How to use a frequency counter
In order to adjust your transmitter after building it, a frequency counter is indispensable. Please mind this seriously. A transmitting signal has many harmonic signals: say 100 MHz is the regular one, it has [1/n and n] x 100 like 50, 150, 200, 250, 300MHz ..... So sometimes you might misunderstand the ongoing frequency with the harmonic signals. You can catch them as if they were "real".
There are various types of frequency counters. This is a portable model.
The leads usually have each plus and minus alligator clips. You could bite them with a bare wire of 1 cm or so. This is a kind of 1 turn coil. So I removed the alligator clips and made a short-circuit.
When you figure frequency, you just bring the "one-turn coil" closer to the coil that you want to check the frequency.
how to buid a transmitter