The ranges are no longer relevant, the common and well-known microcircuit for the FM band 174XA34 is also outdated, therefore, we will consider the independent creation of a high-quality VHF receiver using a modern elementary base - specialized inexpensive microcircuits TEA5711 and TDA7050. Chip TEA5711T in this case in a planar body.
Simplest VHF FM receiver, available for repetition by a novice radio amateur, can be assembled according to the scheme of a single-transistor synchronous-phase detector. circuit diagram such a receiver is shown in the figure.
The signal is received by the WA 1 antenna, the role of which can be played by a piece of mounting wire. This signal enters the oscillatory circuit L1C2, by adjusting the capacitor C2, the circuit can be tuned within the VHF FM range of 65.8-73 MHz. The signal voltage allocated by this circuit is fed through the capacitor C3 to the base of the transistor VT1. This transistor stage performs several functions simultaneously: the functions of a phase detector, a low-pass filter, an amplifier direct current and low frequency amplifier. Phase detection occurs on p-n transitions transistor equivalent to diode junctions. You can assemble the receiver by volumetric installation, or you can develop a printed circuit board based on a circuit diagram, and arrange the parts on it in the same order as in the diagram. Coil L1 does not have a frame, for winding a drill shank with a diameter of 7 mm is taken and a coil is wound on it with a PEV wire of 0.4 ... 0.5 mm. Coil L1 contains 14 turns. After winding, the drill is removed from the coil (it only serves as a winding mandrel).
Transistor P416B can be replaced with GT308A, KT603B. Phone - any high-resistance small-sized. Capacitor C2 of the PDA type is ceramic, for 8 ... 30p, 5 ... 20p or 4 ... 15p, it is adjusted by turning the screw located in the middle. As a power source, you can use a Krona 9 V battery. Any switch, for example, a toggle switch.
Setting relatively simple. You need to connect the phone, power and antenna - a piece of mounting wire, the longer the better. It is desirable to hang the antenna out the window or hang it on the window frame. Now you need to put on the headphones (they should have a slight hiss) and by rotating the rotor of the capacitor C2 try to catch one station. If this does not work, you need to stretch the turns of the coil a little and repeat.
Good results from such simple receiver not achieve, but it can receive two or three stations in the VHF FM band. Experiment with stretching and compressing the turns of the L1 coil, the length and location of the antenna, and the supply voltage. Instead of headphones, you can connect a 1 ... 3 kOhm resistor and, from the connection point of this resistor and the emitter of the transistor, apply low-frequency voltage to the ULF, then you can listen to the speakers.
| Designation | Type | Denomination | Quantity | Note | Shop | My notepad |
|---|---|---|---|---|---|---|
| VT1 | bipolar transistor | P416B | 1 | To notepad | ||
| C1 | Capacitor | 12 pF | 1 | To notepad | ||
| C2 | variable capacitor | 8-30pF | 1 | To notepad | ||
| C3 | Capacitor | 36 pF | 1 | To notepad | ||
| R1 | Resistor | 330 kOhm | 1 | 0.5W | To notepad | |
| WA1 | Antenna | 1 | To notepad | |||
| IN 1 | Headset | 1 |
Greetings! In this review, I want to talk about a miniature receiver module operating in the VHF (FM) range at a frequency of 64 to 108 MHz. On one of the specialized Internet resources, I came across a picture of this module, I became curious to study it and test it.
I have a special trepidation for radios, I like to collect them since school. There were schemes from the magazine "Radio", there were just designers. Every time I wanted to assemble the receiver better and smaller. The last thing I collected was the design on the K174XA34 chip. Then it seemed very “cool”, when in the mid-90s I first saw a working circuit in a radio store, I was impressed)) However, progress is moving forward, and today you can buy the hero of our review for “three kopecks”. Let's take a closer look at it.
View from above. 
Bottom view. 
For scale next to the coin. 
The module itself is built on the AR1310 chip. I could not find an exact datasheet for it, apparently it was made in China and its exact functional structure is not known. On the Internet, only wiring diagrams come across. A Google search reveals: "This is a highly integrated, single-chip, stereo FM radio. The AR1310 supports frequency range FM 64-108 MHz, the chip includes all the functions of FM radio: low noise amplifier, mixer, oscillator and low drop stabilizer. Requires a minimum of external components. It has good quality audio signal and excellent reception quality. AR1310 does not require control microcontrollers and no additional software except 5 buttons. Operating voltage 2.2 V to 3.6 V. consumption 15 mA, in sleep mode 16 uA ".
Description and specifications AR1310
- FM frequency reception range 64 -108 MHz
- Low power consumption 15 mA, sleep mode 16 uA
- Support for four tuning ranges
- Using an inexpensive 32.768KHz quartz resonator.
- Built-in two-way function automatic search
- Support for electronic volume control
- Support for stereo or mono mode (when closing 4 and 5 pins, the stereo mode is turned off)
- Built-in 32 ohm class AB headphone amplifier
- Does not require control microcontrollers
- Operating voltage 2.2V to 3.6V
- In SOP16 housing
Pinout and overall dimensions of the module. 
Pinout of the AR1310 chip. 
Wiring diagram taken from the Internet. 
So I made a wiring diagram for the module. 
As you can see, the principle is nowhere simpler. You will need: 5 tact buttons, a headphone jack and two 100K resistors. Capacitor C1 can be set to 100 nF, you can set it to 10 microfarads, or you can not set it at all. Capacitances C2 and C3 from 10 to 470 uF. As an antenna - a piece of wire (I took the MGTF 10 cm long, because the transmitting tower is in my neighboring yard). Ideally, you can calculate the length of the wire, for example at 100 MHz, taking a quarter wave or one eighth. For one eighth it will be 37 cm.
I would like to comment on the diagram. AR1310 can work in different ranges (apparently for more quick search stations). This is selected by a combination of pins 14 and 15 of the microcircuit, connecting them to ground or power. In our case, both legs sit on VCC.
Let's start assembling. The first thing I encountered was a non-standard inter-output step of the module. It is 2 mm, and it will not work to put it in a standard breadboard. But it doesn't matter, taking pieces of wire, just soldered them in the form of legs. 
Looks good)) Instead of a breadboard, I decided to use a piece of textolite, assembling the usual "fly". As a result, here is the board. Dimensions can be significantly reduced by using the same LUT and smaller components. But I did not find other details, especially since this test stand, for rolling. 
After applying power, press the power button. The radio receiver immediately earned, without any debugging. I liked the fact that the search for stations works almost instantly (especially if there are a lot of them in the range). The transition from one station to another is about 1 s. The volume level is very high, it is unpleasant to listen to the maximum. After turning off the button (sleep mode), remembers the last station (if you do not completely turn off the power).
Sound quality testing (by ear) was carried out with Creative (32 ohm) “drop” type headphones and Philips “vacuum” type headphones (17.5 ohm). And in those, and in others, I liked the sound quality. No squeakiness, enough low frequencies. A music lover from me is useless, but the sound of the amplifier of this microcircuit was pleasantly pleased. In Phillips, I could not unscrew the maximum volume, the sound pressure level was painful.
I also measured the current consumption in sleep mode 16 μA and in working 16.9 mA (without connecting headphones). 
When connecting a load of 32 ohms, the current was 65.2 mA, with a load of 17.5 ohms - 97.3 mA. 
In conclusion, I will say that this radio receiver module is quite suitable for domestic use. Even a schoolboy can assemble a ready-made radio. Of the "minuses" (rather not even cons, but features), I note the non-standard pin-to-pin pitch of the board and the lack of a display for displaying information.
I measured the current consumption (at a voltage of 3.3 V), as we see, the result is obvious. At a load of 32 ohms - 17.6 mA, at 17.5 ohms - 18.6 mA. This is a completely different matter!!! The current changed slightly depending on the volume level (within 2 - 3 mA). I corrected the diagram in the review. 
This simple FM receiver circuit is quite compact, it can be easily built into a small speaker, a flashlight, old equipment that does not support the FM band, and so on. The circuit diagram is shown in Figure 1. This circuit is built on a specialized TDA7088T microcircuit, which is a superheterodyne with a low frequency. The receiver input circuit consisting of coil L1 and capacitors C2, C3 is tuned to a frequency of 87 ... 108 MHz. By changing the inductance of the coil L1 (increasing or decreasing the distance between the turns), the maximum sensitivity of the receiver is achieved. The search for radio stations is carried out by briefly pressing the SB2 "Start" button. When the end of the range is reached, return to the beginning is carried out by pressing the button SB1 "Reset". Automatic frequency control is carried out by the VD1 varicap, the L2 coil and the C7 capacitor. By increasing the distance between the turns of the coil L2, you can adjust the range, and by increasing the number of turns of the coil by 1.5 times, rebuild it to a frequency of 66 ... 73 MHz. Capacitor C1 serves to protect the receiver, it will not miss the positive component. This is necessary if you will embed the receiver in the equipment and use the body of the device as an antenna. The DA2 chip is a 3V voltage regulator. The 1.2 W output amplifier consists of a DA3 chip. The power supply voltage of the amplifier varies from 4.5 to 18V, so the power supply of the amplifier is turned on before the DA2 stabilizer. Volume control is carried out by resistor R4.
For the manufacture of coils, we need a PEV-2 wire with a thickness of 0.51 mm. and mandrels with a diameter of 4mm and 2.5mm. Coil L1 is 5.5 turns on a 4mm mandrel. And the L2 coil is 5.5 turns on a 2.5mm mandrel.
The current consumption of the receiver with this amplifier does not exceed 25mA. Therefore, a dissipative heat sink for the DA2 voltage regulator is not required. The antenna is connected to connector XS1.
The details of this receiver are mounted on two boards made of one-sided fiberglass. On PCB #1 the radio itself is presented, and on PCB №2 amplifier and stabilizer. This is done so that this radio can be built into equipment with a ready-made amplifier.
That's all, if you have any suggestions or comments write to the site administrator.
Today we will analyze the TOP-3 working circuits of HF, VHF, FM tube receivers. First of all, let's look at how to assemble the simplest tube HF receiver. The second project is a VHF FM receiver in retro style. According to the third scheme, we will assemble a low-voltage tube super-regenerative FM receiver without an output transformer.
First, consider an interesting HF receiver circuit. This radio receiver is very sensitive and selective enough to receive shortwave frequencies around the world. One half of the 6AN8 tube serves as an RF amplifier and the other half as a regenerative receiver. The receiver is designed to work with headphones or as a tuner followed by a separate bass amplifier.
For the case, take thick aluminum. The scales are printed on a sheet of thick glossy paper and then glued to the front panel. The winding data of the coils are indicated in the diagram, there is also the diameter of the frame. Wire thickness - 0.3–0.5 mm. Winding coil to coil.
Tune in to the desired station with variable capacitor C5 approx. Now capacitor C6 - for fine tuning to the station. If your receiver does not accept normally, then either change the values of resistors R5 and R7, which form additional voltage through the potentiometer R6 at the 7th output of the lamp, or simply swap the connection of contacts 3 and 4 on the coil feedback L2. The minimum length of the antenna will be about 3 meters. With a conventional telescopic one, it will be rather weak to take.
Superregenerators are a very interesting type of radio receivers, which are distinguished by their simplicity of circuits and good characteristics comparable to simple superheterodynes. Subjects were extremely popular in the middle of the last century (especially in portable electronics) and they are intended primarily for receiving stations with amplitude modulation in the VHF band, but can also receive stations with frequency modulation (i.e., for receiving those same conventional FM stations).
main element of this type receivers is a super-regenerative detector, which is both a frequency detector and an RF amplifier. This effect is achieved through the use of adjustable positive feedback. It makes no sense to describe the theory of the process in detail, since “everything has been written before us” and can be mastered without problems using this link.
This scheme was taken as a basis:
Now let's go through the elements of the circuit in more detail and start with the 6n23p lamp (double triode):
Now let's go through the scheme from left to right. It is best to wind the inductors L1 and L2 on a common round base (mandrel), a medical syringe with a diameter of 15 mm is ideal for this, and it is desirable to wind L1 over a cardboard tube that moves with little effort along the syringe body, which ensures adjustment of the connection between the coils. As an antenna, you can solder a piece of wire to the extreme output of L1, or solder the antenna jack and use something more serious.
It is advisable to wind L1 and L2 with a thick wire to increase the quality factor, for example, with a wire of 1 mm or more in 2 mm increments (special accuracy is not needed here, so you don’t have to bother with each turn). For L1, you need to wind 2 turns, and for L2 - 4-5 turns.
Next come capacitors C1 and C2, which are a two-section variable capacitor (KPI) with an air dielectric, it is perfect solution for such circuits, KPI with a solid dielectric is undesirable. Probably, KPI is the rarest element of this circuit, but it is quite easy to find it in any old radio equipment or at flea markets, although it can also be seen with two ordinary capacitors (necessarily ceramic), but then you will have to adjust with an impromptu variometer (a device for smoothly changing inductance). KPI example:
This is followed by a quenching chain, made on the resistor R1 (2.2 MΩ) and the capacitor C3 (10 pF). Their values can be changed within small limits.
Coil L3 acts as an anode choke, i.e. high frequency is not allowed to pass further. Any inductor (but not on an iron magnetic circuit) with an inductance of 100–200 μH will do, but it is easier to wind 100–200 turns of a thin copper enameled wire around the body of a worn-out powerful resistor.
Capacitor C4 serves to separate the DC component at the output of the receiver. Headphones or an amplifier can be connected directly to it. Its capacity can vary within fairly large limits. It is desirable that C4 be film or paper, but it will also work with ceramic.
Resistor R3 is a conventional 33 kΩ potentiometer, which serves to regulate the anode voltage, which allows you to change the lamp mode. This is necessary for a more precise adjustment of the mode for a specific radio station. You can replace it with a fixed resistor, but this is undesirable.
This completes the elements. As you can see the circuit is very simple.
And now a little about the power supply and installation of the receiver.
Anode power supply can be safely used from 10V to 30V (more is possible, but it is already a little dangerous to connect low-resistance equipment there). The current there is quite small and a PSU of any power with the required voltage is suitable for power supply, but it is desirable that it be stabilized and have a minimum of noise.
And another prerequisite is the power supply of the lamp incandescence (in the picture with the pinout it is indicated as heaters), since without it it will not work. Here, more currents are needed (300–400 mA), but the voltage is only 6.3V. Both AC 50 Hz and DC voltage are suitable, and it can be from 5 to 7V, but it is better to use the canonical 6.3V. Personally, I have not tried using 5V on the glow, but most likely everything will work fine. Heat is supplied to legs 4 and 5.
Now about the installation. Ideally, all circuit elements are located in a metal case with ground connected to it at one point, but it will work without a case at all. Since the circuit operates in the VHF band, all connections in the high-frequency part of the circuit should be as short as possible to ensure greater stability and quality of the device. Here is an example of the first prototype:
Now for the setup.
After you are 100% sure that the installation was correct, you applied voltage and nothing exploded or caught fire - this means that the circuit most likely works if the correct element values \u200b\u200bare used. And you will most likely hear noises in the headphones. If in all positions of the KPI you do not hear the stations, and you are sure that you receive broadcast stations on other devices, then try changing the number of turns of the L2 coil, this will rebuild the resonance frequency of the circuit and possibly fall into the desired range. And try turning the knob of the variable resistor - that might help too. If nothing helps at all, then you can experiment with the antenna. This completes the setup.
Video about assembling a tube receiver:
Pure tube version (at the breadboard level):
Option with the addition of ULF to the IC (already with the chassis):
