Simple transceiver for a range of 160 meters
A beginner radio amateur who has no experience and wants to build a HF transceiver with his own hands is faced with the problem of choosing a simple and reliable design.
This is usually a transceiver direct conversion Polyakov, various versions of "radio - 76" or Pogosov's transceiver. The abundance of winding units on ring and armored ferrite cores often becomes an insurmountable obstacle for a beginner. And assembling such a simple Pogosov transceiver can turn into a fruitless search for such a "rarity" as 6P15P. This has been verified by my own experience. In the end, out of a dozen extracted lamps, only two turned out to be operational. With one of them, the output power of the transmitter was 0.8 watts, with the second 1.5 watts (measured with an M3-3A wattmeter).
Then there was an idea to try to assemble a completely transistor version on the basis of Pogosov's transceiver from a pair of old transistor radio receivers and a reel-to-reel tape recorder. Details that cannot be discarded in order to maintain acceptable transceiver parameters are the EMF and a 500 kHz crystal resonator. The result is a very simple design. All parts are taken from old household appliances.
Power amplifier schematic diagram
Transceiver, power amplifier and power supply are made in separate units. A power supply of any design capable of providing a stabilized voltage of 24 volts at a current of 200 - 300 mA for powering the transceiver and 24 - 28 volts at a current of at least 3 A for powering a power amplifier (for the latter, it is possible not to stabilize, but at the same time the power of the output stage of the transmitter will decrease by 30 - 40%). The quiescent current of the final stage of the power amplifier 100-200 mA is selected by the resistor R7, depending on the used transistor.
It is convenient to mount the transceiver and power amplifier in the cases of old car radio tape recorders or radio receivers.
The power amplifier board is mounted on a radiator, to which VT2 is directly attached and through an insulating VT3 gasket. Parts on the board are mounted from the side of the conductors. Coil L1 - power amplifier is wound on a textolite or ceramic frame with a diameter of 16 mm. wire PEV - 2 0.45 mm.
For the manufacture of the TR1 RF transformer, ferrite cylinders from the IF circuits of transistor radio receivers are used. Sections of a brass tube with an outer diameter of 6.9 ... 7.1 mm are used as a secondary winding. (knee from the telescopic radio antenna). Primary winding transformer contains 3 turns of MGTF wire 0.6 mm. (see drawing). Dr1 is wound on a similar ferrite cylinder and contains 15 turns of wire PEV - 2 0.8 mm.
As the VFO circuit (L1), a radio receiver local oscillator circuit ("VEF", "Ocean", etc.) of the medium-wave range is used, tuned to the frequency of the amateur range (1330 - 1500 kHz or 2330 - 2500), depending on the used EMF.
L2 - IF circuit from any transistor radio receiver (domestic with an IF of 465 kHz or some imported ones with an IF of 495 kHz) tunable within the range of 500 - 503 kHz. To do this, it is enough to replace the ferrite core of the circuit with a core from the circuits of the HF ranges or wind up part of the winding turns.
The bandpass filter coils L3 and L4 are wound on sectioned frames from the IF circuits of transistor radio receivers (Ocean, VEF, Veras, etc.) and contain 50 turns of 0.25 mm PEV wire. Branch from the 10th turn "from the bottom".
Details and possible replacements:
in the transceiver VT1, VT5, VT8, VT9, VT10, VT11 - KT315; VT2, VT3 - KT361; VT4, VT13 - KP303, KP307; VT6, VT12 - KT608, KT603, KT646 with any letter indices; VT7 - KT3102A, B, C, KT315V, G. VD1 - D818G, D, E; Resistors R32, R24 - 0.5 W, the rest 0.125 W; capacitor C28 of any type. In the GPE, it is desirable to use capacitors with a minimum TKE, the rest of any type.
in the VT1 power amplifier - KT603, KT608, KT646 with any letter indices; VT2 - KT904B, KT606A, B, KT801A, B (on an insulated radiator). Resistors: R6 - 2 W, R7 - 0.5 W, the rest 0.25 W. Capacitors: C9 of any type with an air dielectric (for example, from VEF, Alpinist, etc.); C4, C7 - MBM for a voltage of at least 160 volts; С3, С5 - КМ of any TKE group; C8, C10 - KSO - 1; C6 for a voltage of at least 63 volts; the rest of any type.
Relay RES 22, RES 32 for an operating voltage of 24 volts.
Main board and wiring
Power amplifier circuit board
The technical characteristics of the transceiver practically do not differ from those described in.
The transceiver has been in operation for over two years, both in stationary and in the field. During this time, more than 2500 QSOs have been made. all correspondents note high quality signal.
Literature:
- Pogosov. A. - A simple transceiver for the 160-meter range. - To help the radio amateur. Issue 99. Publishing House DOSAAF USSR. 1987
- Sushkov. C. - Tri-band transceiver. - Radio 1992 No. 6 p. 9-11. Radio 1992 No. c. 8-11.
- Temerev. A. - Transceiver "Amator-160". - Radio 2001. No. 9 p. 58-61.
- Andryushchenko. B. - Broadband power amplifier. - Radio 1984 No. 12. p. 18-19.
Gerbutov. A. (RZ6APH). Gerbutov. B. (RK6AQP)
Supplements and answers to readers' questions from the authors RK6AQP and RZ6APH.
We have carefully read the reviews about our publication and we apologize for the incomplete data of the L1 P-circuit coil. It contains 28 turns of PEV-2 0.45 mm. on a frame with a diameter of 16 mm. without core.
Now we will try to answer the questions.
It is highly controversial that the new EMF, the parameters of which a novice radio amateur is unlikely to be able to test, will be more efficient than the EMF purchased on the radio market. Surely it is soldered out of industrial communication equipment that has reliably worked for more than one year. In all transceivers assembled according to this scheme, just such old filters were used. different types and designs.
We give the winding data, which still have to be corrected empirically (L1 GPA), depending on the applied EMF to the upper or lower side stripe.
L1 (GPD) - 4 sections with 20 turns of SEV with a diameter of 0.12 mm. core Ф600. L2 (UPCH) - 3 sections with 60 turns of PEV with a diameter of 0.1 mm. core Ф600. The data of the bandpass filter coils are taken from the description of the "Albatross 3" transceiver (author V. Sushkov. Radio magazine No. 7 1992) and have no differences from the author's version either in design or in tuning.
Not one of the manufactured transceivers had problems with self-excitation of any cascades.
Any type of relay can be used in the transceiver. In W.M. relay contacts K2.2, K2.3, K2.4 must withstand a total current of at least 3 A.
You can also use a reversible stage on a field-effect transistor, but in this design, VT7 works only during transmission. The use of UHF during reception inevitably leads to the need to turn on an additional bandpass filter at the input and introduce AGC due to a sharp increase in sensitivity. All this negates the simplicity of the design.
Those wishing to experiment with the circuit can introduce an additional amplifier, the simplest attenuator, S - meter, etc. An AGC circuit from the same Pogosov design can be connected to the additional amplifier circuit without any changes.
A few words about the output stage. The KT803 transistor is more often found in household equipment ("Saturn 201" reel-to-reel tape recorder, "Odyssey 001" amplifier, etc.). In addition, the use of a mid-frequency transistor excludes self-excitation at high frequencies. KT803 (fgr = 20 MHz) in the 160 M range works better and more reliably than KT903. Depending on the desire and capabilities, you can use almost any transistors that are suitable in frequency and power characteristics, with a corresponding correction of the operating mode. We tested: KT903A, KT907A, KT907B, KT9116B, KT922V, KT926A, KT930A, KT931A, as well as low-voltage KT920V. But we repeat, this will no longer be called a simple and inexpensive transceiver for a novice radio amateur. We do not pretend to invent some kind of universal super - design. A simple device for the first QSOs and nothing else. There are many more complex designs with higher parameters.
In conclusion, about nutrition. It is possible to convert the transceiver to 12 volts, but in stationary operating conditions the supply voltage does not matter, and in field conditions it makes no sense to use 12 volts to power the transceiver when the U.M. you still need to supply at least 24 volts when using non-scarce high-voltage transistors (KT803, KT903) in it to obtain Pout = 10 W.
A lot of letters come to our E - mail with questions about how to enter the 80 and 40 m bands into the TRX-13 transceiver. To do this, the PF must be taken out of the main board. PF data are the same as in the transceiver "Albatross" (radio 1992 No. 6, No. 7.). Coils for the ranges of 80 and 40 m are performed on frames from the IF circuits at 10.7 MHz (from the Riga 103 radio receiver), they contain respectively 35 (tap from the 8th) and 25 (tap from the 5th) turns PEV wires 0.25 mm, these coils can also be made on frames with a diameter of 7 mm, from contour coils to HF. ranges of any other radio receivers.
In the UM, the P-loop coils are wound on frames with a diameter of 16 mm, with a PEV wire of 0.8 mm, for 80 m - 17 turns; 40 m - 9 turns; C8: 80 m - 3500 pF, 40 m - 1600 pF. C10 only switches on at 160 m.
GPD also needs to be replaced with a more serious design, for example, such as in TRX "Amator - EMF - U" (Radio Hobby 2000, No. 5) or another. We took as a basis G. Petin's generator (RADIOLUBITEL 7/97, p.34.)
The setting and design of the GPA circuits has no peculiarities. Coil data can be taken from the Amator - EMF - U transceiver. Or L1 - 50 turns, L2 - 35 turns, L3 20 turns on a frame with a diameter of 7 mm (from receivers "Veras", "Ocean", etc.) to 0.25 mm PEV wires. Capacities of capacitors C2 - C10 are selected individually when setting the range boundaries.
Attached are photographs of the TRX-13-3 tri-band transceiver, which we are working on at the moment. Please don't be alarmed, this is our "testing ground".
And this is what a three-band PA looks like on KT 803A
Bulgarian version of the previous transceiver for 80 and 40 meters
Range: 3.7 and 7 MHz
Receiver sensitivity: 5 - 8 μV
Output power: 15W at 28V and 8W at 12V
Power transformer from the tape recorder "Jupiter-202"
Appearance main board
Main board schematic
Local oscillator circuit
Local oscillator appearance
Band pass filters
Appearance
Instead of the ULF chip TDA7052, you can use the ULF on the more affordable TDA2003
Quartz filter application
There was a time, I was fond of radio communication on the HF band, 160 and 80m, but when I moved to the city, I put all this on the upper shelf due to lack of time and place where to deploy the antenna, although the 160-meter range "died out". At one time, I received permission for 25 hryvnia with the callsign UU5JPP.
But it still pulls to go on the air, and then I began to surf the Internet to look for new transceiver circuits, and came across this circuit, which will be discussed, which the author of this circuit will tell about.
Somehow there was a desire to make an SDR transceiver. And the search for information and diagrams on SDR transceivers began. As it turned out, there are practically no complete transceivers, with the exception of various versions of the SDR-1000. But for many, this transceiver is both expensive and difficult. Various versions of the main boards, synthesizers, etc. have also been published. ,those. separate functional units. Tasa YU1LM made a lot in the field of development and popularization of simple SDR technology, which also made a complete “AVALA” transceiver, and we can recommend its designs for beginners in this field and who want to try what SDR is with minimal costs.
In the end, I decided to make my own, as simple and at the same time, high-quality SDR transceiver. During the development, materials from YU1LM and other publications were used. It was decided to make the mixer on the 74HC4051 - once made a direct conversion receiver by Sergei US5MSQ, with a mixer on this microcircuit. And the use of the 74HC4051 in a transceiver makes it possible to make a very simple mixer - common for both the receive and transmit paths. The quality of this mixer is quite satisfactory.
The transceiver is built according to a direct conversion scheme from an operating frequency to an audio frequency for signal processing by a computer sound card .... Therefore, much that has been written about the direct conversion technique applies to SDR as well. In particular, the need to suppress the inoperative sideband (in the SDR mirror channel) by the phase method.
- Operating frequency range 14.140 - 14.230 MHz. (When using a crystal resonator with a frequency of 14.185 MHz and sound card with a sampling rate of 96 kHz)
- The sensitivity is about 1 µV and strongly depends on the quality of the sound card.
- The dynamic range for intermodulation is more than 90 dB - there was nothing more to measure with.
- The carrier suppression for transmission is more than 40 dB (I got 45 - 60 dB) and depends on the specific instance of the 74HC4051, as well as on the quality of the setting.
- Suppression of the image channel is more than 60 dB with the correction program.
- The output power is about 5 watts.
It is clear that the SDR transceiver requires control program, and my choice fell on the M0KGK program because of the possibility of the program to correct the amplitude and phase in the entire working range of the sound card and memorize the calibration points. This is very important. This property of the program allows you to suppress the mirror channel very well. Due to the lack of the possibility of memorizing the calibrations at several frequencies of the sound card in the program, he refused to use it - this program works perfectly with SDR transceivers with built-in frequency synthesizers, where frequency tuning is performed by the synthesizer, and not by the frequency of the sound card.
Click on the image to enlarge
The schematic diagram is simple and I will not describe the principle of operation. This can be read from Tasa YU1LM, though in English. No PCB error detected. For the convenience of soldering, I signed the denominations of the elements on the printed circuit board drawing, and not the serial numbers of the elements.
The transceiver practically does not need to be configured, and with proper installation it starts working immediately. With the correct settings of the M0KGK program, of course.
It is clear that many will have difficulties in acquiring a quartz resonator. Therefore, if it is absent or because of the desire to have the entire range of 20 m, you can simply use an external VFO or synthesizer at the operating frequency, the signal from which must be fed to the 1st pin of the 74HC04 through a 10nF blocking capacitor. Do not install capacitors C63 and C64.
It is very pleasant and convenient to work with this transceiver. All computer mouse control. The entire spectrum is visible in the 96 kHz band, and by simply pointing or "dragging" the program filter, we instantly re-tune to the station of interest. Very quickly and clearly. After working on this transceiver, working on an ordinary one, something is already missing - visual information about the situation on the band.
With the spread of the Internet, radio amateurs, no matter how sorry, gradually began to fade away. Where have the army of radio hooligans gone, the legions of "fox hunters" with direction finders and their other colleagues ... There is no mass agitation at the state level and, in general, the value system has changed - young people more often prefer to choose other entertainment for themselves. Of course, Morse code is not often used in the current digital age and radio communication in its original form is increasingly losing its position. However, amateur radio as a hobby is a cross between a sort of romance of wandering with a fair amount of skills and knowledge. And the ability to creak with brains, and put your hands, and rejoice in your soul.
And yet I did not put my brothers to shame,
but embodied their forces of connection:
I, like a sailor, plowed the elements
and, as a player, prayed for luck.
M. K. Shcherbakov "Page's Song"
However, to the point. So.
When choosing a design for repetition, there were several requirements arising from my initial knowledge in the field of RF equipment design - the maximum detailed description, especially in the sense of tuning, no need for special RF measuring devices, available element base. The choice fell on the direct conversion transceiver of Viktor Timofeevich Polyakov.
Transceiver - communication equipment, radio station. Receiver and transmitter in one bottle, and they have a part of the cascades in common.
Entry-level SSB transceiver, single-band, 160m, direct conversion, tube output stage, 5W. There is a built-in matching device for working with antennas of various impedances.
SSB - Single-sideband modulation (Amplitude modulation with one sideband, from the English Single-sideband modulation, SSB) - a type of amplitude modulation (AM), widely used in transmitting and receiving equipment for efficient use of the channel spectrum and power of transmitting radio equipment.
The principle of direct conversion for obtaining a single-sideband signal allows, among other things, to do without specific radio elements inherent in the superheterodyne circuit - electromechanical or quartz filters. The 160m range, for which the transceiver is designed, is easy to change to 80m or 40m by reconfiguring the oscillating circuits. The output stage on a radio tube does not contain expensive and rare HF transistors, is not picky about the load and is not prone to self-excitation.
Let's take a look at the schematic diagram of the device.
A detailed analysis of the circuit can be found in the author's book, there is also the author's printed circuit board, the layout of the transceiver and a sketch of the case.
In comparison with the author's design, the following changes were made to its performance. First of all, the layout.
Transceiver version designed for operation at the lowest frequency amateur band, quite allows a "low-frequency" layout. In its own design, solutions were used that are more applicable to HF equipment, in particular - each logically complete unit was located in a separate shielded module. Among other things, this makes it much easier to improve the device. Well, I was encouraged by the possibility of a simple retuning to 80, or even 40m bands. There, such a layout would be more appropriate.
Toggle switch "Reception-transmission", replaced by several relays. Partly due to the desire to control these modes from a remote button on the microphone sole, partly due to more correct wiring of signal circuits - they no longer needed to be dragged from afar to the toggle switch on the front panel (each relay was located at the switching point).
The design of the transceiver includes a veneer with a large deceleration and, this makes it much more convenient to tune to the desired station.
What was used.
Instruments.
A soldering iron with accessories, a radio installation tool and a small locksmith. Scissors for metal. Simple carpentry tool. I used a milling machine. Blind rivets with special pliers for their installation came in handy. Something for drilling, including holes on a printed circuit board (~ 0.8mm), can be contrived with one screwdriver - specific shawls, few holes. Engraver with accessories, hot melt glue gun. It's good if you have a computer with a printer at hand.
Materials.
In addition to radioelements - mounting wire, galvanized steel, a piece of organic glass, foil-clad material and chemicals for the manufacture of printed circuit boards, related trifles. Thick plywood for the case, small nails, wood glue, a lot of sandpaper, paint, varnish. A bit of polyurethane foam, not thick dense polystyrene - "Penoplex" 20mm thick - for thermal insulation of some cascades.
First of all, in AutoCAD, the layout of both the entire device and each module was drawn.
The modules themselves were made - printed circuit boards, "nests" of the module cases from galvanized steel. The boards are assembled, the contour coils are wound and installed, the boards are soldered into individual casing-screens.
Variable capacitor for local oscillator - with every other plate removed. I had to disassemble and unsolder the stator blocks, then put everything in place.
The body is made of 8 mm plywood, after adjusting the openings and holes, the box is sanded and covered with two layers of gray paint. From the inside, the box is finished with the same galvanized steel and the final installation of the elements and modules has begun.
The gallet switch and variable capacitor of the matching device are located near the antenna connector, this allows the connecting wires to be shortened as much as possible. To control them from the front panel, extensions of their shafts from 6mm threaded rods and connecting nuts with stoppers are used.
The axis of the tuning string was made from a shaft from a broken inkjet printer, on the same axis there was a braking unit, which also came in handy. The groove holding the stringer cable was made with the help of an engraver.
A special pulley, the cable itself and the spring providing the tension are taken from the tube radio.
The tuning knob is made of two large gears from the same printer. The space between them is filled with hot melt glue.
The walls of the local oscillator module are finished with a layer of polyurethane foam, this allows to reduce the "frequency drift" due to heating when tuning to the station.
The module of the telephone and microphone amplifier is placed on the rear wall of the case, for its (module) protection from mechanical damage, there are outlets on the side walls of the case.
Setting up the local oscillator of the transceiver. For her, a simple HF attachment to a multimeter was made, which makes it possible to evaluate the level of HF voltage, for example.
Initially, it was decided to change the transmitter output stage circuit to a semiconductor one, powered by the same 12 V. In the photo above, it is he who is not fully assembled - a milliammeter for a higher current, an additional winding on the P-loop coil, only low-voltage power.
Scheme of changes. The output power is about 0.5 W.
In the future, it was decided to return to the original. I had to replace the milliammeter with a more sensitive one, add the missing elements, change the power supply.
The power amplifier module is thermally insulated from the rest of the structure, as it is a source of a large amount of heat. Its natural ventilation is organized - a field of holes is made into the basement of the case and on the cover above the module.
The basement of the enclosure also contains a number of blocks and modules.
The transceiver circuit has the simplest solutions for individual units and does not shine with characteristics, however, there are a number of improvements and modifications aimed at both improving performance characteristics and increasing convenience during operation. This is the introduction of sideband switching, automatic gain control, and the introduction of telegraph mode during transmission. The suppression of the inoperative sideband can also be slightly increased by reducing the spread in the characteristics of the mixer diodes, for example, by using the KDS 523V diode assembly instead of the V14 ... V17 diodes. Improvement of individual nodes can be performed according to schemes from. It is also worth paying attention to the solutions. The applied layout allows you to do it quite conveniently.
Literature.
1. V.T.POLYAKOV. TRANSIVERS OF DIRECT CONVERSION Publishing house DOSAAF USSR. 1984 year
2. Diagram of an attachment to a multimeter for measuring RF.
3. Dylda Sergey Grigorievich. Small-signal channel SSB TRX'a direct conversion to a range of 80m
When developing the design offered to the attention of readers, the task was to make it such that printed circuit boards could be easily repeated at home, and there were as few scarce elements as possible. In addition, I wanted the transceiver to be fully controlled Power program SDR (http://www.flex-radio.com), which is freely distributed and constantly improved.
The described design of the SDR transceiver frequency synthesizer is based on the AD9854 microcircuit (DDS - direct digital synthesis), which Flex-radio uses in the SDR-1000 transceiver.
Source: Radiomir KV and VHF 2008 5
Yuri Goncharenko, RV3DLX,
town Protvino
Download SDR transceiver with your own hands - Viktor Goncharov
Of course, the circuit can also use a conventional high-frequency npn transistor type KT603, KT646, KT606, but a powerful field-effect transistor works more stably, is less susceptible to the effect of direct signal detection and allows you to increase the output power of the transceiver. The local oscillator frequency is stabilized by a widespread quartz resonator at a frequency of 3579 kHz. You can also use a ceramic resonator.
The variable capacitor allows you to shift the frequency within a small range, which makes it easier to tune to the called station. When using a quartz resonator, the frequency can be shifted by 1.5-2 kHz. If you use two or three quartz, connected in parallel, then the frequency can be changed up to 4-5 kHz.
When using ceramic resonators, the frequency tuning range is several tens of kilohertz.
In the receive mode, the signal from the antenna passes through the low-pass filter L1L2C5C6C7, then through the matching transformer 1: 4, and goes to the drain of the transistor. The channel resistance of the field-effect transistor changes with a frequency determined by the quartz resonator. As a result, the signal of the difference frequency between the receiving and the generated frequencies is isolated at the resistor R3.
Through the blocking capacitor C9, it is fed to the amplifier audio frequency... It can be made on 2-3 transistors or an LM386 type microcircuit. At the ULF input, it is desirable to use a low-pass filter (narrow-band or low-pass), this will significantly increase the selectivity of the receiver.
When you press the telegraph key, the transistor goes into amplification mode. The transformer matches the 50-ohm load (antenna) and the low-pass filter filters out harmonics in the radiated signal. The output power can be up to 6 watts, and the current consumed from the power supply is up to 1 ampere.
The high frequency choke must be rated for a current of at least 1 ampere.
The matching transformer can be wound on a ferrite ring with a diameter of 12-16 mm with a permeability of 600-1000. Winding is carried out with two pre-twisted wires 0.4 mm, twisting pitch 10-12 mm. The number of turns is 10.
After winding, the end of the first winding is connected to the beginning of the second and soldered to the drain of the field-effect transistor.
It is also desirable to wind coils L1 and L2 on ferrite rings of the 20VCh or 50VCh type with a diameter of 10-12 mm.
Field-effect transistor must be installed on the radiator through a mica gasket.
The image below shows possible variant assembled CW transceiver.
As you can see in the photo, the transceiver has a field indicator in the antenna. It is not difficult to do this on several details (Fig. 1, Fig. 2). The transformer is wound on a 20x10x5 ring with a magnetic permeability of 1500-2000. Transformer T1 consists of a loop coil (5 turns *) and a coupling coil (2 turns *).