1, Introduction:
"Shoes (PIXIE)" is a very small volume of the 40 meter band simple micro-power amplitude telegraph transceiver, using 9 ~ 13.8V DC power supply, this machine is the first popular abroad, after the introduction of domestic fans, " shoes "is" PIXIE "transliteration.
"Super Shoes (S-PIXIE)" was launched by LXQQFY.com, the following improvements:
Resistance to change is a horizontal packaging vertical packaging, easy to solve the short-circuit resistance has long been a problem.
Power input does not distinguish between positive and negative, and to improve the power supply range, the user can easily use 13.8V communication power supply, and do not worry about the positive and negative reversed losses.
Increasing the transmitter side as the buzzer sound prompts (using a jumper cap shielding sound), an increase of LED lights as transmitters prompt.
With transparent acrylic shell.
2, the main indicators:
Power Supply: DC9 ~ 13.8V (recommended linear power supply or battery), does not distinguish between positive and negative
Antenna: 50 ohm, 7MHz, VSWR 2.0 or less
Receiving Quiescent Current: 20mA
Emission current: 120mA
Transmitting power: 1.2W
Frequency: The oscillator frequency emission: 7023KHz; receiving local oscillator frequency: about 7023-7026KHz
Mode: CW
Key: Manual key
Automatic transmitter: Not supported
Sidetone: None
3, the circuit principle:
See schematics, 9018 with the surrounding elements constituting a typical Colpitts oscillator and keeps oscillating (it has about 1mW when receiving an oscillating signal leakage), the LO signal is coupled directly to the capacitor 8050. In transmit state (key press), 8050 as a C class amplifier, the signal is amplified by 100nF capacitive coupling to the π-type low-pass filter, and then send the antenna; in the receiving state (key release), and around 9018 elements constituting the beat oscillator (BFO), 1N4001 plus high-voltage, direct current with capacitive pressure is increased at both ends decreases, the natural frequency can be increased to about 0-3KHz, can be easily received signals of 7.023MHz beat . 8050 is biased in the non-linear region (the transistor is then two diodes back to back), and the signal received by the antenna BFO signal for mixing, mixing the audio signals obtained through coupling to the 0.1uF capacitor constituted LM386 audio power amplifiers, audio signal amplified by the LM386 5 feet 10uF capacitor blocking evacuation headphones. Key not only control the LM386 power on-off switch is also biased varactor D2, so that volume changes in different states.
4, commissioning
5.1, the former power, then dummy load, to prevent accidents caused by burning emission.
Directly to the 51 ohm dummy load as soldered to the circuit board behind: Q9 or 51 ohm connector and make a dummy load.
5.2, power: power interface, regardless of the polarity (internal already rectified), recommended the use of battery power, you can use a DC 13.8V linear power supply, but the direct conversion radios will supply ripple directly into sound headphones . Power rear portion at a distance from the circuit board, concept of check whether there dislocation caused by the burning of welding smoke is like, if there is power failure timely diagnosis. Tens of seconds after the power on, touch the dummy load, if there is an accident described welding heat emission caused by wrong, if there is power failure timely diagnosis
5.3, listening to the background noise: 8 Op connected through the headset, you will hear background noise of rushing after power, this preliminary note sound amplification part is working properly.
5.4, ??the measured receiving circuit: In the case of all the work before normal start testing the receiving circuit, remove the dummy load, the power to listen to the noise floor, connect the antenna or antennas connected to a long-term core seat, listening to the noise floor, if both sound very different (much larger then the antenna noise floor), the basic instructions properly.
5.5, emission test: connect a dummy load, an access key manually, power. Then click on key will enter the emission state, not the state of current emission will be around 20mA, current emission state will be around 120mA, when the buzzer jumper plug will launch tweet, some time after launch dummy load significant fever is normal. Note that not long continuous emission.