- The modulator. Audio input is from the "headphones out" from
below: a build by Channel Z Radio and received over 2000 miles away on 6964 KHZ
a computer, or portable MP3, CD, or tape player.
- The Guerrilla - AM transmitter, 6 watts, class-E, flyback mode, for 75 and 40 meters, and beyond.
( last update: July 9 2007 )
- The modulator. Audio input is from the "headphones out" from
below: a build by Channel Z Radio and received over 2000 miles away on 6964 KHZ
a computer, or portable MP3, CD, or tape player.
XTAL - crystal
Q1 - 2N3053
Q2 - IRF510
R1 - 100K ohms
R2 - @ 4 MHZ 100 ohms, @ 7 MHZ 68 ohms. .5 watt rating.
R3 - 2200 ohms, but anything from 1K to 10K is OK here.
R4, R6 - 10 ohms
R5 - 470 ohms. ( adjusts gain of modulator )
R7 - 1000 ohms
R8, R9 - 1000 ohms
R10, R11 - 100 ohms
C1, C2 - 82 picoFarad, but anything from 82 to 120 pF is OK. Silver mica type is best.
C3 - .01 µF disc
C4 - output shunt capacitor. for 3.9 MHz; 680 to 1000 picoFarads, 100 V., for 7.2 MHz; 470 picoFarads, 100 V.
C5 - 1200 picoFarad, silver mica, 100 V., But a compression trimmer capacitor
that covers up to around 2000 pF is best, for tuning up.
C6 - 47 µF, but anything from 10 to 470 µF is OK here, 3 volts or greater rating.
C7 - .1 µF disc ceramic
C8 - .1 µF disc ceramic
C9 - .1 µF disc ceramic or film, mounted close to the junction with T1 (also, add one near the junction with L1 )
C10 - 100 µF electrolytic, with at least a 15 Volts rating.
C11 - .047 to .1 µF
C12 - 1000 µF electrolytic, with a 12 volt or greater rating.
C13 - 2.2 µF, but anything from 1 to 4.7 µF is OK.
C14 - trimmer capacitor. 65 pF, or a fixed value capacitor 22 to ? pF.
C15 - .1 µF disc ceramic
C16 - .1 µF disc ceramic
L1 - flyback inductor, 24 turns of AWG #20 or 22 on a T50-2 core.
L2 - for 3.9 MHz, 16 turns. for 7.2 MHz, 11 turns. AWG #20 on a T50-2 core.
L3 - for 3.9 MHz, 40 turns. for 7.2 MHz, 23 turns. AWG #30 on a T50-2 core.
L4 - have the reactance of this inductor be 50 ohms.
T1 - The modulation transformer was made from a choke core, Radio Shack p/n 270-030A.
Remove the bobbin, and the wire on it. Using AWG 20 or 22 magnet wire,
wind 55 turns, stop and twist for the center-tap, then continue on with 75
more turns. The end of this winding is +Vmod, going to the transmitter.
U1 - TDA2003
There are pictures, at this link:
CLICK HERE
( from Dave Martin's Corsair webpages: http://www.geocities.com/thecorsairtx/The_Corsair.html )
of a modulation transformer being made from a 270-030A inductor. This transformer will work in
The Guerrilla transmitter also. Have the side with the additional 20 turns, going to the primary side
at U1, and change the polarity of C12.
. . . that's all folks, from radioanarchy. . . . . . . . .