at the site and I'm also a beginner in electronics. I start my school project: a GSM jammer. I want to know the bases of the theory for Antennas design and working which is an important part of my project. For the moment, I'm interested to know the frequency response of the quarter wavelenght antennas. I've made my investigations online, but I still have problems to understand what happens exactly in the range : f/10 to 10f.

Thank you so much and I hope you can help me to understand.

 

[JimB]

I start my school project: a GSM jammer.

What an irresponsible illegal project.

If your lecturer approved that, I would fail you and sack him!

JimB

 

[DimaGS]

It is only a school project in Mexico where it is perfectly legal and obviously I won't use it against people who are just walking on the streets. It is for my school to stop students which use their cellphones to get the answers online when they have an exam.
I hope someone else could answer me and help me. Like I explain before, it's a didactic project.

 

[MikeMl]

Quarter wave whips without a "ground plane" radiate about as well as a wet noodle. A transmitting antenna needs to have an end-to-end length of a half-wavelength. That can be a half-wave dipole, or a 1/4 wave monopole mounted right-angles to a conducting sheet that is itself a half-wave across. Google Ground-plane antenna.

 

[4pyros]

It is only a school project in Mexico where it is perfectly legal

It should not be allowed even in a school.
Do the kids in your school have to cheat that badly?

 

[unclejed613]

Ding-ding!!!! You win!!!!

johnny, tell the man what he has won.....


you have won a Marvin the Martian "I'm going to blow up the earth because it obstructs my view of Venus" award. candidates for Marvin awards include any "annoyance/revenge" devices, so your "school project" definitely qualifies.