DPN 7MHZ QRP Transmitter

R1                            1   100R,Resistor (USA Style)
R2                            1   10K,Resistor (USA Style),..
C3                            1   10nf,Capacitor
Q1                            1   2N2222,Bipolar Transistor
L1                            1   30t on 1/2inch PVC pipe,Inductor,..
R3                            1   330R,Resistor (USA Style)
C2                            1   330pF,Capacitor
R4                            1   33K,Resistor (USA Style)
C4                            1   365pF,Capacitor Variable
Q2                            1   BD139,Bipolar Transistor
J1                            1   COAXJ,Coax Jack
G1                            1   GND,Chassis ground
T1                            1   Modulation Transformer,Dual Sec. Transformer w. pins,P
T2                            1   Shortwave,Transformer,4
C1                            1   VC1,Variable Capacitor
X1                            1   XTAL,Crystal

Output power of this transmitter is around 0.8 watts sufficient enough for qrp operation.This circuit uses easily available old radio junks like shortwave osc.coil , audio output transformer, 2J variable gang condensers, which makes your job easy. If you have any suggestions or modification ideas please let me know at bcdxer@hotmail.com.

Thanks

455 KHZ Beat Frequency Oscillator

This simple BFO can be useful to resolve SSB signal in your shortwave radio receiver. Keep the wire from bfo near to ur receiver when you logged a ssb signal and tune the core of IFT till better audio.

Low Cost ATU for QRP rigs

The circuit shows simple low cost ATU for QRP transmitter projects. The coil is wound on a 12mm ferrite rod, which can be junked from old radio receivers.The wire will be 20swg and  the winding should occupy 4cm long.VC1 and VC2 are 365 pf Variable condensers used in radio receivers.

Simple 80M transmitter

Simple 160M Novice transmitter

Simple audio S meter

21MHz DSB Transmitter

 

See the circuit! DSB transmitter has no need of a crystal filter. It does not need a frequency transverter. It is easy to make. And it can make QSO with normal SSB stations. Therefore DSB is best modulation for the amateur radio builder. The mic amplifier makes the audio signal stronger. The VXO oscillates a 10.6MHz signal. This is doubled by the amplifier of the TA7320 IC. These two signals are modulated by the DBM of the TA7320. There comes the 21MHz DSB signal. HF amplifier makes this signal to 250mW.

3 transistor 50MHz DSB transmittor

 

 

Input transformer of this circuit is an audio transformer. The output transformer of this modulator is made by coil. This modulator is understood as a pair of base grounded amplifier for the carrier. But two output of collector is connected as other side of a coil. Therefore the carrier is balanced and can not be out for the antenna connector

2SC1957 linear AMP

Single transistor FM transmitter

This is oscillator using a crystal. This oscillator makes the wave 5 times of the crystal. 19.2*5=96MHz. And the frequency is modulated by the audio signal came from the base of the transistor.Do not joint the antenna wire for this transmitter! The frequency of this transmitter is stable than self oscillator. But it is not so stable as a normal crystal oscillator. The antenna wire changes the frequency.

Simple L-MATCH ATU for End-fed wire antenna

Super simple CW transmitter

The figure shows super simple CW transmitter with bare minimum components

80M QRP 3 watts Transmitter for novices

Ramsey HR-40 CW/SSB Direct Conversion Receiver

Schematic diagram for the Ramsey HR-40 CW/SSB Direct Conversion Receiver. Ramsey Electronics Inc

Figure shows the circuit for the HR-40 Direct Conversion Receiver for 40 meters. Here’s how this circuit works. The incoming signal from the antenna is coupled through C5 and the RF gain control R1, to antenna input transformer L1. (A 10.2-MHz IF transformer, detuned to cover the 40-meter band, can be substituted.) This “tuned” transformer peaks the  desired signal and applies it to the NE602’s mixer section. The shielded oscillator coil, L2, along with varactor diode D1, R2, R5, C1, C2, C3, and
C4, form an oscillator network with the NE602’s internal oscillator. Rotating R2 varies the oscillator’s frequency over a tuning range of about 250 kHz. The NE602 mixes the incoming RF signal with the signal from the internal oscillator to produce an audio signal at Pin 4. The output audio signal is coupled to the LM 386 audio amplifier via coupling capacitor C8 and volume control R3. Capacitor C9 boosts the voltage gain of the LM386 to about 50. The high-level audio output is coupled from Pin 5, U2, to external headphones or a low impedance (4 to 8 ohms) speaker through coupling capacitor C12 and output connector J2.NE602.

An internal 9-volt transistor battery (or an external power source of about 9–12 Vdc, 60 mA) is used to power the HR-40. Note that zener diode D2, along with C10 and R4, form a 6.2-Vdc voltage regulator network to improve stability of the NE602’s internal oscillator circuit.

A simple crystal receiver for the beginner

A simple crystal receiver for the beginner

Ramsey Electronics Model QRP-40 CW Transmitter

Schematic diagram for the Ramsey Electronics Model QRP-40 CW Transmitter. This easy-
to-build CW transmitter provides about one watt of output RF power in the 40-meter
band. Ramsey Electronics Inc.

Code practice oscillator

Schematic diagram for code practice oscillator circuit using the Signetics NE555 IC
Timer.

Cigar·lighter polarity Tester

Before you plug your equipment into the cigar lighter of your new (or an unknown) car, it's a good idea to test the lighter polarity. Fig shows a simple means of doing this. The circuit tests for a center positive condition at the lighter; if the lighter is powered, and + 12 volts is connected to its center contact, DSllights. Carry this gadget with your "pluggable" 12-V gear; it could save your transceiver from a quick demise.