UKH-FM Radio

Currently, there are many Chinese-made radio receivers, which, due to low sensitivity, do not work equally well everywhere. However, it is not at all difficult to make a radio receiver using ready-made blocks from old TVs. As practice shows, such receivers have quite greater sensitivity, which is important for lovers living far from the location of the antennas of transmitting stations, especially in the mountainous terrain. Similar "Darm" stationary receivers are conveniently used in garages, workshops, boat stations, etc.

In the TVs released in the CIS, the principle of obtaining an intermediate frequency of sound accompaniment as a difference in the frequency frequencies of the image and bearing sound support is used; which is 6.5 MHz. When receiving television signal At the output of the channel selector, after the conversion there are signals of the intermediate frequencies of the image of the FPCH \u003d 38 MHz and the sound of the F / | | \u003d 31.5 MHz, of which the second intermediate sound signal is formed (difference frequency) of the F / || \u003d 6.5 MHz. It is clear that to receive broadcasting signals from the air, having only one bearing frequency of sound without a second signal, it is impossible to the television receiver, as it is a super-enerodine with a double frequency conversion. If instead of the FPCI, it is possible to receive an option to receive a broadcasting stations with frequency modulation (CHM-FM) instead of the FPCI.

In other words, to solve this problem, it is necessary to make an external heterodyne (a 38 MHz sinusoidal generator with high frequency stability) and submit a signal from it to the upch input. The setting to the station is performed using a potentituetr of the voltage change in the Varicaps of SC-M-24-2C.

It should be noted that when the supply voltage is disconnected by the additional generator, the broadcasting station will not listen to.

Principal electrical circuit additional generator is shown on fig.1. This is a classic capacitive three-way with a quartz resonator QZ1 by 38 MHz. The outline in the VT1 transistor collector circuit is configured strictly on the first harmonic of the frequency of this resonator using the SZ trimmed condenser.

Constructive data of coils of the generator circuit:
Frame from television receivers of the CNT-47- III with a diameter of 8 mm (cylindrical screen);
L1 - The contour coil contains 10 turns of the wire PEV-1 with a diameter of 0.5 mm with a tap from the 3rd turn (an account from the top end of the coil).
L2 - the communication coil contains 2 turns of the wire PEV-1 with a diameter of 0.5 mm.

In the manufacture of the contour, L2 is at the bottom of the frame at the bottom of the frame, and then L1. Core from carbonyl iron type SCR-1 is introduced into the end of the coil L1, which allows, if necessary, to change the inductance of the L1 coil.

The drawing of the printed circuit board of the generator 38 MHz is shown in Fig. 2, and the location of the parts is in Fig.Z. PC sizes 67x43 mm.
The author made several stationary receivers from ZUSTST TVs, usually faulty. If there is a place, for example, in the garage, then all the necessary alterations can be produced, without disassembled the TV completely, right in its case.

Since the TV receiver is used by the author only to listen to the sound support of telecast and radio broadcasting, then the TV is removed from the kinescope, deflecting the system, TVs with a multiplier and the transistor of the lowercase sweep (CT838).

Meter Range channel selector (SK-M-24-2C) has a control socket "Out. The PC ", to which, through a capacitor with a capacity of 1.5 PF, a predetermined 38 MHz signal generator is connected. Thus, the frequency from the additional generator will go on the submodule of the Radio channel of the CMRK-2, where it will be used to obtain a difference frequency of 6.5 MHz. When receiving sound television canals The external generator is powered by an additional switch installed.

Receiving broadcasting stations is made in the TV range | - || (television channels 1-5), which corresponds to a frequency overlap 49.75 .. .99.75 MHz, but in practice SK-M-24-2C takes signals with a carrier frequency to 107 MHz.

Despite the fact that in broadcasting, as a rule, vertical polarization of the wave is used, the usual television antenna of the meter range, as a rule, provides a normal reception. Nevertheless, for better reception of distant radio stations, it is better to use an antenna with vertical polarization or ordinary television antennaBy turning it at 90 °.

It should be noted that the sensitivity of such a receiver is quite high, and many broadcasting stations are taken on a telescopic antenna under favorable conditions.

If desired, the receiver can also be collected in the housing of significantly smaller sizes than the TV case. In this case, only one module is sufficiently removed from the TV to use the entire module - the radio channel module, for example, A1 MRK-2. The board of this module is installed and interconnected by the SK-D-D-24C channel channel selector, MV channel selector Type SK-M-24-2C, submodule Radio channel of CMRK-2, as well as sub-module SHROP synchronization. When receiving broadcasting and sounding television programs, the board A1.4 (USR) is not used, and it can be removed.

In order to simplify the receiver scheme, the restructuring by frequency is carried out using a potentiometer connected to the rectifier with a voltage 32 V. The potentiometer should have a linear characteristic of the dependence of the resistance from the angle of rotation of the movable contact (group A).

An additional signal generator for 38 MHz is the same as described above. It connects to the SC-M-24-2C to the socket "Out. PC "through a condenser with a capacity of 1.5 PF. From the CMRK output, the beep enters the sound frequency power amplifier (UMP). Umzch can be applied any sensitivity of about 70 mV. You can also use the UMP on the K174UN7 chip from the same TV, which is on the A9 board (BU-2-2 control unit). The power supply voltage is supplied + 12 V. The numbers of the contacts of the connectors A1 connectors to connect the power, turning on the ranges, feeding the setting voltage and the output of the low-frequency signal is shown on the Fig. 4 block diagram.

Using the SA1 switch, select the desired range, and when receiving a broadcasting stations, you must enable the SA2 switch ("RV") and apply the power to the generator 38 MHz, and when receiving the TV shows, the SA2 switch must be turned off (TV "),

The receiver assembled from the blocks from the TV and two additional circuits is powered by a stable voltage of +12 V and +32 V (to change the capacity of varicaps) from the power supply, the diagram of which is shown in Fig. 5.

In this power supply, the TC40-2 type power transformer is used, the semoisemind of secondary windings T1 must be included according to the Fig. 5 scheme.

In principle, in this BP, you can use any power transformer power 20 ... 30 W with suitable stresses on the secondary windings 12.5 ... 14 V and 18 ... 20 V.

The power circuit of the power supply has no features. For the power of the UMP and the radio channel, a bridge rectifier was applied on VD3-VD6 diodes, and for the control of varicaps, a voltage doubling circuit on VD1 diodes, VD2. Power supply stabilized by the simplest stabilizers. To compensate for the voltage drop on the VT2 transistor, the VD11 diode was introduced into the scheme.

Literature
1. Kuzinets L.M., Sokolov V.S. Nodes of television receivers. Directory. - M.: Radio and Communication, 1987.
2. The conceptual electrical circuit of the TV photon 381d.

S. Baisn. PGT. Kellamenti, Chernihiv region.

A source:
Download: Stationary VHF FM Radio from modules from old TVs
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Broadcasting B. ranges of VHF allows you to provide radio listeners more high quality Audio signal in comparison with broadcasting in the ranges of long, medium and short waves. Moreover, the struggle for the quality of the reception led to the emergence of industrial and radio amateur receivers exclusively for receiving in VHF bands.

To the attention of readers is offered one of these amateur developments. And although the author calls his design difficult, we are not inclined to dramatize the assessment. Just say that improving the quality of work (good stereo in two standard formats) requires certain costs.

The described design design is intended for listening to broadcasting stereo and monophonic violations of radio stations in the range of 65.8 ... 74 MHz and 88 ... 108 MHz, as well as sound support of television gear on all MB channels and DMV.

The possibility of receiving stereo programs both with polar modulation and a pilot-tone is provided. In the memory of the receiver, you can pre-program the setting of 55 radio stations and, if necessary, quickly select any of them using the remote control remote control or directly with buttons on the front receiver panel. Volume and stereo balance are also adjustable both remotely and from the control panel. The number of the received channel and all the necessary information During the setting is displayed on a two-bit seven indicator.

The proposed design is an attempt to create a convenient device suitable for high-quality stereo reception in locality with large quantity television and violas of radio stations. Despite comparatively complicated schemeThe receiver is easy to establish and operate. It is assembled from the available details and consists of several functionally completed blocks collected on individual boards. This allows you to easily make any changes and additions to it.

The receiver is made according to a diagram with a double frequency conversion. The signal adopted by the antenna is converted to the first PF of the standard television selector of the SK-B-418-8 channels. SK-B-41 can be used or any imported, designed to work in MB bands, DMV and KATA ( cable TV) 110, .. 174 MHz. Apply Outdated SCM-24 selectors is not recommended, as they do not overlap the range of 100 ... 108 MHz and have less amplification.

As is known, any super-energous receiver, in addition to the main channel, has both unspossed channels of reception on the mirror and intermediate frequencies, as well as due to the transformation on the harmonics and subharmonic frequency of the oscillations of the heteroodine, i.e. Reception at frequencies

fNP \u003d MFG ± NFC,

where m, n \u003d 1, 2, 3 ...; FNP - intermediate frequency; FG - the frequency of the heteroodine; FC - signal frequency.

The receiver has two heterodyne, so extruded channels in it even greater, since heterodyne signals can interact among themselves on nonlinear device elements. Of course, the overwhelming majority of these side channels is filtered off by the inlet contours of the channel selector and strip filters of the first and second IF.

However, the frequency of the heterodyne and the PC is still recommended to choose so that the combination frequencies are not in the field of frequency of the useful signal. In other words, near the radio stations taken in this area there were no affected points. This selection is achieved by the first IF value, which must lie within the frequency of 32.5 ... 38 MHz. In the copyright, the first PC is 32.8 MHz (PC1).

From the output of the channel selector, the PC1 signal is fed to the input of the BC-FM unit (A2). Its scheme is shown in Fig.1. After enhancing the cascade on the VT1 and the two-integral band filter L1 - L3, C4 - C8, the signal is fed to the second frequency converter, made on the DA1 chip. Gometerodine with an oscillatory circuit on L4, C10 - C 13 operates at 22.1 MHz. The second PC standard is 10.7 MHz (PC2). It stands out on the L5C15 circuit, passes through the ZQ1 main selection filter and enters the Multifunctional DA2 chip. The filter must have a bandwidth of 250 ... 300 kHz. You can use a focal selection filter type FP1P-0496 or any imported.

Fig.1 (Click to enlarge)

The OD2 microcircuit is enabled according to the typical scheme and maintains the main strengthening, restriction and demodulation. In addition, it produces an APCH voltage and a setting signal ("Setup") submitted to the control unit. Upon receipt of this signal, the control unit reduces the speed of rebuilding the receiver to facilitate the exact pre-tuning to the station. From the control unit on the output 2, the DA2 microcircuits arrives the "Block. APCH" signal, turning off APCH for the time of rebuilding the receiver.

The demodulated LB signal from the output 7 of the DA2 chip through the R22 resistor enters the input of the stereo-componer block (A3). The diagram of this block is shown in Fig. 2. On the transistors VT1, VT2 a pre-amplifier is assembled. Mounted R5 and R6 resistors are designed to select optimal level Input signal for chickens of stereo-componers DA2 and DA1, respectively.

Fig. 2 (click to enlarge)

The stereoder for the signal with the polar modulation according to system 01 RT (the frequency range of 65.8 ... 74 MHz) is made on the K174HA14 type DA1 microcircuit. Apply more modern development K174H35 is not recommended, since in conditions of real signals, it works very unstable, with a very noticeable clocks and constantly switches from the "Stereo" mode to "Mono" mode. The stereoder on the K174HA14 chip works much more stable. It is assembled according to the scheme described in detail.

The stereoder for a signal with a pilot on the CCIR system (frequency range 88 ... 108 MHz) is assembled on the TA7342R type DA2 chip also according to a typical scheme. Switching stereoders is carried out by the "PM / Pilot" signal supplied from the control unit. For high level This signal transistor VT3 is open, and the VT4 transistor is closed and the supply voltage is supplied to the DA1 chip. With a low signal level, the power is supplied to the DA2 chip and turns off from the DA1 chip.

Both microcircuables used have an automatic integrated "mono-stereo" switch, so the forced switching on the MONO mode is not provided. To go to this mode, it is enough to simply turn on the "non-one" stereoder. For example, for receiving in monophonic mode of a station operating on a system with polar modulation, you need to turn on the stereo-speaker for the system with a pilot. Of course, a slightly complicating scheme of the A3 block, you can implement the forced inclusion of "mono". However, as the practice has shown, there is no need for this. The output signals of stereoders are fed to the input of the filter block and the electronic volume controller A4. Its scheme is shown in Fig. 3.

Fig. 3 (click to enlarge)

A pre-amplifier is assembled on the DA1 C548Un1 chip. Its purpose is to normalize the levels of signals from the outputs of stereoders. As a DA1, it is permissible to use any low-noise OE in standard inclusion. On the DA2 microcircuit assembled active filter Suppressing the residues of the subcarrier frequencies of the complex stereo signal. In the absence of a microcircuit, the K174UN10 filter can be collected according to any other scheme, for example, as recommended in.

The electronic volume control and sterea balance is assembled on the DA3 of the A4 block by a typical scheme. Adjusting voltage is fed to the conclusions 13 and 12 of this chip from the control unit. The signal from the outputs "Out. 1a" and "1B" is fed to an external connector for recording to a tape recorder. Its level does not depend on the volume adjustment. From the outputs of "Out. 2a" and "2B", the signal is fed to the power amplifier and on the connector designed to connect an external high-quality terminal UH.

Receiver power amplifier (A5) is made on the K174UN14 microcircuit. It does not have any features. The diagram of one amplifier channel is shown in Fig. four.

Fig. four

The power supply (A6) is collected according to the transformer scheme, its scheme is shown in Fig. five.

Fig. five

The receiver control unit (A7) is made on the basis of the "television" controller KR1853VG1-03. Its scheme is shown in Fig. 6. Basically, it repeats the CH-44 setup system scheme for domestic 4-generation TVs. Differences are to exclude the duty regime and in the diagram of the range decoder.

Fig. 6 (click to enlarge)

The decoder is made on the DD3 chip and VT7 transistors - VT9. The need for such a complication of the scheme is explained by the fact that in the controller, the speed change speed is different in different bands. The radio signal occupies a significantly less frequency band than television, therefore, the speed of restructuring in the range should be less. In the proposed diagram, the 1-2 controller range is not used, the range 3 corresponds to the frequency band 50 ... 100 MHz, the range of 4-5 - 100 ... 230 MHz, and the R - DMV range.

On the indicator, the ranges are displayed as shown in Fig. 7: a) - voltage in the lower end of the range of 50 ... 100 MHz; b) - in the center of the range of 100 ... 230 MHz; c) - in the upper end of the DMV range. The top pair of the indicator is used in mode for three-level setting voltage settings. The HL1 indicators block has a circuit with a connection of elements with a common anode, the type of indicator of any, for example, Kipps09I-2 / 7K.

Fig. 7.

For remote control, the standard remote control of the PD-44 (RC-401) is used from the 4th generation TVs. This console is made on the basis of ITT IRT1260 chip, which has a domestic analog of KR1056Hl1. Purpose of the local keyboard buttons is given in the table. The corresponding PD buttons perform a similar function.

The temperature coefficient of stabilitons VD6 and VD7 (see Fig. 6) determines the stability of the receiver setting. In the author's version, the best thermocomptionation of the frequency of the heterodyne turned out to be used by four consecutive stabilion included - two D814B and two KS191F. CHR1853VG1-03 microcircuit is an analogue of SAA1293A-03 of ITT, KR1628RR2 - MDA2062, the input amplifier IR DB TV2800 has domestic analogs of KR1054UI1, kr1054Hase, kr1056UP1, kr1084ui1. Find numbers in fig. 6 are shown for CR1628Р2 and TV2800 microcircuits in the case with 14 conclusions. For the 16-pin case number of the conclusions from the 8th to the 14th, it should be increased by 2. The SB1 - SB12 buttons - on the closure without fixing.

The circuit of the receiver inter-block connections is shown in Fig. eight.

Fig. 8 (Click to enlarge)

Chokes L1 - L7 are ferrite tubular magnetic pipelines, suitable on the appropriate conductors. You can use magnetic pipelines from ferrite F600 from chokes DM-0.1. The L8 and L9 chokes used DM-0.1 with an inductance of 500 μH. HL1 - HL3 LEDs are placed on the front panel of the receiver, HL1 indicates the setting to the station, A HL2 and HL3 - the presence of a stereo signal over the system with polar modulation and the pilot-tone, respectively. The elements C1 - C4, R1 - R4, L1 - L9 are located on the conclusions of the Blocks A1, A5 and A7. The connectors x2 and x3 of the OTC-KG-4-5 / 16-P unit are designed to connect the inputs of the tape recorder and external umzch, respectively. They are located on the rear wall of the receiver. They also place them1 to connect power 220 V and x4, x5 to connect acoustic systems Channels A and V.

This design is designed to repeat fairly qualified radio amateurs, so the drawings of printed circuit boards are not given. When placing parts on the fees, it is necessary to adhere to the general rules for the installation of high-frequency structures. Inside the board housing, it is necessary to be placed in such a way that the channel selector and the PC-FM unit are at maximum distance from the control unit. Adjustable transistors and microcircuits of stabilizers and power amplifiers need to be fixed on the radiator as far as possible from high-frequency blocks and stereoder blocks.

All contour coils in the PC-FM block are wound with a PEV wire of 0.28 mm on frames with a diameter of 7 mm with trimming of ferrite F100. Such frames were used in KB circuits of the Ocean receiver ranges. Communication coils are wound with a wire of a 0.1 mm PEV over the corresponding contour coils. All oscillatory outlines are enclosed in brass or aluminum screens.

The number of turns of coils: L1 - 3 + 3, L2 - 6, L3 - 3, L4 - 10, L5 - 6 + 6, L6 - 5, L7 - 6.

Elements of the C6, R7, R8 stereo components block according to the reference data on the K174H14 chip14 should be selected with an accuracy of ± 1%, but without much damage to quality it is quite possible to use the nearest standard nominal value. Capacitor C12 - non-polar. If there is no condenser of the desired tank, it can be made up of three K10-47 (option A).

No button number A7 (Fig. 6)	Standard	Name in the receiver	Function performed
		Setting +.	Increasing the voltage setting
			Forced inclusion of "Mono" mode (not used)
		RANGE	Selection of range
		Setting	Reducing the tune setting
			Street balance right-left
			StereoBean left-right
			Switching systems Polar modulation / pilot-tone
		VOLUME-	Reducing volume
		Volume +.	Volume increasing
		PROGRAMS-	Bruep the channels in the direction of reduction
		Programs +.	Switching channels up to zoom

CONDENSERS C9 and C30 determine the frequency of the hum of chip, so they should be with a smaller TKE. From old types you can recommend CSR-g. The remaining elements of the block of special requirements is not presented.

Establishing a block A2 effects of the features does not have and executed according to the standard method. The C9 condenser must be soldered directly to the conclusions 12 and 1 of the K174X6 chip from the printed conductors.

Establishing a block of stereo-componers A3 consists in adjusting the frequency of the hum of resistors R9 and R29 to a reliable frequency capture by the subcarrier System of the FAPC chip. This moment is determined by the ignition of the HL2 or HL3 LED. Resistors R5 and R6 achieve the same level of signals at the output of stereodetrov.

In the control unit, you must set the options in the non-volatile DD2 memory. This is done in service mode Only with the remote control. To enter this mode, you must press and for 0.5 with hold the "Service" button. After the symbol appears on the symbol indicator, "CH ° should be released and re-press this button. After the" OR "symbols appear, you need to select the option number on the left indicator with the" Volume + "or" volume "key, and then install or reset the corresponding options on the right Indicator using the PD number keys. All necessary installations are shown in Fig. 9.

Fig. nine

After programming each byte of options, you should press the "Memory" key PO to record information into non-volatile memory.

Pre-configuration on the radio station is carried out similarly to setting up the 4th generation TV with the CH-44 setup system. First, you need to select the range with the "Range" button, then the "Setting +" or "Setting" remote control or local panel to tune in to the desired station, and select the appropriate system with the "PM / Pilot" button. In this case, the indicator begins to flash. Turning on the stereoder for a system with polar modulation is indicated by a glowing point on the right acquaintance of the indicator. Then the "Program" or "Program +" program "select the channel number for the station in the range from 1 to 55. You can use the Digital Pow keys. To memorize information, you must press the "Memory" key, while the indicator stops flashing. In the future, the configuration of the programmed stations is carried out by overwhelming the channels to zoom in or decrease by the "Program +" or "program" by the "Program" or "program" by the "Program" or "program" by the "Program" button. With remote control, direct input of the channel number is possible by digital buttons. The position of the volume and sterea balance regulators is also entered into non-volatile memory when the "Memory" button is pressed.

In more detail the operation of the KR1853VG1-03 controller and the setup procedure is described in and.

Total consumption from sources +5 V, +12 V, +14 in no more than 0.6 A, and from the source +45 V - 0.05 A.

Literature

1. S. Chepulsky. Stereoder in the radio "Ishim-003-1". - Odiguer, 1994, No. 12, p.15-18.
2. P. Belyatsky. Stereo decoder. - Radio, 1996, № 3, p.26.27
3. Integral microcircuits. Chips for television and video equipment, vol. 2 - M.: Dodek, 1995.
4. Yeljashkevich S.A., Peskin A.E. TVs of the fifth generation. Directory. - M.: KUK-A, Symbol-R, 1996.

See other articles section.

Read and write Useful

Ahh FNH L1-C14-C15 can be viewed in advance using the 3h and oscilloscope generator. The mixer is balanced using R13 at the maximum amplitude of tags. The average frequency label generator should be configured separately and in advance to measure its frequency.

The described label unit is connected to Pi with an input frequency of 45 MHz according to the scheme shown in. The supply voltage + 12V (+10 B for DD4) comes from the PI power supply.

Y. Dailides (EW2AAA)

Literature:

1. Y. Daildes. Panoramic indicator. - Radiomir. Kb and VHF, 2002, NN4 ... 6.

2. V. Hypnik. Device for monitoring and establishing radio amateur equipment. - M.: Patriot, 1990

GKC from SCM-24-2 Radio №12 1999

Magazine "Radio", number 12, 1999.

Currently, many replace third-generation televisions more modern. Throw old and faulty on the landfill is sorry. Meanwhile, uncomplicated devices can be collected from individual blocks and nodes of these devices. About one example of unexpected use of selector television channels and told in this article.

From the selector of television channels SK-M-24-2, you can assemble the prefix to the oscilloscope - the swinging frequency generator for viewing the ACH radio and television devices in a wide frequency range - 0.5 ... 100 MHz. At the same time, the manufacture of the device is mainly in harvesting from the selector of the channels of those unnecessary for this device parts and the addition of a small number of new ones.

This GCC has a classic structural diagram of instruments of this group (Fig. 1). It has two G1 and G2 generators that are tunable in frequency by changing the voltage. The limits of the rearrangement of the first GCC generator - 150 ... 250 MHz, and the second - 150 ... 160 MHz. The deviation of the frequency of the G2 generator is achieved by changing the capacity of the varicap in the oscillatory circuit with a sawdust voltage from the oscilloscope sweep unit. The high frequency voltage from these generators is fed to the mixer U1, at the output of which the vibrations of the difference frequency of 0.5 ... 100 MHz are formed, with the deviation of the selected center frequency to ± 5 MHz. This voltage via the emitter repeater A1 and the lower frequency filter Z1 is fed to the A2 amplifier, and from it through the coercive Cascade A3 to the output of the device. The gain A2 and, accordingly, the voltage at the output of the GCC is regulated by electronic method.

The scheme of the GCC is shown in Fig. 2. G1 and G2 generators are assembled accordingly on the transistors VT1 and VT3 according to a circuit with capacitive feedback, which is carried out through C7 and C8 capacitors. High-frequency oscillations with generators through C1, C2 capacitors, and VD1 diodes, VD2 are enrolled on the Emitter of the VT2 transistor that performs the role of the mixer. After the emitter repeater on VT4 vibrations of the difference frequency, the highlighted FGH (L3-L5, C15-C18, C21) is entered on the VT5 transistor to gain. The emitter repeater on VT6 serves to optimally match the amplifier with a load.

The management of the central frequency of GCC is produced by a variable resistor R26, and the adjustment of the frequency band under study is R28. The deviation of the generator frequency is regulated by a variable resistor R29. The output voltage of the GCC is changed by the R25 regulator. It should be borne in mind that the maximum depth of deviation essentially depends on the amplitude of the sawtooth voltage supplied from the oscilloscope.

Additional details, in addition to the channels in the selector, are shown in the diagram of thicker lines.

The device described allows you to restructure in wide range Frequencies without using the range of ranges. The working range of GCC frequency range is limited in the range of 0.5 ... 100 MHz properties of the applied by the FNH and the necessary separation between the generator frequency and the maximum difference frequency.

In the manufacture of the device, it is necessary to compare its principal scheme with the SCM-M-24-2 scheme and draw extra details from the block. Naturally, the appointment of the conclusions of the board connector is somewhat changed relative to the source. In addition to the remaining parts on the board, the transistors VT4, VT6, resistors R14, R16, R21-R24, C15-C18 capacitors, C23-C26 condensers, L3-L5 coils are installed. In this case, all the newly installed coils and capacitors are taken from the number dropped from the board; For example, L3- L5 is the "single" coils from the selector input filter.

The location of the coils L1 and L2 directly on the block circuit board in the immediate vicinity of other parts impairs their goodness and, therefore, reduces the stability of the output frequency of the GCC. Therefore, the coils L1 and L2 are dropped from the board, and in the resulting holes, the segments of the tinned wire 1 cm long and the coils are already soldered again, placing them between the board with the parts and the top cover. The described location of the coils L1 and L2 is convenient and when the instrument is established. They can be repeatedly soldered and drawing out, without violating the integrity of printed conductors.

Variable resistors - any small. XS2 and XS3 connectors, which uses small-sized jacks for connecting stereo telephones with a plug of 3.5 mm, installed on the walls of a tin box attached from the outside to the device from the XS1 connector side. Capacitors C27, C28 (K50-12) and resistor R27 (MLT) are mounted by attachment on the contacts of variables of resistors and connectors.

The main G1 generator is adjusted by the selection of the inductance of the coil L1 by stretching or compressing its turns, and the frequency meter check the generator overlapping range on the VT1 transistor. In this case, the XS1 connector turns off the power of the G2 generator on the VT3 transistor.

Similarly, adjust the G2 generator in the specified frequency band, turning off the power of the other. This setting is made at maximum voltage on VD4 varicap.

The lower frequency filter L3-L5, C15-C18 is adjusted to transmitting the signal in the frequency band to 110 MHz. After adjusting the filter, the L3 and L5 coils have 11 turns with an inner diameter of 3 mm, L4 - five turns with a diameter of 4 mm.

The schematic diagram of the detector head is shown in Fig. 3, and the diagram of connecting devices during measurements - in Fig. 4. It should be borne in mind that the oscilloscope used in conjunction with the GCC should provide a "decaying" sawtooth voltage (for example, a widespread oscilloscope C1-94). If there is only an incremental oscilloscope with an increasing "saw", then the deviation of the GCC frequency must be produced by the G1 generator.

The magnitude of the output voltage of the GCC can be judged by the following measurements. Constant pressure At the output of the detector head connected to the GCC output, in the middle part of the range of 0.9 V, and at the edges of the range - 0.3 and 1.9 V. Considering that the detector head is made according to the voltage doubling scheme, the variable voltage at the GCC output scheme accordingly twice below.

The appearance of the console is shown in Fig. 5 (control knobs from the axes of resistors are temporarily removed).

Literature

1. , TVs 3UST, 4UST, 5UST. Device, adjustment, repair. - Edition first. - M.: MP "Symbol-R" with.

2. Katsnelson N., Spielman E. "Horizon C-257". Mod4, # 9, p. 24-28.

GF generator on K531GG1.

20 - 60 MHz, sinusoidal signal. Perestroika 28 MHz / Volt

Radio №10 2000.

Bug. GCC control device (and detector heads) R№ 6 1997

Simple swinging frequency generator

One of the most universal devices - Oscilograph gets an increasing distribution in home radio laboratories

The industry produces a relatively inexpensive oscillating, designed specifically for radio amateurs, such as N-313, IML-76-2. Oscilograph N-313. has a bandwidth from direct current before 1 MHz and sensitivity 1 mV. For division. OsciLograf OML-76-2. Sensitivity is an order of magnitude less 10 mV for division, but the bandwidth is noticeably wider - to 5 MHz. Both devices have a calibrated scanning, external and internal synchronization.

With these oscilographs, almost any amateur radio constructions can be established. If the radio amateur is engaged in the design of the receiving or transmitting equipment, then the natural satellite of the oscillator will be the swinging frequency generator GKCH.

This, of course, is not an essential device (avometer, the simplest signal generators), without which it is impossible to configure even simple raduitative structures. But just GKCH Allows you to significantly simplify and speed up the establishment of equipment. Moreover, in some cases, for example, when configuring focused selection filters ( FS.) or quartz filters ( Kf), without GKCH It is almost impossible to get satisfactory results.

Describes GCC, proposed B. Stepanov, It is designed for collaboration with any oscillograph that has a sawdust voltage output from the sweep generator. Oscillars that do not have such a way out are not difficult, as it will be shown later on the example of oscilloscope H313., upgrade to be possible to use them with the described GKCH.

GKCh ( fig. one It consists of a high-frequency generator itself, which is assembled on the transistor V1, and the emitter repeater on the transistor V2. The HF generator is made according to a scheme with a common base. Its operating frequency is determined not only by the inductance of the coil L1 and the capacitance of C2-C4 capacitors, but also the output conductivity of the transistor V1, which has a capacitive nature.

Fig. 1. Scheme of the GCC

The average frequency of GCC is installed by the C4 Capacity Condenser " Average frequency", And for frequency modulation of the signal, the dependence of the output conductivity of the generator transistor from the collector current is used. That is why there are no special elements in this GCC, which are introduced for the implementation of frequency modulation (varicaps," reactive "transistors, etc.).

Everyone who had to design equipment on transistors, knows about the effect of their work on the characteristics of cascades containing oscillatory circuits (generators, resonant high frequency amplifiers). This influence is primarily caused by the dependence of the collector capacity p-N. Transition from voltage attached to this transition, or from current flowing through it. Sometimes the effect of the mode of operation of the transistor on the characteristics of the corresponding cascade is easy to remove: it is enough to introduce stabilization by the supply chains of this cascade. In cases where changes in the mode of operation of the transistor are used for any adjustments (for example, in the AGC system), such stabilization is already impossible, to eliminate this effect you have to resort to special measures.

Well, what will happen if changing the mode of operation of the transistor, for example, the GF generator controlled? This can be done by adjusting the offset voltage based on the generator transistor. It is obvious that the generation frequency will be changed, but since these changes are determined by no longer random factors (the discharge of the battery and so on), then the generator controlled by voltage. This is the generator used in the described GCC.

Dependence of collector capacity p-N. Transition SKB. from current collector IK. With a fixed value of the voltage between the collector and the base, you can approximately submitted to:

Value n. Depends mainly from the technology on which the transistor is made. For low-power transistors Values n. can lie within 2-3 . From the above formula, it can be seen that the transition capacity collector-base increases with an increase in the current collector.

The modulating signal is a sawdust voltage from the oscilogram sweep generator - enters the transistor circuit V1 through the connector X1. The amplitude of this voltage and, therefore, the value of the deviation of the output signal of the GCC can be adjusted by a variable resistor R2 " Deviation".

On the transistor V2, an emitter repeater is made, which makes it possible to eliminate the effect of load on the frequency of the generated oscillations. The bias voltage to the transistor V2 is supplied from the emitter circuit of the transistor V1 through the R6 resistor. This resistor establishes the maximum amplitude of the output signal of the GCC. On the output connector X2 The high-frequency voltage comes through a variable resistor R9, which is adjusted by the amplitude of the output signal of the GCC.

The generator of the swinging frequency from the voltage source nourish 9 B. (Two batteries 3336L). The average frequency of the GCC can be changed within 450-510 kHz. Maximum deviation of the output frequency 50 kHz. The unevenness of the amplitude-frequency characteristic of the output signal of the generator does not exceed:

· 0.8 dB. - Under Deviation 12 kHz

· 1.1 dB. - Under Deviation 25 kHz

· 2 dB. - Under Deviation 50 kHz.

The maximum amplitude of the output voltage of the GCC is not less 0.2 B. at load 75 Ohm.. It can be adjusted smoothly and steps (with a remote divider to reduce 10, 100 and 1000 times).

The swinging frequency generator is mounted in the housing with dimensions of 150x100x100 mm made from duralumin. Most of the GCC details are located on pCB. This board and diagram of the connections are shown on fig. 2.

Fig. 2. Printed payment

The circuit board is designed for the following details: resistors - MLT-0.125 or MLT-0.25. Capacitor C5 type K50-6. Capacitors C2, C6 and C7 type MBM or BM-1. Capacitor CSO-2 type CSO. Resistors R2 and R9 type SPO-0.5 or SP3-4A. Capacitor C4 is a rapid condenser with an air dielectric CPV-100 with an elongated axis.

The inductor (L1) filter plugs on the frequency is applied to the GCC 465 kHz from the receiver " WEF-12."Here you can use any inductance coils (homemade or from transistor and lamp radio receivers), resonging at frequency 465 kHz When capacitance of the capacitor in the circuit 200-300 PF.

The size of the GCC housing allows you to apply widely displaced dual capacitors of variable containers with an air dielectric maximum capacity 240-390 PF (from small-sized transistor receivers). In this case, only one section is used, successively with which includes a capacitor with a capacity. 150-200 PF. High-frequency connectors X1 and X2 - CP-50-75F or unified RF connectors from televisions. Power switch S1. - any type.

Especially it should be said about the replacement of transistors V1 and V2. In GCC, you can apply almost any transistors of the MP39-MP42 series. When using transistors of other types, transistors should be preferred, boundary frequency whose generation is slightly (no more than in 3-5 times) exceeds the operating frequency of the GCC. Capacity of the collector transition from higher frequency transistors will be small, therefore, it will be insignificant and its effect on the operator operating frequency. With such transistors, it is impossible to get a significant frequency deviation in GCC.

Note immediately that for normal operation of the GCC, made on the transistors of the structure p-N-P, It is necessary to supply an increasing sawture on it from the sweep generator. Only in this case, the picture on the oscillage screen will have a natural look - the frequency increases when the beam moves from left to right. Indeed, with increasing voltage, the collector current of the transistor will decrease - a positive voltage coming to the base of the transistor structure p-N-P, closes it. This leads to a decrease in the transition capacity SKB. (See the formula previously given) and, therefore, to an increase in the generated frequency.

Respectively for the GCC on the transistors of the structure n-P-N It is necessary to serve an incident saws voltage from the generator. It should be noted that it is such a tension that is derived in oscilloscope C1-19, so if the GKC is designed to work with it, the device should be performed on the transistors of the structure n-P-N Type MP37, MP38By changing the polarity of the power on the electrolytic capacitor and the power supply.

Before proceeding to the description of the establishment of GCC and working with it, you need to make several comments on the use of oscillating as a registering device when working with GCC. Most of the modern oscillats (including the Oscillars mentioned at the beginning of the article H313, IML-76-2) have a bandwidth of the channel of the vertical deviation of the beam over 500 kHz - Maximum output frequency of the GCC. That is why the measuring installation can be significantly easy to simplify, refusing the detector head used in such devices and a special label formation device. Work without detector head has a number of advantages.

Firstly, the sensitivity of the device increases significantly, since the oscillograph can be measured by the signal amplitude from Milvololt units. For detector heads such small levels are essentially unavailable. Yes, and at high levels, the direct registration of the signal to the oscillator is more profitable, since the coefficient of transmission of the detector is always less than one. All this expands the capabilities of the device, allowing, in particular, to observe without additional amplifiers, the characteristics of filters having large attenuations.

SecondlyWith direct registration it is easy to count the amplitudes of signals using a linear mesh on the oscillage screen and its attenuators. This is not always possible when using a detector, since its transmission coefficient depends, as is known, on the level of the input signal.

The input container of the oscillage and the container of the connecting wires can reach in the amount of hundreds of PF. When measuring B. resonant chainsWhen the oscilloscope must be connected directly to the oscillatory contour, it can significantly affect the results. In such cases, the oscilloscope should be connected to the trimmed circuit through the capacitor 10-20 PF. In this case, the sensitivity of the device is reduced in 3-10 Once, but still remains sufficient for most measurements.

To form a frequency tag on the oscillating screen, a method based on characteristic pictures, which occur when two oscillations with close frequencies are added. The resulting oscillation reminds in this case the oscilogram of the amplitude-modulated signal depicted on fig. 3A. (Strictly speaking, it corresponds to an amplitude-modulated signal with a depressed carrier). A similar result follows from the formula trigonometry well known for textbooks for the addition of two angles sinuses, which for two oscillations with frequencies f1. and f2. Can be written in the form:

The lowest ("modulating") frequency is determined by the sedimentality of the initial frequency of generators. Therefore, if one of the frequencies varies in time, then the "modulating" frequency will change. The picture in this case acquires the view shown on fig. 3b . Here point BUT corresponds to the moment when the frequencies of both oscillations are equal.

Fig. 3. Types of oscilogram

In fact, the result of the addition of two oscillations also depends on their initial phases, which was not taken into account in the simplest formula. That is why the actual oscilogram of the addition of two generators (GCC and fixed frequency) signals may look like on fig. 3V. . It may have any other kind of intermediate between these two limit options ( fig. 3g ).

Moreover, in real devices, the initial phase of the oscillations of the GCC is usually varied from one swing cycle to another, so the oscilogram is "overflowing" between the two above limits (for example fig. 3g ). It is visually perceived, as if the oscillations are "run away" to the point BUT Or "scatter" from her. However, in all cases, the picture remains symmetrical about this point, so the point BUT (i.e., the point corresponding to the sum of the coincidence of the frequencies of two generators) is always determined uniquely. This allows you to use it as a frequency label on the oscillage screen, without resorting to any additional forming devices.

Now, when it is known how to get the frequency tag on the oscillage screen, you can move to the establishment of the GCC.

Building GCC and working with him

Initially, with a small deviation (the R2 resistor engine is closer to the bottom according to the resistor's output circuit), the rebel of the coil L1 is set to the desired frequency range. If it is less necessary, then you should either establish a C3 capacitor of a smaller capacity, or apply variable condenser C4 with a large overlap of the tank. The maximum deviation is set by the selection of the resistor R1 (the condenser rotor should be in the middle position, and the R2 resistor engine is in the upper position). In order for the frequency label to be fixed when setting up the GCC clearly, the amplitude of the GCC signal and the rolled generator, according to which the GCC is calibrated ( G4-1, g4-18a etc.), should be approximately equal.

R1 resistor denomination can differ significantly from fig. one Depending on the output voltage of the oscilograph of the oscillator, with which the GCC is used. The resistance value given in the diagram corresponds to the amplitude of the sawtooth voltage around 80 B.. The capacitance of the C1 condenser and, naturally, the resistance of the resistor R1 depends on the lower limit of the swing frequency. With the numbers listed on the diagram of these elements, it is approximately 20 Hz. If, during the selection of maximum deviation, it is necessary to install the R1 resistor with a smaller value, then to maintain the same lower boundary, the swing frequency should be proportionally increased by the capacitor capacitor C1. At the last stage of establishing the selection of the resistor R6, the required value of the output signal amplitude is set.

As already noted, this GCC can also be used with oscillage, which have no power supply voltage from the generator of the Razvert. But for this such oscillating should be somewhat modified.

Fig. 4. Placement of a capacitor in oscillograph H313

To eliminate the effect of wires connecting the GCC with an oscillating, to work the latter in normal mode, eliminate the possibility of damage to its output stage, it is advisable to transfer a resistor R1 and the C1 capacitor to transfer directly to the oscilloscope. In oscilloscope H313., for example, C1 (MBM) capacitor or a similar working voltage at least 160 B.) Install on a small mounting rack ( fig. four ) Near the transistors of the output cascade of the beam horizontal rejection amplifier.

To attach this rack, you can use one of the screws fastening the sweep fee to the oscilogram case. The capacitor body is desirable to cover with insulating material (sticky ribbon or simply paper) so that the capacitor does not accidentally block the contacts of the mounting rack. One of the conclusions of this capacitor is connected to the connector (it is installed on the rear wall of the oscillage), and the other - through the R1 resistor with one of the outputs of the two-stroke amplifier horizontally the beam deviations. Which outputs should be connected with GCC, it is determined, as noted, the structure of the GCC transistors.

In the study specific devices (filters, UPUs, etc.) The signal for the formation of the frequency tag on the oscilograf screen is fed from a quartz generator or GSS. They must have smooth adjustment of the amplitude of the output signal. This signal is fed to the oscillage input through the unleashing resistor resistance at least 100 com or capacitor with no more 10-20 PF. The amplitude of the GSS signal is selected experimentally, increasing it until the label becomes clearly pronounced ( fig. 3d ). The acceptable point of reference is obtained if the amplitude of the tag is 2-4 mm. Obviously, the larger the size of the oscillage screen, the more the image of the useful signal and the less the oscilogram distortion will be visible due to the label.

Since the image of the amplitude-frequency characteristic is symmetrically relative to the horizontal axis, to increase the accuracy of the amplitude and frequency counting and frequency, it is advisable to shift the image so that the "zero line" (symmetry axis) accounted for the lower boundary of the mesh on the oscillage screen ( fig. 3d ).

The yield of GCC has a direct (galvanic) connection with the general wire, so the signal to the test cascade can only be supplied through a separator capacitor with a capacity of at least PF. Sometimes there is a need to apply the signal directly (not through the communication coil, which is consistent with the cascade, etc.) to a parallel resonant contour. In this case, the capacitance of the capacitor must be small - at least once 20 less than the capacitance of the capacitor included in the oscillating circuit. Otherwise, this circuit will be drawn by a small output resistance of the generator.

When performing measurements in the UPU, it is important to constantly check whether the device under study is not overloaded. The fact is that due to the selective properties of the resonant contours, the output signal during overloads is close to sinusoidal. Overload is manifested only in the apparent "expansion" of the bandwidth of the amplifier and in the "reduction" of its unevenness. That is why in the process of working with the GCC, you should always pick up this level of the GCC output signal to maintain a linear connection between it and the output signal of the device under study. Such control must be carried out continuously in the process of establishing the amplifier.

We will illustrate the work with the GCC on the example of optimizing the load resistance of the piezoceramic filter FP1P-011. Measurement scheme is shown on fig. five.

Fig. 5. Measurement scheme when optimizing the load resistance of a piezoceramic filter

From a swinging frequency generator G1. The signal through the coarse resistor R1 enters the filter studied Z1. This filter is loaded to the variable resistor R2. The signal from the filter through the separation capacitor C1 enters the oscillage input U1.where it is also supplied (through the C2 separator capacitor) signal from the GSS. Filter input resistance (by passport data) 2 com. It is so that the resistance of the R1 resistor is also chosen, since the output resistance of the GCC (it must be taken into account when applying filters) significantly less than this value and is approximately 50 Ohm..

On the fig. 6. Achli filter is shown during three different load resistances. Curve 1. corresponds to the case when R2 \u003d 1 com (Passport value of the output resistance of the filter), curve 2. - 10 com, but curve 3. - 100 com.

The numbers listed near these curves denote the filter bandwidth in terms of 0.7. Comparison of these three curves shows that, though R1 \u003d 1 com It fully complies with the technical conditions, an increase in the resistance of this resistor has improved not only the form of Ahh, but also significantly reduced losses in the bandwidth.

Fig. 6. Amplitude filter characteristics

The linear amplitude characteristic of the channel of the vertical deviation of the oscillage is not always convenient in practice. If the vertical deviation path has a small overload capacity (i.e., the image cannot be output from the screen vertically), then the real observations of the frequency response only at the level -20-30 dB.that in many cases is not enough.

The output from the position may be administered to the measuring installation at the inlet oscilograph of the logarithmic amplifier ( fig. 7. ).

It is an ordinary broadband amplifier on the V3 transistor with a logarithming diode chain in the negative chain feedback (Diodes V1 and V2). This device provides a practically logarithmic dependence of the output signal amplitude when the input amplitude is changed within 3-3000 meters. Amplifier operating frequency range extends from 30 kHz before 1 MHz.

Fig. 7. Logarithmic amplifier scheme

Selecting the enhancing channel of the vertical deviation of the oscillage, one can calibrate its grid directly in decibellah. The input resistance of the logarithmic amplifier is approximately 1 com, Therefore, it is advisable to establish an emitter or source repeater at its input. The signal from the GSS in the measuring unit with such an amplifier should be supplied to the oscillage input, and not to the amplifier input.

Replacing the L1 coil ( fig. one ) and proportionally reduced the capacitance capacitor C2 and C3, the operating frequency of the GCC can be increased to 3-7 MHz (This largely depends on the parameters of a particular instance of the transistor used as V1). In general, by applying the considered frequency control method, using the appropriate transistors, it is possible to implement the generators of the swinging frequency on the most different frequencies, up to the microwave.

The appearance of the design of the GCC is shown in the photo at the beginning of the article.

B. Stepanov. "Radiozhomnik" 1983

Need a simple GKC scheme to set up PDF

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1. It seems that works
just did not cost and without flaws. Pretty weak scope of the output signal. The detector head is unable to recognize anything even at the maximum sensitivity of the oscilloscope. You have to build a two-chain amplifier ... Another disadvantage is too small frequency deviation. I went through all the varicaps available for me, but I could not get a strip wider than 300 kHz ...
here is the ultimate scheme with electronic setup. The L1 coil contains 12 + 4 turns wound on the Chinese frame of ferrite dumbbell and adjustable pot.

all nuances of stabilization of amplitude on such a scheme are painted in Radio №2 1984, pp 22 "amplitude stable heterodyne" Low amplitude - because the signal is removed from the outlet of the contour. On the contour with the amplitude, everything will be ok. I did a similar scheme but for other purposes. The signal directly from the contour was submitted to a repeater on the bevel.

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Radio Affectory Units GF Generator
I propose a GWC scheme with increased stability (Fig. 1). It has large input and output resistances and a smaller output capacity than the standard inductive three-way. Transistors are included according to the "Common Stoke - Shared Base" scheme, VT1 is a lodge for junction. The output voltage of the generator - 0.1 ... 0.2 V. The collector of the VT1 collector can be enabled (required via the resistor 50Ω) the surplus circuit configured to the main frequency or harmonic. Possible options The inclusion of the main circuit is shown in Fig. 2. Capacitor C2 can have a capacity of the order of picophade units. The R2 engine is set to the lower position position and moved to generation at the lowest circuit frequency, to obtain a harmonic engine installed above. If stability is not as important, and uniformity of amplitude is needed, the complete inclusion of the contour is used. On the LC ranges, it is shunted by a resistor of a magnitude of a somewhat kilome.

Deploy a full screen

Deploy a full screen

Option output amplifier

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and industrial quartz filter FP2P-00307M 10.7M-15-in from a broadcast receiver.

1. Log. The detector is taught from NWT very well proven.
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well, or quite simple

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Working with schoolchildren for many years, I know that I know that almost every student dreams of communication. And the mobile phone here is just nothing. Another thing is that modern designs for beginners have a lot. True, you need to admit that they are just not for beginners. And the time is 6p3c already gone. So how to satisfy hunger on simple transmitters? I think there is no need to say that advice to buy aik or even UW3DI is absurd. For a twelve-year-old teenager, this option will not be considered (perhaps the dad - the radio amateur will take something). In the literature you can find a variety of radiomicrophone schemes. But only a man inext may think that they can work. Frequency instability, external tip, random nutrition reduce the simplicity of the scheme and ... disappointment is sometimes for life. In order to still satisfy interest in transmitters - toys working for a distance of several tens of meters (and other requirements of the guys, as a rule, do not put) and a simple design of the weekend is developed - the transmitter "regatta", the laureate of several exhibitions of creativity Radio amateur - Mariupol designers.

The finished node of the standard TV is used as a specifying transmitter generator - the SK-M-24 meter wave selector unit. Let me remind you that the selector is a frequency converter of meter wave channels consisting of two subbands 1-5 and 6-12 television channels. This transmitter uses the first of the subbands (1-5 channels). The frequency spectrum of the received signals is 48.5 ... 100 MHz. The heterodyne of the block at the same time overlaps the frequency range by 38 MHz above, i.e. 86.5 ... 138 MHz. Thus, to obtain the frequencies of the FM range of 100 ... 108 MHz, it suffices to use the frequency of the heterodyne as a specifying generator and the transmitter is ready. This requires minimal alterations. In the SCM-M-24-2 block diagram, the transistor VT5 performs the function of the heterodyne of this subband, and the mixer VT3 is required to be transferred to the heteroodine signal amplification mode 100 ... 108 MHz. To do this, in the coil L 21, unnecessary turns are required, leaving 8 turns from the available 24. To output the generator signal, a connector of the PC output unit "is used, with an additional C9 condenser included in the gap (Fig. 1). For overlapping the desired section 100 ... 108 MHz on the output 4 of the SC-M-24 block (setting) must be submitted adjustable voltage in the range of approximately 5.5 ... 8 V. on the diagram Fig. 1 For this purpose, an R8 variable resistor is used, and the frequency adjustment limits can be adjusted by the selection of resistors R7 and R9. To modulate the audible signal, an amplifier on the transistor VT1 is used, the signal from which through the level controller is mixed into the frequency rearrangement voltage (output 4 blocks SC-M-24). When using a dynamic microphone, you can do without a microphone amplifier. Frequency modulation is obtained by changing the container of the container of the heterodyne under the action of the beep. The microphone is connected to the outputs 1 and 2 xs1, and the signal from the tape recorder comes from the conclusions 3 and 5 xs1 (the output 2 remains common) through the voltage divider R1, R1-A, R5.

The output Socket of the PC is used to connect an antenna, which can serve as a piece of 1-1.5 meters long. A receiver can serve any receiver with FM - range. This design can help with the organization of various competitions as a "shore" of the referee, as a kind of broadcast in children's recreation camps, etc. The quality of the signal, frequency stability and modulation is high enough.

The receiver is designed to receive sound maintenance of MB television channels and DMW ranges. Despite wide opportunities It is very simple, both in manufacturing and in the selection of parts. The scheme is based on the VKM-FM radio receptacle on the KS1066H1 microcircuit (from the Radiolection purchased in the store) and two SCM-24 selectors and SCD-24 from the old domestic television. A plus, pulse source Voltage + 33V to configure the ranges. Three ranges (MV1, MB2 and DMV) are switched by a mechanical switch, and the smooth adjustment, using a multi-turn variable resistor (resistor setting up from a radioco receiver).

SCM-24 and CCD-24 channel selectors are included according to the television scheme. Switch S1 select the range. No system ARU, it replaces the R1 / R2 divider giving 8V at the output 6 SCM-24 and 4 CCD-24

The receiver is powered by a 12V voltage to receive the voltage required to configure selectors to the channels use a pulse source on the D1 chip. The multivibrator on D1 generates pulses with a frequency of about 70 kHz. These pulses come to the transistor key on VT1, in the collector of which the inductance L1 is included. At the inductance, "pumped up" about 50V, then this voltage is straightened by the VD2 diode and smoothes with the C10-R6-C8 filter.

Stabilitron VD1 stabilizes voltage at 33V. Such a source allows a load current up to 5 m with a stable output voltage. This is more than enough to normal configuration of selectors.
The K1555LA3 chip from the source voltage 12V through the R8 resistor, quenching the excess of the voltage.
The settings organ is a multi-turn variable resistor R5.

The power supply voltage from the output of the SCM-24 / SCD-24 selector system enters through the C4 capacitor to the input of the VHP-FM of the receiving path made on the AT microcircuit. This scheme is based on the receiving tract of the VHF-FM receiver from the Radiolection purchased in the store. The difference of the scheme from the radio confinement scheme is that the VARACAP and resistor settings are excluded, and instead of the volumetric coil of the heteroodine, the coil of the PCH contour from the TV 3-USL (from submodule CMRK-2) is installed.

This L2 coil on the TV it works on a 100 MHz Popinial, here the circuit frequency on it is reduced to 31.5 MHz by replacing the contour capacitor 82 PF capacitor 91 PF to install a new coil in the radioco board, four additional holes for the conclusions of the coil frame are drilled. Installation and fastening - by pressing and soldering on these contacts from the side of the press.

Additionally, a parametric stabilizer on the VD3 stabilion VD3 is introduced into the VD3 stabilion, which reduces the supply voltage A1 to 5 V. L1 coil is wound on a ferrite ring with a diameter of 12-15 mm, it contains 250 turns of the PEV-0 wire.

The receiver is operational after the first inclusion. Establishment lies in the adjustment of the L2 coil by best quality reception. During this, you need to remember that the L2-C17 circuit setting changes the entire setting of the receiver, and therefore, adjusting the L2 you need to hold the setting on the TV channel, turning a slightly handle R5.