Any receiver covering these frequencies is expensive. You can, with this simple but powerful device, listen to the 7 MHz band, the 40 meters, one of the busiest bands for about 15 €! Suffice to say anything! JP
The receiver is for both the amateur radio veteran who wishes to reconnect with yourself and have a little extra receiver, at beginner wishing to make his debut, and I think particularly for school, which after climbing the "traditional" dimmer third of college classes, want to achieve something much more exciting. This brings me to digress. Indeed, patterns of small receivers are numerous, but often too simple, because unsuitable copied verbatim to each other, and this often leads the beginner to fail. And when mounting poorly or not work at all, the beginner will be disappointed, put it aside, and there touch again. The result will be the opposite of the purpose, it has managed to disgust a young of applied electronics.
Of course, the receiver described here does not claim to avoid failure as a bad soldering or a bad component in the wrong place it also leads, but it has the merit to work perfectly and be the culmination of many tests on different assemblies. We had to put in the place of beginning, and look for the reasons of possible failures. It is therefore imperative to tighten the budget by making maximum use of cheap components and little fragile and finding a provider who will sell them and the printed circuit board, at the right price.
We must also avoid a too tight installation of components reduce the possibility of mounting errors and facilitate any replacements incorrectly mounted components.
And finally, we must propose a montage works (even with a small 9 volt battery ordinary) while being perfectly reproducible whatever types components. 7 MHz receiver scheme. Description The following description is primarily intended for the neophyte. It is perhaps a little scare, but is necessary for understanding the assembly, by cons not essential to its achievement. This description will want in simplistic terms, the seasoned forgive me ... This small receiver is of the "direct conversion", that is to say that the frequency of the receiver's local oscillator is set at low things near the receive frequency. The mixture of these two frequencies gives us signals in the range of "low frequency" signals. Just to amplify these signals while filtering them, to make them audible in headphones or a small speaker. The only drawback of this system compared to a conventional receiver is meant the two sidebands of a signal. But this is only a minor inconvenience, given the simplicity of assembly. In addition, the human ear is able to make a good selection signals. Besides the reception quality will surprise more than one. But look in more detail the receiver of the scheme. The high frequency signal from the antenna through the capacitor C1, which by its low value, aims to reduce the level of very strong signals from the band of small waves. These, especially if you live near one of these issuers could indeed saturate the integrated circuit IC1, which has the effect of per affect motor correct operation of the receiver. Similarly, next to the 40-meter band amateur radio, is a very active broadcasting band, especially at night, with very powerful transmitters, which also could disrupt our receiver. To remedy this, simply decrease the gain with the potentiometer "Pot1" which has the effect of much more effectively reduce the disturbing signal that the signal we want to hear. This then passes through a band pass filter (L1, C2 and CV1) which, as its name suggests, promotes the band that we want to listen, before being applied to the mixer-oscillator circuit NE612 (IC1). It is powered by a stabilized voltage of 5 volts by the voltage regulator circuit 78L05 (IC3). The frequency of the local oscillator is determined by the components C8, C9, CV2, L2 and D1. D1 is a diode "varicap", that is to say, its capacity varies depending on the voltage applied to its terminals. Clearly, we are going to vary this voltage using the potentiometer "Pot2" to explore all band. The potentiometer "Pot3" serving, in turn, fine tuning, allowing to adjust more easily on a signal. This solution was chosen to avoid the purchase of a multi-potentiometer, very expensive, especially for a young person. But back to the useful signal. It was transposed in IC1, low frequency (LF). From 4 and 5 of IC1, it passes through a filter cell BF (C11, R2, C14), whose role is to reduce the high frequencies above 3 kHz, unnecessary and that would make painful. Listening C12 and C13 are capacitors for isolating the DC voltages. The connection between IC1 and BF LM386 amplifier circuit (IC2) is symmetrical, which increases slightly the number of components, but above all the advantage of reducing non signals desirable and, in addition, to increase the gain of the useful signals (6 decibels for connoisseurs ...). The amplifier circuit IC2 has its gain set to maximum (46 dB) by the use of the capacitor C16 (maximum value) . This is necessary for a receiver of this type if you want to enjoy a comfortable listening. R6 and C17 are used to reduce the white noise generated by the large amplification of IC2, this is called a circuit "anti-hiss". R7 and C18 prevent IC2 to enter into oscillation if the impedance of the used speaker is too low. R5 and C15 are there for the same reason, according to the type of battery used. Indeed, some batteries with too low internal resistance IC2 leads to come into oscillation. With this system you can use any battery, even if it is no longer early youth. C19 is an isolation capacitor for the DC voltage present in 5 of IC2. BF, against her by the readily passes through to finally get to the stereo jack J2. Why use a stereo jack? For reasons of course cost. Each home has a Walkman headset, well, it's just the job and its stereo connector. Similarly, many people have a set of speakers for your computer. It works beautifully, and the connector is also stereo. But you can also, if your budget still allows, buy a small speaker of 8 ohms and integrate it to your housing. The diode D2 serves to protect the installation against any inadvertent polarity reversal when connecting the battery. View 7 MHz receiver mounted. Airy for easy assembly but can not be easier! The scale printed circuit 1.Component Diagram implantation. View the inductor L1. Note the 4 turns wound par- over the 22 turns. The establishment of the components will not be a problem. However, as a precaution, integrated circuits are mounted on supports. The finished receiver, ready to move listening.Beautiful sleepless nights ahead! Installation The support is best suited, especially for beginners, the printed circuit . This is available from the vendor quoted in the article. The layout of elements on the circuit is not complicated, just refer to the installation diagram and photographs. For assembly, it is necessary to remember a few helpful tips, success is at this price. Using a soldering iron up to 40 watts with a fine tip. The weld is preferably 60% tin. Carefully check the components, identify and sort (it is easier to weld than desoldering!) Before assembly. Start with the smallest and ending with the largest, which is logical. Provide support for integrated circuits IC1 and IC2 on everything for the NE612, it suppor as badly short circuits between legs. This will make it easy to change after possible dubious manipulations. The chemical capacitors have a sense of mounting it must be observed (+ and -)., Otherwise they can explode at the slightest reversal Pay attention to the mounting integrated circuits, there is a sense, informed about the layout diagram. The potentiometers are mounted directly on the PCB. The chokes are not difficult to achieve (see photo). We must not forget to strip the ends enamelled son after the completion of the coils in order to weld them. Please note that there is no short circuit between the primary and secondary winding of L1. And identify all good connection of two windings (see diagram). The plate may be mounted in a small housing, of any material. Fixing is by making potentiometers or (and) the holes provided. Do not forget to connect the antenna to a coaxial input jack (J1) and BF output to the stereo jack (note the position of the mass son!). The power supply can be done by a small 9 volt battery with its connection clip. It is also possible for more autonomy, connect in series two 4.5 volt flashlight batteries. Add to each of power according to their preferences. Settings To operate the receiver, it will of course have an antenna. For the first tests, a 0.75 mm square sheathed wire (easily found in supermarkets) stretched long by 4 to 5 meters, can already do the trick, although the whole is not very suitable for impedance point of view. Obviously, a longer antenna will give better results, especially if it is tuned to the frequency range receivable (over 10 meters for example). If assembly has been correctly done, the receiver must operate from the first power up.It can be set without measuring device. But first, we must re-check the installation of all components, can not be repeated enough. The integrated circuits IC1 and IC2 have been placed on their last media, taking care to their sense of placement. The settings will preferably day, when the amateur radio traffic is very intense on this band. Avoid night for the first test. Connect the antenna to the receiver. The taut wire can be provided at its end, we will not forget to strip, form, male banana. It is also very well plugged into the coaxial socket SO239. Thereafter, and for best results, we can always connect a worthy antenna that name, with a descent in coaxial cable with the appropriate connector. Connect the headset or speaker in stereo jack, and turn it on. Place CV1 to half capacity. Then P1 and Pot1 fully in the direction of clockwise. Pot2 Pot3 and will be placed halfway. CV2 set very gently with an insulated screwdriver until you hear one or more amateur radio stations by voice or Morse. Then set up CV1 receiving these stations. If the reception is too strong, or disrupted by a broadcast station is heard over the entire reception range, you must decrease the gain with Pot1. Your receiver is ready for the first listening. With Pot2 you search stations to listen to, and you have Pot3 fine tuning to be adjusted effortlessly. The setting "pifométrique" is over and will suit any beginner without measuring instruments. If we want to spread the whole gang, and only the band throughout Pot2 of the race, there must be an RF generator or receiver traffic. The beginner can then visit a ham radio club (there are usually in all regions) and get help. The setting procedure is then very simple and very accurate. Simply connect the antenna input to the generator, set it to 50 microvolts output. Place Pot2 fully in the direction of clockwise, the generator on 7100 kilohertz and seek signal CV2. Then Pot2 in the opposite direction, the generator on 7000 kilohertz, look for the signal with P1. The generator on 7,050 kHz, set CV1 maximum signal. Your receiver is now perfectly adjusted. If there is no generator and you can access a traffic receiver, the settings will be just as simple. Connect together the two antenna inputs of the two receivers. Proceed as above, except that this time you will hear the signal of the local oscillator of your small receiver in traffic receiver tuned to the frequencies named above. Your little receiver is now finished, and it will allow you to familiarize yourself with the amateur world, while having learned to make from A to Z. We hope that it serves as a springboard for future achievements and maybe it helps to encourage vocations. List of components R7: .. ..... 10 ½R5: ....... 100 ½ R2: ....... 1.5 k½ R1: ....... 10 k½ R3: ...... .10 k½ R4: ....... 10 k½ R6: ....... 10 k½ All resistors are 1/4 watt C1: ....... 47 pF C8: .. ..... 56 pF ceramic coefficient. zero temperatureC5: ....... 100 pF C6: ....... 100 pF C9: ....... 150 pF ceramic coefficient. zero temperature or polystyrene C2: ...... 220 pF C7: ...... 1 nF C3: ...... 1 nF C17: .... 10 nF C11: 47 .... nF C14: .... 47 nF C10: .... 100 nF C12: .... 100 nF C13: .... 100 nF C18: .... 100 nF C4: ...... 220 nF C16: .... 10 uF C19: .... 47 uF C15: .... 100 uF / 25 volts CV1: .... 60 pF Adjustable CV2: .... 60 pF Adjustable IC1: .. ... NE612 IC2: ..... LM386 IC3: ..... 78L05 D1: ...... BB909A D2: ...... 1N4001P1: ....... 22 adjustable k½ Flat Pot1: .... 1 k½ linear (gain) Pot2: .... 10 ½ k linear (frequency)Pot3: .... 500 ½ (variable) L1: ....... 22 turns 0.5 mm enameled wire toroid T37-2 +4 same wire windings coiled over the 22 turns L2: ....... 22 same wire coils J1: ....... coaxial base SO239 or other J2: ....... stereo mini jack female for chassis 2 .......... ICs supports DIL8 1 .......... battery clip for connection 1 ... ....... simple switch ...... 56 pF ceramic coefficient. zero temperature C5: ....... 100 pF C6: ....... 100 pF C9: ....... 150 pF ceramic coefficient. zero temperature or polystyrene C2: ...... 220 pF C7: ...... 1 nF C3: ...... 1 nF C17: .... 10 nF C11: 47 .... nF C14: .... 47 nF C10: .... 100 nF C12: .... 100 nF C13: .... 100 nF C18: .... 100 nF C4: ...... 220 nF C16: .... 10 uF C19: .... 47 uF C15: .... 100 uF / 25 volts CV1: .... 60 pF Adjustable CV2: .... 60 pF Adjustable IC1: .. ... NE612 IC2: ..... LM386 IC3: ..... 78L05 D1: ...... BB909A D2: ...... 1N4001P1: ....... 22 adjustable k½ Flat Pot1: .... 1 k½ linear (gain) Pot2: .... 10 ½ k linear (frequency)Pot3: .... 500 ½ (variable) L1: ....... 22 turns 0.5 mm enameled wire toroid T37-2 +4 same wire windings coiled over the 22 turns L2: ....... 22 same wire coils J1: ....... coaxial base SO239 or other J2: ....... stereo mini jack female for chassis 2 .......... ICs supports DIL8 1 .......... battery clip for connection 1 ... ....... simple switch ...... 56 pF ceramic coefficient. zero temperature C5: ....... 100 pF C6: ....... 100 pF C9: ....... 150 pF ceramic coefficient. zero temperature or polystyrene C2: ...... 220 pF C7: ...... 1 nF C3: ...... 1 nF C17: .... 10 nF C11: 47 .... nF C14: .... 47 nF C10: .... 100 nF C12: .... 100 nF C13: .... 100 nF C18: .... 100 nF C4: ...... 220 nF C16: .... 10 uF C19: .... 47 uF C15: .... 100 uF / 25 volts CV1: .... 60 pF Adjustable CV2: .... 60 pF Adjustable IC1: .. ... NE612 IC2: ..... LM386 IC3: ..... 78L05 D1: ...... BB909A D2: ...... 1N4001P1: ....... 22 adjustable k½ Flat Pot1: .... 1 k½ linear (gain) Pot2: .... 10 ½ k linear (frequency)Pot3: .... 500 ½ (variable) L1: ....... 22 turns 0.5 mm enameled wire toroid T37-2 +4 same wire windings coiled over the 22 turns L2: ....... 22 same wire coils J1: ....... coaxial base SO239 or other J2: ....... stereo mini jack female for chassis 2 .......... ICs supports DIL8 1 .......... battery clip for connection 1 ... ....... simple switch
The receiver is for both the amateur radio veteran who wishes to reconnect with yourself and have a little extra receiver, at beginner wishing to make his debut, and I think particularly for school, which after climbing the "traditional" dimmer third of college classes, want to achieve something much more exciting. This brings me to digress. Indeed, patterns of small receivers are numerous, but often too simple, because unsuitable copied verbatim to each other, and this often leads the beginner to fail. And when mounting poorly or not work at all, the beginner will be disappointed, put it aside, and there touch again. The result will be the opposite of the purpose, it has managed to disgust a young of applied electronics.
Of course, the receiver described here does not claim to avoid failure as a bad soldering or a bad component in the wrong place it also leads, but it has the merit to work perfectly and be the culmination of many tests on different assemblies. We had to put in the place of beginning, and look for the reasons of possible failures. It is therefore imperative to tighten the budget by making maximum use of cheap components and little fragile and finding a provider who will sell them and the printed circuit board, at the right price.
We must also avoid a too tight installation of components reduce the possibility of mounting errors and facilitate any replacements incorrectly mounted components.
And finally, we must propose a montage works (even with a small 9 volt battery ordinary) while being perfectly reproducible whatever types components. 7 MHz receiver scheme. Description The following description is primarily intended for the neophyte. It is perhaps a little scare, but is necessary for understanding the assembly, by cons not essential to its achievement. This description will want in simplistic terms, the seasoned forgive me ... This small receiver is of the "direct conversion", that is to say that the frequency of the receiver's local oscillator is set at low things near the receive frequency. The mixture of these two frequencies gives us signals in the range of "low frequency" signals. Just to amplify these signals while filtering them, to make them audible in headphones or a small speaker. The only drawback of this system compared to a conventional receiver is meant the two sidebands of a signal. But this is only a minor inconvenience, given the simplicity of assembly. In addition, the human ear is able to make a good selection signals. Besides the reception quality will surprise more than one. But look in more detail the receiver of the scheme. The high frequency signal from the antenna through the capacitor C1, which by its low value, aims to reduce the level of very strong signals from the band of small waves. These, especially if you live near one of these issuers could indeed saturate the integrated circuit IC1, which has the effect of per affect motor correct operation of the receiver. Similarly, next to the 40-meter band amateur radio, is a very active broadcasting band, especially at night, with very powerful transmitters, which also could disrupt our receiver. To remedy this, simply decrease the gain with the potentiometer "Pot1" which has the effect of much more effectively reduce the disturbing signal that the signal we want to hear. This then passes through a band pass filter (L1, C2 and CV1) which, as its name suggests, promotes the band that we want to listen, before being applied to the mixer-oscillator circuit NE612 (IC1). It is powered by a stabilized voltage of 5 volts by the voltage regulator circuit 78L05 (IC3). The frequency of the local oscillator is determined by the components C8, C9, CV2, L2 and D1. D1 is a diode "varicap", that is to say, its capacity varies depending on the voltage applied to its terminals. Clearly, we are going to vary this voltage using the potentiometer "Pot2" to explore all band. The potentiometer "Pot3" serving, in turn, fine tuning, allowing to adjust more easily on a signal. This solution was chosen to avoid the purchase of a multi-potentiometer, very expensive, especially for a young person. But back to the useful signal. It was transposed in IC1, low frequency (LF). From 4 and 5 of IC1, it passes through a filter cell BF (C11, R2, C14), whose role is to reduce the high frequencies above 3 kHz, unnecessary and that would make painful. Listening C12 and C13 are capacitors for isolating the DC voltages. The connection between IC1 and BF LM386 amplifier circuit (IC2) is symmetrical, which increases slightly the number of components, but above all the advantage of reducing non signals desirable and, in addition, to increase the gain of the useful signals (6 decibels for connoisseurs ...). The amplifier circuit IC2 has its gain set to maximum (46 dB) by the use of the capacitor C16 (maximum value) . This is necessary for a receiver of this type if you want to enjoy a comfortable listening. R6 and C17 are used to reduce the white noise generated by the large amplification of IC2, this is called a circuit "anti-hiss". R7 and C18 prevent IC2 to enter into oscillation if the impedance of the used speaker is too low. R5 and C15 are there for the same reason, according to the type of battery used. Indeed, some batteries with too low internal resistance IC2 leads to come into oscillation. With this system you can use any battery, even if it is no longer early youth. C19 is an isolation capacitor for the DC voltage present in 5 of IC2. BF, against her by the readily passes through to finally get to the stereo jack J2. Why use a stereo jack? For reasons of course cost. Each home has a Walkman headset, well, it's just the job and its stereo connector. Similarly, many people have a set of speakers for your computer. It works beautifully, and the connector is also stereo. But you can also, if your budget still allows, buy a small speaker of 8 ohms and integrate it to your housing. The diode D2 serves to protect the installation against any inadvertent polarity reversal when connecting the battery. View 7 MHz receiver mounted. Airy for easy assembly but can not be easier! The scale printed circuit 1.Component Diagram implantation. View the inductor L1. Note the 4 turns wound par- over the 22 turns. The establishment of the components will not be a problem. However, as a precaution, integrated circuits are mounted on supports. The finished receiver, ready to move listening.Beautiful sleepless nights ahead! Installation The support is best suited, especially for beginners, the printed circuit . This is available from the vendor quoted in the article. The layout of elements on the circuit is not complicated, just refer to the installation diagram and photographs. For assembly, it is necessary to remember a few helpful tips, success is at this price. Using a soldering iron up to 40 watts with a fine tip. The weld is preferably 60% tin. Carefully check the components, identify and sort (it is easier to weld than desoldering!) Before assembly. Start with the smallest and ending with the largest, which is logical. Provide support for integrated circuits IC1 and IC2 on everything for the NE612, it suppor as badly short circuits between legs. This will make it easy to change after possible dubious manipulations. The chemical capacitors have a sense of mounting it must be observed (+ and -)., Otherwise they can explode at the slightest reversal Pay attention to the mounting integrated circuits, there is a sense, informed about the layout diagram. The potentiometers are mounted directly on the PCB. The chokes are not difficult to achieve (see photo). We must not forget to strip the ends enamelled son after the completion of the coils in order to weld them. Please note that there is no short circuit between the primary and secondary winding of L1. And identify all good connection of two windings (see diagram). The plate may be mounted in a small housing, of any material. Fixing is by making potentiometers or (and) the holes provided. Do not forget to connect the antenna to a coaxial input jack (J1) and BF output to the stereo jack (note the position of the mass son!). The power supply can be done by a small 9 volt battery with its connection clip. It is also possible for more autonomy, connect in series two 4.5 volt flashlight batteries. Add to each of power according to their preferences. Settings To operate the receiver, it will of course have an antenna. For the first tests, a 0.75 mm square sheathed wire (easily found in supermarkets) stretched long by 4 to 5 meters, can already do the trick, although the whole is not very suitable for impedance point of view. Obviously, a longer antenna will give better results, especially if it is tuned to the frequency range receivable (over 10 meters for example). If assembly has been correctly done, the receiver must operate from the first power up.It can be set without measuring device. But first, we must re-check the installation of all components, can not be repeated enough. The integrated circuits IC1 and IC2 have been placed on their last media, taking care to their sense of placement. The settings will preferably day, when the amateur radio traffic is very intense on this band. Avoid night for the first test. Connect the antenna to the receiver. The taut wire can be provided at its end, we will not forget to strip, form, male banana. It is also very well plugged into the coaxial socket SO239. Thereafter, and for best results, we can always connect a worthy antenna that name, with a descent in coaxial cable with the appropriate connector. Connect the headset or speaker in stereo jack, and turn it on. Place CV1 to half capacity. Then P1 and Pot1 fully in the direction of clockwise. Pot2 Pot3 and will be placed halfway. CV2 set very gently with an insulated screwdriver until you hear one or more amateur radio stations by voice or Morse. Then set up CV1 receiving these stations. If the reception is too strong, or disrupted by a broadcast station is heard over the entire reception range, you must decrease the gain with Pot1. Your receiver is ready for the first listening. With Pot2 you search stations to listen to, and you have Pot3 fine tuning to be adjusted effortlessly. The setting "pifométrique" is over and will suit any beginner without measuring instruments. If we want to spread the whole gang, and only the band throughout Pot2 of the race, there must be an RF generator or receiver traffic. The beginner can then visit a ham radio club (there are usually in all regions) and get help. The setting procedure is then very simple and very accurate. Simply connect the antenna input to the generator, set it to 50 microvolts output. Place Pot2 fully in the direction of clockwise, the generator on 7100 kilohertz and seek signal CV2. Then Pot2 in the opposite direction, the generator on 7000 kilohertz, look for the signal with P1. The generator on 7,050 kHz, set CV1 maximum signal. Your receiver is now perfectly adjusted. If there is no generator and you can access a traffic receiver, the settings will be just as simple. Connect together the two antenna inputs of the two receivers. Proceed as above, except that this time you will hear the signal of the local oscillator of your small receiver in traffic receiver tuned to the frequencies named above. Your little receiver is now finished, and it will allow you to familiarize yourself with the amateur world, while having learned to make from A to Z. We hope that it serves as a springboard for future achievements and maybe it helps to encourage vocations. List of components R7: .. ..... 10 ½R5: ....... 100 ½ R2: ....... 1.5 k½ R1: ....... 10 k½ R3: ...... .10 k½ R4: ....... 10 k½ R6: ....... 10 k½ All resistors are 1/4 watt C1: ....... 47 pF C8: .. ..... 56 pF ceramic coefficient. zero temperatureC5: ....... 100 pF C6: ....... 100 pF C9: ....... 150 pF ceramic coefficient. zero temperature or polystyrene C2: ...... 220 pF C7: ...... 1 nF C3: ...... 1 nF C17: .... 10 nF C11: 47 .... nF C14: .... 47 nF C10: .... 100 nF C12: .... 100 nF C13: .... 100 nF C18: .... 100 nF C4: ...... 220 nF C16: .... 10 uF C19: .... 47 uF C15: .... 100 uF / 25 volts CV1: .... 60 pF Adjustable CV2: .... 60 pF Adjustable IC1: .. ... NE612 IC2: ..... LM386 IC3: ..... 78L05 D1: ...... BB909A D2: ...... 1N4001P1: ....... 22 adjustable k½ Flat Pot1: .... 1 k½ linear (gain) Pot2: .... 10 ½ k linear (frequency)Pot3: .... 500 ½ (variable) L1: ....... 22 turns 0.5 mm enameled wire toroid T37-2 +4 same wire windings coiled over the 22 turns L2: ....... 22 same wire coils J1: ....... coaxial base SO239 or other J2: ....... stereo mini jack female for chassis 2 .......... ICs supports DIL8 1 .......... battery clip for connection 1 ... ....... simple switch ...... 56 pF ceramic coefficient. zero temperature C5: ....... 100 pF C6: ....... 100 pF C9: ....... 150 pF ceramic coefficient. zero temperature or polystyrene C2: ...... 220 pF C7: ...... 1 nF C3: ...... 1 nF C17: .... 10 nF C11: 47 .... nF C14: .... 47 nF C10: .... 100 nF C12: .... 100 nF C13: .... 100 nF C18: .... 100 nF C4: ...... 220 nF C16: .... 10 uF C19: .... 47 uF C15: .... 100 uF / 25 volts CV1: .... 60 pF Adjustable CV2: .... 60 pF Adjustable IC1: .. ... NE612 IC2: ..... LM386 IC3: ..... 78L05 D1: ...... BB909A D2: ...... 1N4001P1: ....... 22 adjustable k½ Flat Pot1: .... 1 k½ linear (gain) Pot2: .... 10 ½ k linear (frequency)Pot3: .... 500 ½ (variable) L1: ....... 22 turns 0.5 mm enameled wire toroid T37-2 +4 same wire windings coiled over the 22 turns L2: ....... 22 same wire coils J1: ....... coaxial base SO239 or other J2: ....... stereo mini jack female for chassis 2 .......... ICs supports DIL8 1 .......... battery clip for connection 1 ... ....... simple switch ...... 56 pF ceramic coefficient. zero temperature C5: ....... 100 pF C6: ....... 100 pF C9: ....... 150 pF ceramic coefficient. zero temperature or polystyrene C2: ...... 220 pF C7: ...... 1 nF C3: ...... 1 nF C17: .... 10 nF C11: 47 .... nF C14: .... 47 nF C10: .... 100 nF C12: .... 100 nF C13: .... 100 nF C18: .... 100 nF C4: ...... 220 nF C16: .... 10 uF C19: .... 47 uF C15: .... 100 uF / 25 volts CV1: .... 60 pF Adjustable CV2: .... 60 pF Adjustable IC1: .. ... NE612 IC2: ..... LM386 IC3: ..... 78L05 D1: ...... BB909A D2: ...... 1N4001P1: ....... 22 adjustable k½ Flat Pot1: .... 1 k½ linear (gain) Pot2: .... 10 ½ k linear (frequency)Pot3: .... 500 ½ (variable) L1: ....... 22 turns 0.5 mm enameled wire toroid T37-2 +4 same wire windings coiled over the 22 turns L2: ....... 22 same wire coils J1: ....... coaxial base SO239 or other J2: ....... stereo mini jack female for chassis 2 .......... ICs supports DIL8 1 .......... battery clip for connection 1 ... ....... simple switch