Frog QRP Kit , the 40 meter band micro-power transceiver 7.023 MHz
Nel campo dei radioamatori, di solito non più di 5W è conosciuto come comunicazioni a bassa potenza, o comunicazione QRP. Il QRP è un importante ramo radioamatoriale. Molti appassionati di comunicazione QRP sono allo stesso tempo appassionati di apparecchiature QRP autocostruite.
"Frog" Ultimate Edition, after a long-term verification to fine-tune the upgrade, change the details listed below, for a user puts forward, thanks.
1, key interface, right to left, with key interface.
2, increase the power indicator light, in time for fault judgment.
3, change the isolation switch structure, eliminate the transmitting and receiving "impact noise Kaka", and solve the high-frequency switch easily affected by impact damage, is not easy to buy problems, proposed solutions.
4, the power supply interface and an antenna interface using the interface costs higher, relative to white 2.54 simple interface more durable, prevent leakage of copper to make the interface circuit board burn condition.
5, the circuit board to increase the grounding strip, easier to debug, with shell.
6, optimize the transmitting circuit, enhance the transmit power to the 3W (12V supply).
This kit welding of electronic technology basis, will recognize device, welding, induction machine without debugging, as long as careful discrete parts manual assembly can be successful. If the new welding error condition, built the first not to handle, please contact customer service, can obtain the corresponding technical guidance.
"Frogs" miniature telegraph transceiver package instructions Ultimate Edition
A brief introduction
This is a very small volume of a simple 40 meter band micro-power amplitude telegraph transceiver, 9V square battery or external 9-12V DC power supply. Spread good time, and the nearby provinces hundreds of kilometers amateur radio communications. This machine was first introduced by domestic radio enthusiasts, but also it played a nice name "frogs". The frogs calling Kit 3.1 public version based, combined with the actual usage Fixed several key issues, after several debugging before the formation of the current version.
Key Indicators
Power supply: 9V-12V (Recommended 12V linear regulated power supply)
Antenna: 50 ohm, unbalanced
Transmission power: 2W (9V Power), 3W (12 power)
Frequency: transmitter local oscillator frequency: 7023KHz; receive local oscillator frequency: about 7023-7026KHz
Operating mode: CW
Circuit schematic
See last page of this document accompanying drawings, the receiving part of the core is an NE602, including its internal oscillation circuit and a balanced mixer the antenna signal coming into the mixer after a crystal filter and attenuation potentiometer, The oscillation circuit in the reception frequency oscillation, the two signals after the mixer, directly at the SSB / CW signal is converted to an audio output audio NE602 gave LM386 zoom back, thus completing the whole process. By direct mixing the RF signal into audio receiver is called the "DC receiver, the DC mean direct conversion.
LM386 amplifies the output speech signal, by the 2N7000 FET constituting the mute circuit is used to turn off the receiver in the time when transmitting, at the same time the 74HC00 which the audio oscillator generating sidetone, to make with headset Follow produce drops pattered keying the audio .
Emitting portion using NE602 oscillation circuit, then buffer amplifier 9018, and 9018 as a transmission key, the control transceiver circuit and the signal switching, the final stage is constituted by the D882 Class C amplifier, the amplified high-frequency signal through the LPF filtering followed antenna.
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Component selection
9018 magnification select 130 D882 of about 200 magnification selection. L4 is a high-frequency choke on FT37-43 ferrite bead (black) 0.51mm enameled wire around 11 laps, approximately 20cm (can also be used the fixed inductor instead) for sale on the market, the inductance of about 20uH . L5 is a high-frequency filter inductor 0.51mm enameled wire or mesh wire wound on a magnetic iron core T37-2 (red), 16 laps, about 25cm, the inductance in 1uH about. Other Inductance: 1mH fixed color ring inductance 100mH inductance the cylinder fixed inductors, outsourcing black heat shrink tubing. Less than 1000pF capacitor for high frequency ceramic the 0.47uF capacitor for monolithic capacitors, larger than 1uF capacitor aluminum electrolytic capacitors, all resistance fixed resistor 1/4W 5%.
Production testing
Install all components, first of all transistors, resistors, capacitors with a multimeter test again. Then control the logo to install all the components of the circuit diagram and PCB board. Generally installed in accordance with the order from low to high. After welding, must check for solder short circuit. Package MOS FET 2N7000, in order to prevent electrostatic breakdown, soldering iron should be properly grounded or disconnect the power to the soldering iron, waste heat welding. Integrated circuit mounted socket, which can effectively avoid the core of the integrated circuit welding bad.
Everything is in order, check and correct the positive and negative polarity connected to the power supply, the power supply must not pick the wrong. Inserted into the headphone jack, Walkman headphones, you can hear white noise. On the termination of the antenna 51 ohm resistor false load, shorted KEY (to simulate pressing the key), detection machine current should not exceed 150mA. Not a long shorted KEY launch, otherwise D882 and dummy load fever, accidentally damage.
Termination on the antenna, the antenna should be able to hear the noise gets louder or CW signal, rotating board is indeed 47K potentiometer CW signal tone should change from high to low.
Use
This machine is a simple direct conversion transceiver interference, selectivity can be compared and the superheterodyne receiver, it is necessary to use not worse than the length of a half-wave dipole antenna, or communication is relatively poor. The selection disturbance is relatively small, spread the good opportunity for communication experiment, it is best to make an appointment with your friends communication. Communication distance of about 150-300 km more secure, to greater distance depends on the propagation environment and the operator's operating skills. If the broadcast interference is relatively large, use 5K GAIN potentiometer signal attenuation, emergent signal from the radio interference. Attenuation potentiometer is critical, carefully adjusted, you will receive an unexpected effect. In the dissemination of good times with of this machine FT80C goods shortwave radio with a signal on a distant contrast reception, this local effect is no difference between basic commodity machine, which makes unexpected.
Recommendations for improvement
1N4001 replaced by appropriate varactor tube (recommended the 0P-100P), can increase the receive frequency range. Q1 9018 power between 0.8W ~ 1.2W 8050 power between 1.5W to 2W (select 8050 will make D882
In a critical state, need to be careful).
Finally, I hope you DIY machine, can be a successful!
Faq:
Q: communication distance can be far?
A: shortwave communication distance depends largely on the antenna selection, and the use of small power station must choose good weather conditions, many expert using the classic radio had hundreds of kilometers of joint performance. Radio component of this shop are through the detection apparatus, device purchase volume so can guarantee authentic, key device also after sampling, the output power of a good. So as long as the antenna resonance your good, there will be a good communication distance.
Q: beginners should start from where?
A: the first step: the correct welding welding finished,
The second step: listening, practice to understand the air code,
The third step: the practice of generating code technology own,
The fourth step: make the antenna, the best conditions to buy two sets of spontaneous self test,
The fifth step: and the rest of the world.
Q: the telegraph can talk?
The A:CW transceiver can't talk, only supports SSB or FM modulation machines can talk? Transceiver can only use the key and the earphone receiving message.
Q: suite of difficult assembly?
A: a necessary premise is can recognize device, welding, induction machine without debugging, as long as careful according to kit instructions assembly can be successful. If the new welding error condition, built the first not to handle, please contact customer service, can obtain the corresponding technical guidance.
Q: the use of antenna what kind?
A: this shop will provide a few simple antenna tutorial.
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