Shuangkuang radio
ore radio today, we are used to refer to those radios that do not use power and only have one semiconctor component in the circuit as "ore radio"“ "Ore radio" originated from the early geophone element, which was made directly from natural ore. when it was used, it had to adjust its pressure and orientation on the ore through a metal probe. Ore radio is the simplest of all radio receiving equipment. Unless it is quite close to the radio station, the erection of its antenna and ground wire is very elegant
ore radio is a kind of passive radio without amplification circuit, which is composed of antenna, ground wire, basic tuning circuit and ore detector. It is the simplest radio receiving device, mainly used for the reception of medium wave public radio. It was originally made of ore, so it got its name
when the transistor was invented, radio enthusiasts used germanium diodes instead of minerals. China's old radio enthusiasts who have played ore machine should remember 2ap9, a diode model full of nostalgia
a simple ore radio can be composed of only one coil, variable capacitor, geophone and earphone. Because it has only one tuning loop, it is called "single loop ore radio". Such a machine can accept local or distant radio stations when it is equipped with good ground and sky lines, but the ability (selectivity) of separating radio stations is very poor, There is often a "clip", that is, two or more radio stations ring together
in addition to this simple form, there can also be two or even three loop ore radio to improve the selectivity, but there is no big improvement in the volume. Now there is also a new type of MOSFET for detection, which can obtain a voltage drop close to 0 V. this kind of element has excellent detection effect for ore radio< Excellent ore radio needs: excellent ground wire, high Q value coil and variable capacitance, detector with low forward voltage drop, sensitive earphone with good impedance matching
2. The broadcast can still be heard in case of power failure or no battery
3. It can be used to test the efficiency of antenna or ground wire
4. Ore machine is very attractive and can be used to guide beginners and children into the world of radio, radio and DIY
5. The circuit is simple and easy to make
6. Connect the power amplifier to receive the AM broadcast with the best sound quality
7. It can be used for life without maintenance cost.
1: one PVC pipe with 100 mm diameter and proper length, and several enameled wires with 0.8-1 mm diameter
2: one air plex transformer, 365p × 2
1 3:2ap9 wave building diode (obtained by dismantling the old semiconctor)
1 4:220v / 10V small power transformer, for impedance conversion, 8 Ω One horn loudspeaker<
fabrication method:
two groups of coils are tightly wound on the outside of PVC pipe, the turns are 65, the primary and secondary are tapped 40 turns away from the ground, the primary tap is connected to the antenna, and the secondary tap is connected to the positive pole of detection diode. The output of the diode and the ground are connected to the 220 V end of the power transformer, and the low-voltage end of the transformer is connected to the loudspeaker. The antenna should be as long as possible, and the ground wire must be buried underground
next, turn the air plex to hear the broadcast.
If you can make sure that the tuning part of your single circuit ore machine is normal, but you can't separate the adjacent radio stations, you can improve the receiving effect of your ore machine according to your actual situation
the most important thing to improve the selectivity of ore machine is to make the on load Q value of your ore machine tuning circuit as high as possible, but the improvement of on load q is limited by many factors
firstly, you need to obtain the tuning coil with high load Q value, and then the harmonic capacitor with high Q value, which is the premise
next, you need to improve the sensitivity of your headset as much as possible, which can rece the energy extracted from the resonant circuit, rece the burden of the resonant circuit, and effectively improve the effective Q value of the resonant circuit
also, you can make efforts to improve the circuit. In the single circuit mode, you can try the 75 ｛ ore machine circuit of the famous ore machine bull old Dave; For multi loop, the hifi al loop ore machine circuit, which is highly praised by many people before, can be used (some people use the output signal of this circuit to drive the high fidelity sound system, which is said to have achieved good results)
circuit example of inctive ore machine with 75 circuit
The top ten radio brands are: Desheng, Jinye, Philips, Anjian, panda, Sanyo, Sony, Kailong, Hershey DA and Dejin
Hershey radio integrates proct R & D, design, proction and sales. Hershey radio adopts domestic advanced technology for proction, with rigorous and meticulous proction process and long service life
Dejin, the radio is made of imported materials, no howling, no noise, clear sound, very practical, with permanent storage of 268 radio stations