Basic Indicators Power: 7V-12V (Recommended 9V Stacking Battery) Circuit Board: 56mm x 41 MM Antenna: 50 ohm, unbalanced, BNC / Q9 interface vibration leak: about 1MW (50 ohm) frequency range: 7.060-7.064MHz (7.060M crystal series 50p fine-tuning capacitor) Receive: Current: less than 10mA (9V power) Headphones: low-resistance earphones (recommended Sony, AIWA, etc. High-sensitive Walkman headphones)
Launch: Power: about 200MW current: about 50mA (9V power) spurious (harmonic) inhibition: -20db
Subjective evaluation is poorly sensitive and selective, which is easy to be broadcast interference (BCI). The frequency stability is good, and the SSB signal can be accepted. Circuit is low. The switch is large when transceiving and switching, and it is easy to cause the wrong code.
Introduction to the circuit, see Figures 1, Q1 and the surrounding element constitute a typical Cipiptite oscillator and remain oscillated (so there is a left and right oscillation signal leakage at reception), the signal is directly coupled to Q2 through the 82PF capacitance, in the transmit state ( Pressing the electric key), Q2 is used as Class C power, the amplified signal is coupled to the π-type low pass filter by 0.01uF capacitance, and then send antenna emission; in the receiving state (the electric button is released), Q1 and the surrounding element constitute a difference Oscillator (BFO), Q2 is biased in a non-linear area (which can be so much, the triode is nothing more than the two diodes that are back to the back!), Mix the signal received by the antenna with the signal of BFO, mixed audio The signal is coupled to the Audio power amplifier configured to LM386 by a 0.1uf capacitor, and the amplified audio signal is separated from the 10uf capacitor by the 10uf capacitor. The electric terminal not only controls the disconnection of the LM386 power supply, but also switches the bias of Q2, so that it works in a different state. Figure 1 "Leather shoes" 200MW micro power] radial report receiving letter electrical schematic
Component selection
All inductors select a roll-lowering inductance, where L3 uses 2.2uh when 80 m bands. C6 and C7 use 820pf when 80 m bands. Three-pole Q1 and Q2 do not have strict regulations, and the magnification of silicon NPN triodes between 100 to 200 can be used normally. For example, 9011, 9013, 9018, 8050, 2 N2222A, 2N3904, etc., recommend Q1 and Q2 are 9013 or Use 2N3904. Crystals need to be based on fundamental frequency crystals, 7.060m, and 7.042m crystals are available in the antenna. Subtocks are recommended to use sockets on the circuit board and L3, C7 to switch band or frequencies. For example, in order to increase the transmit power, a 12V power source can be used, but the C10 is required to 100U.
Debug method
Welding end should check if there is a short circuit, if there is no, add a 9V stacking battery, connect the headset, do not pick an antenna, normal conditions should hear the tiny "Shasha" sound, connect the antenna noise increase or you can hear some signal The whole motor is below 10 mA. If you hear a lot of whistling or current, the circuit is self-excited, the solution is to pick up a 103 porcelain capacitor on both ends of "Speaker". If it is invalid, then at both ends of the 10UF capacitor of the LM386 power supply and connected A 103 porcelain capacitor, if it is still invalid, at the 9V supply input and one 103 porcelain capacitor. The reception should be basically normal. Figure 2 Schematic diagram of high frequency power meter circuit with 1W 50 ohms
Then, the high-frequency power table with a fake load (Figure 2 shows the reference circuit diagram), shorts the "Key" end, and the headphones should be quickly silent, and the high-frequency power table has a certain output. The emitting machine current is 40-100mA. Put a short-wave / medium wave radio at the next to 0.5 meters, check all the received frequency ranges, in addition to the carrier frequency and frequency, the signals generated by "leather shoes" should not be heard. If there is any other signal (especially whistling), there is a high frequency self-excited. Cutting the power cord between Q1 and Q2, with a 100UH inductance and 100 ohm resistor, and then connect in series to effectively eliminate high frequency self-excitement. The Schedule gives the DC reference voltage of each major element in the launch and receiving state.
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