π-box - How to build an antenna

Material

* One Coaxial female adaptor

First, prepare the Wire, connect the wire to the coaxial female adaptator.

Connect the wire to the GPIO Jumper.

Add some tape.

The wire is ready, now let's make the antenna

open the coaxial T, take off the balloon, disconnect one output, break the cover of the side coaxial output.

cover it back with tape, open slightly the male plug so it can host one telescopic antenna then connect the wire.

Ready for transmission !

Test transmission with pi-box + dipole antenna made with rigid aluminium tube

Test transmission with pi-box + dipole antenna made with flexible copper cable

Test transmission with pi-box without antenna

Test transmission with transmitter 5 watts (?) with an antenna fixed to a bike (a bike as antenna)

Simple dipole antenna by Tetsuo Kogawa https://anarchy.translocal.jp/radio/micro/howtomakeantenna200708.pdf
Antenne dipole http://www.petoindominique.fr/php/antenne.php
Antennas types and calculs http://exam2ham.free.fr/donnees/antennes.html
How to calculate the lenght of a 1/4 wave or 1/2 wave antenne ? http://www.bmweb.fr/radio/mat_antennes.php
Basics of the antennas BAsicsOnAntennas-an-00500.pdf
Build a low tech antenna with agricultural material https://www.instructables.com/id/Low-Power-FM-Transmitter-Antenna-From-Agricultural/ For example, to build a dipôle antenna for 108 MHz frequency, with 2 tubes of coper, the global lenght of the antenna will be 1389 mm, if we let 1 cm of space between the 2 tubes of coper, then each tube must mesure ~ 68,9 cm