Ramsey Electronics QRP-80 Manual de instrucciones descargar pdf (Pagina 10)

HR-80• 10

RECEIVER ASSEMBLY:

 1) Install the RCA antenna jack, J1. Solder all four points.

 2) Install C5, a .01µF ceramic disc signal coupling capacitor. This

capacitor brings the signal up to the front of the PC board. Notice

the long PC trace from J1 through C5 to R1

 3) Install potentiometer R1, the RF gain control. Insert it into the

PC board so it seats firmly and is straight and even. Solder the

three pins and the two mounting tabs.

 4) Install L1(marked 5015-015), which tunes or preselects the

signal input from the antenna through C5 and R1

 5) Install U1, the NE602 IC mixer-oscillator. The marked end of

the IC (band or dot) must face the FRONT of the PC board. If you

wish, install an 8-pin DIP socket, still remembering to orient and

install the NE602 correctly. Please don't be afraid to solder U1

directly to the board as we have seen more repair problems with

DIP sockets than from direct soldering of IC chips.

The parts that we have put in so far bring the signal from the antenna

jack up to the RF Gain control (actually the RF attenuator) and to a

tuned circuit composed of L1 and its internal capacitor. Inductor L1

allows us to match and tune the 80 meter band signals to the

NE602’s input.

 6) Install C6, .01µF. This capacitor bypasses pin 2 of the NE602

to ground. Bypass means to provide a nice low impedance

(impedance means AC resistance) path to ground.

 7) Install R4, 270 ohms (red-violet-brown), which drops the 9 volt

battery supply to 6-7 volts, safe for the NE602.

 8) Install D2, 6.2 volt Zener diode. This is the smaller of the two

diodes and has a painted glass body. This diode acts as a

voltage regulator by keeping the voltage across it constant.

 9) Install C10, a 100-220µF electrolytic capacitor. Electrolytic

capacitors are marked by polarity and must be installed in the

proper direction. You’ll see that one side of the capacitor has a

black band and is marked with a ‘-’ sign, this is the negative side,

the other side is the positive lead. Make sure you insert the

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Ramsey Electronics QRP-80 Manual de instrucciones Pagina 10