FRB 6 Watt RF Amplifier Kit
Assembley Instructions

Assemble by soldering the components to the pads indicated. Keep coil, resistor, and capacitor leads as short as possible. The coils should be 3/16" to 1/4" above the board and separate turns by one wire diameter. Bend leads to form a little mounting foot for soldering to the circuit board. Tuning and power output are affected by the distance between the coil turns, you can make fine adjustments by either spreading or compressing the coil slightly. The area surrounding the pads is ground. C2, C3, C4, C6, C7, C8, C9, C10, L2, and R1 are soldered at one end to ground as well as the shield braid on the coax cables. Bolt Q1 to a small heat sink or the chassis with heat sink thermal compound or gray thermal pad underneath the tab. With an input level of 200-500mw, you should see an output of 5-6 watts. Be sure to have a proper dummy load (50 ohms) or tuned antenna connected to the output, doing otherwise will likely destroy the transistor.

Schematic

Parts List

Quantity	Description	Part Number(s)
2	470 pF mica capacitor	C1, C5
1	75 pF mica capacitor	C2
1	39 pF mica capacitor	C3
1	12 pF mica capacitor	C4
2	0.001 uF disc or monolythic capacitor (marked either 102, .001, or 1n)	C6, C8
2	0.1 uF disc or monolythic capacitor (marked either 104, .1, or 100n)	C7, C9
1	10 to 22 uF electrolytic capacitor (observe correct polarity)	C10
1	1 turn #18 tinned copper, 1/4" dia.	L1
1	1 uH inductor, blue lumpy item	L2
1	2 turns #18, 1/4" dia.	L3
1	7/10" #14, hairpin	L4
2	5 turns #20, 1/4" dia.	L5, L6
1	56 ohm resistor with ferrite bead over lead at the base of end of Q1	R1
1	2SC1971 RF transistor	Q1
2	SO239 socket
2	banana plug (1 each red and black)
2	banana socket (1 each red and black)
1	ferrite bead
4	4-40 nuts
4	4-40 bolts
	RG174 coaxial cable
	hookup wire
	soldering lugs

Η ενίσχυση του τηλεοπτικού σήματος απαιτεί ένα γραμμικό ενισχυτή, όπου η τάση Vout θα είναι ευθέως ανάλογη της τάσης εισόδου Vin. Ο ενισχυτής λειτουργεί σε τάξη Α ενώ το τρανζίστορ που χρησιμοποιούμε είναι το MRF237. Είναι τύπου NPN και λειτουργεί με τάση 12,5V και είναι σχεδιασμένο για να λειτουργεί σε τηλεπικοινωνιακές συσκευές εως τους 200MHz.

C1 - 10 μF/16V (τανταλιου)
C2 - 47 pF (κεραμικoς)
C3 - 2-60 pF (μεταβλητος)
C4 - 10 nF (κεραμικoς)

L1 - 7 σπειρες σε 7mm διαμετρο
L2 - 4 σπειρες σε 4mm διαμετρο
L3 - VK200
L4 - 10μΗ τσοκ
D1 - 1N4001
T1 - MRF237

C1, C2, C3, C4 = 10 – 80pF

C5 = 10nF

C6 = 1000pF

C7 = 100nF

C8 = 2200mF/35V

L1 = 1 σπείρα με διάμετρο 10mm, 1mm

L2 = 7 σπείρες με διάμετρο 10mm, 0,8mm

L3 = 3 σπείρες με διάμετρο 10mm, 1mm

TR1 = BLY89

RFC = RF τσοκ