1,5 Watts FM broadcast transmitter (87,5-108 MHz), 50kHz stepsize, dual-speed.
(Hartley oscillator version)


Resistors (¼ watts carbon or metal film)
(values are in Ohms, unless otherwise noted)

R1 = 470
R2 = 12k
R3 = 680
R4 = 1k
R5 = 22k
R6 = 22k
R7 = 22k
R8 = 56
R9 = 220
R10 = 3k3
R11 = 1k
R12 = 220
R13 = 47
R14 = 220
R15 = 470
R16 = 150
R17 = 150
R18 = 68 or replace by a VK200 wideband choke
R19 = 270
R20 = 47 (for a 2N4427) else a VK200 wideband choke
R21 = 100
R22 = 10k
R23 = 10k
R24 = 390
R25 = 390
R26 = 22k
R27 = 10k
R28 = 10k
R29 = 10k
R30 = 10
R31 = 10
P1 = 500, adjustable, Piher 10 mm Ø, horizontal mount
P2 = 1k, adjustable, Piher 10 mm Ø, horizontal mount

Capacitors

C1 = 100µF/25v
C2 = 47µF/25v
C3 = 100pF (np0)
C4 = 10nF
C5 = 1nF
C6 = 10nF
C7 = 1nF
C8 = 470µF/25v
C9 = 1nF
C10 = 1nF
C11 = 1nF
C12 = 10uF/25v
C13 = 60pF trimmer, Philips (yellow color) or similar
C14 = 60pF trimmer, Philips (yellow color) or similar
C15 = 1nF
C16 = 60pF trimmer, Philips (yellow color) or similar
C17 = 60pF trimmer, Philips (yellow color) or similar
C18 = 56pF
C19 = 56pF
C20 = 56pF
C21 = 27pF
C22 = 10nF
C23 = 10pF(*) optional
C24 = 100nF/63v (MKT)
C25 = 22uF/25v
C26 = 100nF
C27 = 22pF trimmer, green
C28 = not used
C29 = 100nF
C30 = 1nF
C31 = 100nF
C32 = 100nF
C33 = 10nF
C34 = 22pF (np0)
C35 = 22pF (np0)
C36 = 1nF
C37 = 10µF/25v
C38 = 1nF
C39 = 10µF/25v
C40 = 10µF/25v
C41 = 100nF
C42 = 100nF
C43 = not fitted (was 39pF)
Cx = 3n9 (50µS) or 4n7 (75µS) pre-emphasis (this capacitor can be omitted when using an
     MPX-signal to drive the unit.)

Note: mount a 10pF (1206 SMD-chip capacitor) between the base and collector of T7

Semiconductors

D1 = BB809, Philips, Yellow band
D2 = 1N4148
D3 = LED, Green, 3 mm
D4 = LED, Red, 3 mm
T1 = BF981
T2 = BFR91
T3 = BFR96(S)
T4 = 2N4427 or 2N3553 (either with heatsink)
T5 = BC557B
T6 = BD139
IC1 = 78L05
IC2 = 78L09
IC3 = 78L05
U1 = TSA5511 (Philips)
U2 = PIC 16F84(A) or PIC 16F628(A)
LD1 = 1x16 character LCD display with backlight, HD44780 compatible (optional)

Coils

L1 = 4.5 turn, 6 mm diameter, 1 mm CuAg, tap 3/4 to 1 turn from ground (spaced)
L2 = 3 turn, 5 mm diameter, 1 mm CuL (closewound)
L3 = 5 turn, 5 mm diameter, 1 mm CuL (closewound)
L4 = 3.5 turn, 6 mm diameter, 1 mm CuL (closewound)
L5 = 3.5 turn, 6 mm diameter, 1 mm CuL (closewound)
L6 = 3.5 turn, 6 mm diameter, 1 mm CuL (closewound)
L7 = 3.5 turn, 6 mm diameter, 1 mm CuL (closewound)
L8 = 10µH, moulded choke
L9 = 10µH, moulded choke
L10 = 10µH, moulded choke
L11 = VK200 choke

Misc.

X1 = 3.2 MHz crystal, 30-32pF, parallel res.
X2 = 4 MHz crystal
J1 = 14 pin boxed header, pcb mount, (90°angle)
S1 = push button ("ON" when pressed)
S2 = push button ("ON" when pressed)
S3 = push button ("ON" when pressed)
JP1 = 2 pins header + jumper

Notes

(*) not used
CuAg = silver plated copper wire
CuL = magnetwire, enameled copper wire
(Note: 1 mm CuL approx. equals to AWG18
         0,3 mm approx. equals to AWG28)

(I) all diameters are measured from the inside of the coils, i.e. 'internal' diameters

D3 indicates if the PLL is locked
D4 indicates if the PLL is not locked

(C)2006-2007 Lorian, The Netherlands.

THIS DESIGN IS *NOT* TO BE USED FOR COMMERCIAL PURPOSES!

(Sunday, January 14, 2007 (rev.3))
