Frame scheme for 430 MHz. Radiatetric structures Sale of radio equipment. Production of printed circuit board

For the scheme "Superderegular receiver for 90 ... 150 MHz"

Radio receivers Therapist on 90 ... 150 MHzl1 - 2 turns, L2 - 4 vitakan frame with a diameter of 8 mm, with a wire of 0.8. The scene contains 60 turns of the wire of PAL 0.1 on the MLT 0.5 resistor 0.5. Transferred condensers with air dielectric. - Consormer from a pocket radio. Montazh on "Pyatadki" according to the method of Jurtyeva. ("73 Magazine", Feb.1974, P.100) ...

For the schema "Receiver on the TDA7000 chip (174xa42)"

Radio receipt at the microcircuit\u003e TDA7000 (174XA42) /IMG/TDA7000.Gifdiapoupon of the circuit rate of 1.5-150 MHz. In parentheses, the ratings of capacitors for narrowband FM are indicated (while the 3rd leg of the chip can be left free). pCB From the side of the conductor of the printed circuit board from the side of elements: 1. K174HA42 - Single-chip FM receiver. Radio N 1 1997. Solidary FM receivers. Radio N 2 199733. Radio devices on the K174H42A chip. Radio N 5 1997 ....

For the scheme "Superderegular receiver at 144 MHz"

Radio Receiver to 144 MFs lower scheme ultra-generrative receiver can work like component A simple portable radio station for a range of 144 MHz. Scheme Pretty simple and features has no. The sensitivity of the receiver is approximately 10 ... 15 μV. Constructive scheme Made on the printed circuit board. Unfortunately, the picture of the printed circuit board after its assembly has no preserved (NB). The driver L1 contains 3 "silver" with a diameter of 0.8 mm, frameless - on the mandrel with a diameter of 6 mm, the winding length is 4 mm. DR1 is standard 25 μg. OD2 contains 250 turns of the wire of the PEV 0.1 on the ferrite ring H1000 with a diameter of 8 mm. Transistor Tr - the outlet from the transistor radio, if high-resistant phones apply, then it is not needed. Transistors preferably apply more modern ....

For the scheme "Experimental detector VHF-microwave receivers"

Radio receivers Experimental detector VHF-microwave receiving testEnter on the range of 100-200 MHz Scheme The receiver, shown in Fig. 1, uses a custom line in the housing, paved from copper or fooling fiberglass. The L2 coil contains 4 contemporary wires. The inner diameter of the coil is 12 mm, the winding length is 12 mm. The removal is produced from the middle. The coil L1 is executed in the form of one turn over L2. CONDER C2 is made from a copper plate with a size of 25x50 mm with a Teflon gasket with a thickness of 0.125 mm. You can apply the usual supporting HF capacitor. Receiver It is useful when setting up the microwave hardware as a waveer. The UA3ZNW turnover has turned the same in direct transformation (Fig. 2). Capacitor C2 - the side of the two-way glassstolite from which the resonator was performed. SIMISTOR TS112 and schemes on it when using heteroodine and unch from the book V.Polarkova "Receive Receivers for Amateur Communications" (M.Dosaaf 1981, p.64) This ensured a significantly best reception than the specified article with a two-strangistory UHF on the field transistors KP303! Gometerodine was assembled on the wall of the resonator. For

For the scheme "VHF receiver with a World Cup on a specialized microspectorate KHA058"

For the Scheme "Direct Transform Receiver"

For the scheme "Simple KB receiver"

For the scheme "Simple-BBB World Cup Receiver"

For the "Hijack Indicator" scheme

The proposed device consists of a miniature VHF transmitter, which is powered by rechargeable battery, and a World Cup with a console in the apartment of the owner of the car. The miniature transmitter (Fig. 1) is installed in front of the car parking at night in such a place so that it does not immediately find a hijacker. The CM receiver can be made by any known scheme or to use an industrial, having a VHF range. When the transmitter emits and dwells in the "radio abuse" of the receiver, the latter disappears at the output, and the VT2 transistor (Fig.2) is closed, since At the output of the FM receiver there is no signal and voltage on secondary winding There is no transformer T1. The VT1 transistor is open, the relay K1 is turned on. When the car moves to a few meters, the power of the VHF transmitter becomes insufficient to trigger the occurrence of the receiver, which leads to noise. At the output of the T1 transformer, an alternating voltage appears, which is straightened by the VD1 diode and the filter C8 condenser. VT1 opens, the relay K1 turns off and normally open contacts includes sound alarm. If the hijacker detected the VHF transmitter and disconnect the power, the sound signal will still give any equal. Yakovlev, Nizhnevartovsk ...

The first of them is a transmitter, and the second is the receiver, and they are intended to build the radioline exchange of digital data into the VHF range at a frequency of 433.92 MHz.

These chips can be used not only by direct purpose, but also for constructing low-power amateur transceivers with a fixed frequency in the range of 430 MHz. The resulting device will communicate on small distances (hundreds of meters) and come in handy for walking, rest, etc.

The scheme of the proposed transceiver is shown in Fig. 1. The transmitting part is assembled on the DA1 TX5000 chip, as well as VT3 transistors (transmitter output cascade) and VT5 ( microphone amplifier). To implement amplitude modulation, the possibility of smooth adjustment of the output power of the TX5000 microcircuit is used. A graph of the dependence of the output power from the current through the output 8 of this chip is shown in Fig. 2. If you have a signal from a microphone or microphone amplifier to this output, then you can get amplitude modulation.

In the receiving part, the RX5000 chip (DA2) is used, which is a direct amplification receiver and contains a narrowband filter on surface acoustic waves. It is able to allocate and demodulate AM signals and they have a limit sensitivity of 1 ... 2 μV. To enhance it, an additional UHF is installed at the low-noise transistor VT1.

On the transistors VT2, VT4 is assembled ARU amplifier receiver. With an increase in the input signal at the output of 5 microcircuits increases constant pressure And when it reaches the value of 1.3 ... 1.5 V transistors VT2, VT4 open and the voltage at the output 3 decreases. In this case, the increase in the amplification of the DA2 chip and the AM signal is detected without distortion. The sensitivity of the receiver is about 0.4 μV, and the maximum input signal that it takes without distortion is 20 ... 30 mV.

Nerches assembled on the DA3 chip. Volume adjustment is carried out by a R17 resistor combined with a power switch.

Switch "Reception-Transfer" - SA1. In this case, its contacts SA1.1, which connect the antenna to the output of the transmitter or the input of the receiver, are part of the matching receiver circuits (C1, L1, C2) and the transmitter (C1, L2, C6).

Nourish the device from two galvanic elements Common voltage of 3 V or three batteries. It is operational at a voltage of 2.7 ... 4 V. Current consumed by the transmitter - about 20 mA, a receiver at a low volume - about 12 mA, while the use of 5 ... 6 mA.

To obtain small dimensions of the device, it is used mainly elements for surface editing - permanent resistors P1-12, oxide tantalum capacitors and ceramic K10-17B or similar imported. Strengthened condensers are also for surface mounting, R10 stroke resistor - SP3-19, variable R17 - SP3-3B.

All coils are wrapped with a wire PEV-2 0.3, L1 and L2 on a mandrel with a diameter of 2 mm and contain 3 and 4 turns, respectively, and the coils L3, L4 - on the mandrel with a diameter of 4 mm and contain 4 and 7 turns, respectively. The switch was applied by PD19-2, the microphone is an electret CZ-036 or a similar, dynamic head can be used any small-sized, preferably with a resistance of 50 ohms. Xw1 socket - any high-frequency small-sized, such as SMA. As an antenna, you can use a segment of the cable (without screen) a quarter of the wavelength length.

Most of the parts of the transmitter are placed on a double-sided printed circuit board from a foil fibercker with a thickness of 1 - 1.5 mm, the sketch of which is shown in Fig. 3 (scale 2: 1). The second side is left metallized and connected by contour in several places with a shared wire on the first side. On the board there are high-frequency nest XW1.

For the convenience of mounting the chip to its conclusions, segments of a thin mounting wire are soldered.

The details of the receiver are placed on the printed circuit board, the sketch of which is shown in Fig. 4 (Scale 2: 1), according to the design, it is similar to the transmitter board. Both fees are folded together and peck over the contour, and then set the switch. This is so obtained by a single design, which is placed in the body of a suitable size, the resistor R17 is fixed on its walls, the dynamic head. It is also necessary to make openings for the microphone, dynamic head and high-frequency plug in the housing.

Establishment starts from the transmitter. Its output is connected to the power meter or voltmeter with a consistent load. Changing the inductance of the coil L2 (pushing the coils) and the capacitance of C1, C2 capacitors, achieve maximum output power. The R10 resistor set the highest modulation at a minimum of distortion. Setup must be repeated several times. After that, you can connect the antenna and, if necessary, tune to the maximum field strength.

Then configure the receiver. Changing the inductance of the coil L1 and L4, as well as the capacitance of the C2 capacitor, the maximum sensitivity is achieved. In the author's version, during the configuration, it turned out that the C2 capacitor was set to the minimum capacity position, so it was excluded.

Radio, No. 4, 2006. Igor Nechaev (UA3WIA), Kursk

Micromoger radio station of 430 MHz.

Igor Nechaev ( UA. 3 WIA. ), Kursk

"Magazine" Radio №4; 2006 "

On the use of TC5000 and RX5000 microcircuits to build a system of radio domestic animals, their device and basic parameters, already described in the magazine "Radio" (Nechaev I. "Search for a radio beacon in the range of 433 MHz", 2005, No. 8, p. 44-46 ). The first of them is a transmitter, and the second is the receiver and are intended to construct the radioline exchange of digital data into the VHF range at a frequency of 433.92 MHz.

These chips can be used not only by direct purpose, but also for constructing low-power amateur transceivers with a fixed frequency in the range of 430 MHz. The resulting device will communicate at short distances (hundreds of meters) and come in handy on a walk, rest, etc.

The scheme of the proposed transceiver is shown in Fig. one.

The transmitted part is assembled on the DA1 TX5000 chip, as well as the VT3 transistors (transmitter output cascade) and VT5 (microphone amplifier). To implement the amplitude modulation, the possibility of smooth adjustment of the output power of the TX5000 microcircuit is used. The dependency dependence of the output power from the current through the output 8 of this chip is shown in Fig. 2.

If you have a signal from a microphone or microphone amplifier to this output, then you can get amplitude modulation. In the receiving part, the RX5000 chip (D A2) is used, which is a direct gain receiver and contains a narrowband filter on surface acoustic waves. It is able to allocate idemodology and signal and to them and serve as 1 ... 2 μV. To enhance it at the inlet-to-fulfillment of a low-noise transistor VT1

On the transistors VT2, VT4 is assembled ARU amplifier receiver. With an increase in the input signal at the output 5 of the chip, the constant voltage increases and when it reaches the value of 1.3 ... 1.5 V transistors VT2, VT4 opens and the voltage at the output 3 decreases. This reduces the gain of the DA2 chip and a signal with amalid-creative distortion. Chiselitudes are perceptible to about 0.4 μV; And the maximum input signal that it takes without distortion is 20 ... 30 mV.

A dual da3 microcircuit. Volume adjustment is carried out by a R17 resistor combined with a power switch.

Switch "Reception-Transfer" - SA1. In this case, its contacts SA1.1, which connect the antenna to the output of the transmitter or the input of the receiver, are included in the corresponding receiver circuits (C1L1C2) and the transmitter (C1L2C6).

Feed the device from two galvanic elements with a total voltage of 3 V or three batteries. It is operational at a voltage of 2.7 ... 4 V. Current consumed by the transmitter - about 20 mA, the receiver at a low volume - about 12 mA, while the assembly consumes 5 ... 6 mA

To obtain small dimensions of the device, it is used mainly elements for surface editing - permanent resistors P1-12, oxide tantalum capacitors and ceramic K10-17B or similar imported. Street condensers are also for surface mounting, R10 trimming resistor - SPZ-19, variable R17 - SPZ ZV.

All coils are wrapped with a wire PEV-2 0.3, L1 and L2 on a mandrel with a diameter of 2 mm and contain 3 and 4 turns, respectively, and the coils L3, L4 - on the mandrel with a diameter of 4 mm and contain 4 and 7 turns, respectively. The switch was applied by PD19 2 microphone - an electrometry CZ-036 or a similar, dynamic head can be used any small-sized, preferably with a resistance of 50 ohms. Xw1 socket - any high-frequency small-sized, for example SMA as an antenna, you can use a cable segment (without screen) a quarter of the wavelength length.

Most of the parts of the transmitter are placed on a double-sided printed circuit board from a foil fibercker with a thickness of 1 - 1.5 mm, the sketch of which is shown in Fig. four

(Scale 2: 1). The second side is left metallized and connected by contour in several places with a shared wire on the first side. On the board there are high-frequency nest XW1.

For the convenience of mounting the chip to its conclusions, segments of a thin mounting wire are soldered.

The details of the receiver are placed on the printed circuit board, the sketch of which is shown in Fig. 3 (scale 2: 1),

by design, it is similar to the transmitter board. We fold both fees "together and miss the contour, and then set the switch. This turns out to be a unified construction, which is placed in the case of a suitable size, the R17 resistor is fixed on its walls, the dynamic head. It is also necessary to make openings in the housing for the microwave, dynamic head and high-frequency fork.

Establishment starts from the transmitter. Its output is connected to the power meter or voltmeter with a consistent load. The impendingity of the coil L2 (shutter "of the gay turns) and the capacitance capacity of the condensers1, C2, achieve maximum output power. The R10 resistor set the most speaking modulation at a minimum of distortion. It is necessary to repeat several times. After that, you can connect the antenna and, if necessary, tune to the maximum field strength.

Then configure the receiver. Changing the inductance of the coil L1 and L4, as well as the capacitance of the C2 capacitor, the maximum sensitivity is achieved. In the author's version, during the setup process it turned out that the C2 capacitor was set to the lowest capacity position, so it was excluded.

Another fairly simple and good, but the demanding of the culture of the assembly and geometry of the microwave micro-transceiver on modern elements, the difference of which is the absence of an antenna (frame) and the ability to work up to 4000 MHz.

The prototype of the radio is the scheme of a Czech amateur.

Changed the chains of the LF, the technology and some other nuances of the design are finalized. The principles are very similar to those that I used in the micro-races from the Vox and Pioneer - only a little different microwave heterodyne.

(The option appeared on the photo is apparently (nothing to measure) works at 1560 MHz, determined by the second harmonic of the generator). The scheme perfectly worked on the layout up to 4100 MHz, finishing to the forest from the third floor near the window (about 2.7 km), and through the house 70 ... 150 meters, depends on the walls and windows.

Used triode KT371A in plastics, or similar to it. Bourgeoine SMD can be applied, - by means of a microwave geometry accordingly. However, during the construction of two sectors, problems and excumbers began, especially the UNG transmitter. I had to try 8 (!) Options for the board, and the latter is not apparently not the most optimal, although it works ...

Pay attention to the pictures:

1. The strip resonator (E) is silver and together with the chains is a single transmitter module, separated by the considerations and the screen (on the underside) of everything else.

2. On the reverse side, it can be seen that the screen (b) under the strip is removed (B), for better radiation (the radio operates without any antenna).

3. The photo is connected to a 150 Ohm adjustment earphone (A), but there is a regular speaker (50 ohms) (d). Both options provide a greater volume in the room, with a receiver current about 20 mA.

4. The transmission is turned on by one button.

We bring the variant of the printed circuit and the microwave part of the transmitter. The rest can be syrupted with printing:

Radio module of the circuit and one of the IULC cells (Details of UNUC are visible on the board)

For silvering of a strip resonator, an ear chopper is used to the solution of nitric acid silver. Which in turn is taken from the pubi, into which several milliliters of nitrogen are poured and several pieces of cheap Chinese silver chain are thrown.

In front of silver, the plots are rubbed to the mirror glitter with felt with green paste gay.

The process of polishing and silvering takes up to 10 minutes.

But the results may surprise the adherents of surfactants and quartz stabilization (Narrow strip, high sensitivity, and stability) should be taken into account that since the resonator is not protected by the screen below, it should be placed in the plastic case so that the approach of the hand to it is less than 1 ... 1.5 cm it was impossible.

Walkers with good adjustment provide radius to 1 km and up to 250 m in the city.

With increasing frequency, the distance increases significantly, and work through the wall deteriorates.

I want to warn it: with a very tempting and cool design, good results here are achieved here only thanks to the highest culture of microwave technology, so I ask you to carefully consider every millimeter implementation, including even the installation method and soldering of the microwave blocking containers ...

Note: A variable resistor at 47 to the wires on the wires, which is then replaced by a permanent (receiver mode).

Also, it will also be necessary to obstaciously to suffer with the utmost turn on the transmission mode (selection of the modulator displacement mode, the geometric placement of the microwave blocking capacities at the inlet of the modulator, and D.R.).

In short, the design is promising, good, but I do not recommend "pioneers" and "October".

Micro transceiver with VOX

This miniature transceiver is operational at frequencies from 144 to 960 MHz and provides two-way communication with the inclusion of voice transmission (VOX system) at a distance of 150 meters through the walls and up to 1000 meters in direct visibility.

Constructively completed as the knob on the Crohn battery, does not have a switch, but simply removed from the "crown".

The consumed transmitter current and receiver strongly depends on the components. Also, the range and power depends on the microwave trigger. In the prototype it is CT363B. The remaining triodics are any SMD, for example KT31030A-9

Attention: SMD installation. Top layer - details. Lower layer - solid land.

Round dots, - Jumpers dried to Earth

Attention! There are no two air wires on the seam, from 22 H on the microwave base (modulation) and something in this area .. look according to the scheme for yourself.

Burzhuysky is applied (unknown what) microwave r-n-p triodes. It can be replaced by KT3165A-9 (it seems a little worse than CT 363 b) if not lazy, change the board under the CT-shka.

Antenna wire or spiral efficient 1 \\ 4 or 1 \\ 8 length wave. For 433 MHz, this is about 14 cm.

No special setup required.

If necessary, the superchair mode is selected by the resistor in its base (to land) by pure, loud noise loudly dependent on hand in the antenna.

However, all such devices do not like to paw their antennas and frequency will leave. It is necessary to constructively provide the rigidity of the antenna and its removal from the hand.

Keep the battery package.

In the transmitter, a tricky frequency care compensation mechanism is applied during transmission. If the frequency goes too much during transmission, the connection with the second wagon will be not distant, it is necessary to select resistors in the database and in the upper shift shoulder.

For 433 MHz Communication Coil 1 The coil removed from 3-4 turns of the D-5mm wire F 0.6 mm or the contour coil is simply a semi-leather on the legs of a ceramic trimmer of the frequency adjustment (D-10 mm).

Many similar devices have been collected.

A characteristic trouble is too close or loud sound of the speaker near the microphone - leading to the triggering of the VOX system.

It should be selected the sensitivity of the triggering minimally convenient resistors in the sound detector.

Speaker - any magnetic with a metal membrane R \u003d 25-32 ohms. Microphone - any electret.

For those who have already soldered microwave beetles and receivers, I inform:

In the chains of the LF (VOX detector) and after it, 1 NF capacitors should be replaced with large (watch in meaning) - for example, 22NF. This is a kind of protection against pioneers and schoolchildren.

With the specified rates will work as children's voki-currents. The condenser has a time-sensitive (electrolyte) in the circuit from the output of the logic element to the input, (has a + sign) to replace with 6-10 μF.

Look carefully: if you even beat a little bit at least in UNG, it will immediately become clear to you - where in the diagram logical protection from pioneers, - boldly replace small (1NF) kondics for typical container - in meaning.

Used MS - K561L7 (or its imported analog)

Alexander and Ilya Zohre (Minsk Republic of Belarus)

Last Watching Pionera

The reaction to the article "Micro Transceiver with Vox" and questions, pushed us to publish an even simple and tendentious micro-radio, which I and son I will call: "Last Watching Pioneer"

The network has more than 100 simple pocket racies on ultra-generorators, with a range of up to 1.5 km.

However, all of them both in the element database and on ideology are outdated at least 15 years.

During this time, the understanding of the processes in the ultra-generitor, and the element base has advanced so much that it seems possible and fairly simple, the creation of "bugs" is less than a match box, with parameters are quite serious for a number of applications.

Probable users: Students - two, schoolchildren, athletes, skiers, cyclists and with appropriate design - even motorcyclists.

Modern ultra-generrator is like a New Look On a black hole in astronomy. All swollen it, and ridicule.

However, he surprises us, and is increasingly used for very serious purposes.

For example, spyware (agency) ractions that are inserted directly into the ear, or some super SCHN systems (noise-like broadband carrier) capable of having a sensitivity 100 times lower than noise (0.0001 μV) and not subject to detection - it is among other varieties and hybrids Svehalch with digital Microohu ...

Surely among readers there is a fan that is wondering not only to use, but also to develop scandalous, treacherous ideas that turn our idea of \u200b\u200bthe technique and communication methods!

By publishing this scheme, we hope for the awakening of interest in such a phenomenon as a reception on the threshold of stability, which uses Sverach, and its other unique properties.

(By the way: there are simple spermarts that operate simultaneously in duplex mode (and receiving and transmitting both in the phone) - with the digital (PWM) code and on a very decent distance (up to 2 km) ...

But back to the topic:

This design is called "the last", since actually the further can be taken over the base for all similar homemakes "Voki-Toki", because This is almost the limit of dreams of anyone who does not want to make difficulties.

This scheme is easily placed on the keychain, it can also, together with a 12 volt "alkolin" battery from car alarms, - in the body of broken bluetooth or right in a large earphone. True, it will be only a couple of hours with such a battery ...

The receiver has high sensitivity and stability. This is the squeeze of many such ideas on sakes.

In this embodiment, the sensitivity of the reception on individual copies of KT363 reaches 2-3 μV with a signal ratio \\ noise \u003d 4.

The transmitter power strongly depends on the setting of the communication coil and can reach 60 MW, which is quite enough on this range for communication in the range of 300-1000 meters (as lucky).

Principle of operation and commissioning.

It is all the same superchard on a relatively low-noise microwave triode.

The operating current control system is made on additional transistor and resistors in the emitter of superchair.

With an increase in the operating current, the superization mode is turned off and the response mode is activated.

The UH receiver and the transmitter are made on a logical shutdown trailer (controlled UCH) on the Linear Linear Linear Means.

You can apply any CMOS 4 * 2 and non-case, including K176L67. The sensitivity of the microphone and the volume of the sound depend on the quality of the used CMOS.

When you click the Transmission button, the receiver turns into a transmitter. In this case, the UNG is completely turned off and the microphone amplifier is activated.

Probably, if you do not need to whisper on the exams, the sensitivity of the microphone should be very high, increasing the corresponding resistor (1 K) in the database, because His flair is more applied for "beetle."

The bandwidth is large enough. Please note: not a World Cup namely ACM-modulation - most suitable for such devices. (The system brazenly occupies 7-8 narrow-frequency channels from chinese racies)

The receiver has the properties of the frequency capture according to the Polyakov receivers method, but is not a receiver with the PLG.

The frequency of superimization is quite high (up to 300 kHz) - if desired, it should be reduced to increase the resistor 1 to 5-10 K (in the emitter of superchair). You can also try to increase the capacitor with a parallel resistor.

These manipulations will lead to a significant narrowing of the strip, narrowing the capture strip, increasing sensitivity, reduce the resistance to the channel disorder, reduce the resistance to a drop in supply, increasing the volume at the outlet and other effects ...

Some La7 CMOP series work poorly in linear mode. Therefore, with a hoarse voice in a microphone or on the phone, or the absence of a signal of the signal, check the mode and select the resistors (1000 K). The correct mode is when the feeder voltage is exactly 1 \\ 2 at the output of the element.

If the scheme is beeps, - try adding 1-2 NF to the inputs or outputs (to Earth) amplifiers, or what is especially characteristic: you have a Chinese low-voltage battery "Crown" (and especially 12 V - for alarm). Put the electrolyte large (20-50 Igf) parallel to the battery, and \\ or 10 nf.

In general, the correctly collected radio is launched without problems.

It is easily able to determine the work easily according to the characteristic skewer noise, it must be without whistles and wheezes.

The noise is broken when touched by a screwdriver or tweezers to the superchalter collector.

Determine the range and configure it, easily by keying the car alarm by clicking the keychain button at a distance of 2-300 meters. The distance will tell about the sensitivity of the receiver.

Determine the operation of the transmitter easily by simple arrow (or other) microwave probe, or in extreme cases, the short-lived multimeter (voltmeter) of the microwave or shatter-diode and bringing the transmitter antenna close to Schu ...

After setting up the receiver to the signal, the transmitter will automatically be configured to close the frequency, which, taking into account the capture), will be quite close to the second similar correctly configured radio.

To completely eliminate the frequency of the transmitter (increasing range), you can improve the scheme, so - as I show the next time.

This scheme was repeated repeatedly.

In conclusion, we note that this scheme It will also work on 3-5 thick watch batteries from laser pointer, but the range will fall to 80-200 meters - respectively.

Mount on a double-sided sheet, the bottom side is solid and connected to the mass (- power). The connection points of the circuit with the mass must be short (1-3 mm), are made drilling and subfit to the bottom layer.

In the microwave, there should be no connecting tracks in the microwave - all connections directly to the parts themselves or not longer than 1-4 mm.

One option (visible blue button, contacts for "laser" batteries and antenna tail. Also visible print coil (snake and communication coil - rubbing around it)

This spring, something wrong was going on with our driveway intercom and while in the state of "premonition of his repair" I remembered my long desire to put the camera in it. And in this regard, I had a question - how to transfer an image to an apartment? Pull wires - I don't really want. You can of course buy a wireless Chinese camera for 1.2 or 2.4 GHz, but then the signal will be able to watch only me and those people who buy receivers, and they are quite expensive and separately from cameras. You can of course buy one receiver, and for the rest of the "subscribers" to make an image of a cable, but in this version there are problems ...

And then I came to mind the idea of \u200b\u200bcreating a low-power video speaker, moreover, I already had the experience of creating such devices. Inspired by this idea, I began to study this topic on the Internet. Hoping to find a scheme of something simple and universal until I stumbled upon the site www.vrtp.ru and specifically the topic of the forum dedicated to the transmitter for 430 MHz (59 channel). The author under the nickname "Cylllka" developed a small transmitter on the surfactant resonator. The HF part of this scheme I took the basis, because in the forum enough people repeated it with positive results. Cylllka and the rest of the guys (especially "Mikhalych2" 🙂 have done a lot of work on debugging the shown scheme. For what they have a huge respect!

Video transmitter scheme

The only thing I decided to change in this scheme is a modulator amplifier. Since I know by experience that such amplifiers-modulators are very "capricious", sensitive to the input resistance and the level of input signal, as well as the gain of transistors. And therefore I used the scheme of an amplitude modulator published in the collection "Encyclopedia electronic circuits» Count and Shield, which has already collected and had the experience of its setting. That's what I did:

Scheme of experimental video student 430 MHz.

A small theoretical retreat ...

What details and tools are needed

The video identifier I decided to assemble on the SMD components, as I like to work with them and they are ideal for HF devices. They can be bought in the store or fall from old boards. Good source of parts are boards from old automotive phones different standards (NMT-450, GSM) Motorolla, Bosch, Siemens and them like. This is a valuable source of high-quality inductors, HF transistors, quartz and other small things. So, for assembling the device you will need:

Soldering iron with a thin stale and adjustable temperature, neutral flux, solder 0.25 mm thick, soft, thin chain for applying flux;
Fungalized fiberglass with a thickness of 1 mm (0.8 mm, 0.5 mm), chlorine iron for etching;
Scalpel, tweezers, nippers;
Magnaya (as needed);
Handbook on the marking of SMD components;
HF transistors: BFR93A, 2SC3357 (56), BFG135 or close to parameters analogues;
NF transistors: BC847. (BCW60., other similar), BC327. or similar PNP, BCP56.;
SMD resistors (1206);
SMD capacitors (0805);
Pav resonator 420-450 MHz (0604 or in any other case);
Enameled wire diameter 0.3-0.35 mm.;
Strip Resistors 1 Kom, small;
Stabilized power source 6V;
Tester;
RF receiver, radio station;
Oscilloscope, frequency meter - I did not use;
Beer, coffee and sandwiches - depending on the time spent!

Production of printed circuit board

Printing - the basis of any electronic device. I make laser-ironing technology fees (LUT). The description of this technology is on the Internet. It can be said that this technology has changed the world of radio debt. Now in one evening it became possible to manufacture enough complex printed circuit boards at home. Briefly talk about the main points of this technology. We develop a printed circuit board anywhere - with special programs or vector editors. For example, I use the Visio program (drawing of the Visio format). The resulting image of the conductors on the printed circuit board is exposed mirror display And printed on laser printer On glossy (cooled) paper (magazines).

We prepare the foil fiberglass - we clean the shallow sandpaper and degrease the alcohol or acetone. On the prepared textolit, we put the printed image of the printed circuit board - toner to the copper foil and the entire "sandwich" cover with several sheets (the old newspaper 5-7 layers). I use the old book for this process in a soft cover - just putting a fee with stencil inside. Heat the iron at the maximum and stroke our "sandwich" by pressing strong enough! I make 2-3 approaches for 15-20 seconds. After the first approach, it is necessary to check the position of the stencil on the foil - it should not slip ... In the course of this procedure, the toner is melted and is transferred from the surface of the paper on the copper foil. And due to the fact that the toner does not dissolve in water - we can use this process for the manufacture of boards.

After the board has cooled placing it in a container with warm water for 15 minutes. As a result of this action, paper turns, and we can gently roll it with your fingers. On the board only translated tracks. The board is ready for etching. Polevim in a hot saturated chlorine iron solution to minimally reduce the etching time. We wash the fee in running water and erase toner acetone - the board is ready for a tinning.

In principle, the high-quality logging of printed circuit boards for high-frequency circuit equipment is possible only by chemical methods or immersion in the melt, followed by a "blowing" of solder residues. But, if you do it carefully and do not rush, then at home you can do it high quality. You will need a soldering iron, a good flux (neutral) and a solder with a diameter of 0.25 mm. Cover the flow fee and warming up the soldering iron footpath. We start their logging using. minimum number of solder. "Fat" solder for such small boards - not very suitable. Quickly appear surplus solder on the board. And attempts to remove them usually lead to overheating and peeling the tracks.

I usually immediately I make 2-3 fees, especially if they are small and you strongly recommend that. Even if one fee is damaged when etching or tinned (this sometimes happens), there will always be a "strategic" reserve.

Installation of the device

In the installation of SMD elements there is nothing complicated. There are several ways to solder them. I usually use the following: I put an element on a printed circuit board, holding the element of the tweezers, nano on its contacts with a thin, soft brush flux. After that he warming up one end, and it rolls to the board at the expense of the sickness of the mezzani. After that, if necessary, hang an element and then it is already soldered using fine solder.

The fee was developed under multi-turn variables of Murat resistors (blue), but during the installation process found a couple of smaller "tricks". I had to make a jumper and cut a fee.

After the installation is completed, the board is washed with a soft brush in warm water with Fairy or something like that. As a result, a device should be turned out as in the photo below or something similar.

Setting the transmitter

The device setting consists of two stages. At the first stage, it is necessary to make sure that the RF generator earned and the device has a "good" carrier frequency at the output. To do this, feed meals on the emitter of the transistor BCP56. and try to take the carrier frequency (I have it 433,440 MHz) on receiver or TV in channel search mode. Usually, the unmodulated carrier frequency "is displayed" on the TV is a black screen (not ripples). I used to configure portable radio station Yaesu VX-6 - To control the carrier frequency in AM mode and in parallel with this, received an ICOM IC-R3 signal in NTSC mode.

After I earned the RF part of the device, I began debugging the modulator and filed a signal from the DVD player. Matvey watched cartoons and I took advantage of a Luntik for debugging the device. To select the operating point of the transistor BC327 I had to put a variable resistor to 1 to its base chain and to hide it with a capacitor. After that, the modulator earned and the frequency modulated amplitude appeared at the device output.

Current consumed by the device - 160-180m. Video quality - as wire. Variable resistors in the video can allow you to configure it almost in all parameters (level, linearity and depth of modulation). Signal power (approximated by the carrier, approximately 100-150 MW). On the IC-R3, the signal is accepted in the yard, with the length of the transmitter antenna - 10 cm.

Heniv Vasily.

March, 2009.