General   Practice    My Dipper


The project was on an old Handbook and it's easy to build and efficient;

electric diagram of my dipper

It's a Colpitts oscillator with a variable capacitor and changeable coils; mosfet RCA 40673 (I used a common BF960 or similar) oscillates on a frequency determined by L1 and C4; oscillation is always stable; R2 sets the gain of Q1 and you need to use it just sometime; RF signal generated by Q1 is rectified by D1 and amplified by Q2, a common 2N2222A (you can use any NPN transistor); R7 sets the amplification of Q2 (the meter gain); it's possible to take the RF signal from C8 and send it to an external frequency-meter (or to use dipper as signal generator). S2 switch dip or wave meter. There is only a small 9 V battery.

frontal view of my dipper

I must say you that I built my dipper on 15 August, when all shop were closed; I needed it to tune my new quad antenna quickly because 19 August I'll go away in army...; so you can see that I built it using disparate materiales: the box was built using the same stuff of printed board, the meter cames from an Hi-Fi ecc.: but it works and costs as ...a coffee!

component position




Radio Rivista 10/92 pag 23
Radio Rivista 4/95 pag 30
Radio Rivista 8/97 pag 27
Radio Rivista 8/94 pag 45
Radio Kit Elettronica 3/89 pag 28
Radio Kit Elettronica 2/88 pag 21
Radio Kit Elettronica 5/89 pag 29
CQ Elettronica 11/89 pag 32
CQ Elettronica 4/89 pag 36
CQ Elettronica 7/97 pag 77
Nuovo Manuale dei Transistor (G.KUHN) pag 265

73 de iz7ath, Talino