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Category: RF Circuits / RF Receivers This circuit is also crossed to: Varius Circuits Views: 5752 Rank: 0 The direct conversion receiver described consists of only a bandpass filter, mixer IC, VFO and audio filter. With only 22 parts, this simple circuit should take a few hours at the weekend to construct. For extra simplicity, eliminate L1 & C1 and connect C2 to the slider of P1. The oscillator section of the NE612 is configured as either a series-tuned Colpitts- or Clapp oscillator. Depending on the parts the receive range is from 10050 kHz to 10250 kHz. Due to component tolerances the number of turns and/or the capacity of L3 and C7 are adjusted to tune the required portion of the band. The mixer stage is followed by a selective audio amplifier. Balanced DC voltage levels at the mixer outputs and amplifier inputs allow a component saving direct coupling. After suppressing the unwanted RF products by C9 and C10 the remaining AF is passed through to the non-inverting inputs of TL072 dual op amp. A series resonant circuit, built out of Dr1 and C1, aids some AF selectivity. The AF stage has a gain of 46 dB at its 660 Hz resonant frequency. Audio volume is controlled by the attenuator P1 at the antenna terminal. The TL072 outputs aren't of low impedance. So, when connecting 60 ohm headphones one should arrange a 470 ohm resistor in series. The receiver operates in a voltage range from Ub=8 ... 15 V. The AF stage is supplied directly by Ub and the mixer gets a +6 V constant voltage from IC2. The receivers current consumption is approx. 6 mA with no input signal. You can save 1 ... 2 mA when using a 6 V regulator type with lower quiescent current. Alignment For the receiver alignment use of an existing receiver is recommended. Check the VFO frequency first. Receiver tuning should be possible between 10050 kHz (C4 max.) and 10250 kHz (C4 min.) by means of the variable capacitor. For this, listen to the VFO signal on the other receiver. Parts list Parts No. Value P1 1 kOhm potentiometer R1, R2 10 kOhm C1, 3 5 .. 90 pF trimmer capacitor C2 3,9 pF C4 2 x 20 pF VHFbroadcast variable capacitor C5 100 pF C6 220 pF C7 150 pF C8 0,1 u F C9, 10 47 nF C11 2,2 u F C12 100 u F, 25 V L1, 2 T50-2, 30 turns prim. / 3 turns sec. L3 T50-2, 30 turns Dr1 33 mH IC2 NE612 DIP IC2 78L06 IC3 TL072 DIP e.g. KH Headphone Ri > 60 Ohm visit page.  The mixer stage is followed by a selective audio amplifier. Balanced DC voltage levels at the mixer outputs and amplifier inputs allow a component saving direct coupling. After suppressing the unwanted RF products by C9 and C10 the remaining AF is passed through to the non-inverting inputs of TL072 dual op amp. A series resonant circuit, built out of Dr1 and C1, aids some AF selectivity. The AF stage has a gain of 46 dB at its 660 Hz resonant frequency. Audio volume is controlled by the attenuator P1 at the antenna terminal. The TL072 outputs aren't of low impedance. So, when connecting 60 ohm headphones one should arrange a 470 ohm resistor in series. The receiver operates in a voltage range from Ub=8 ... 15 V. The AF stage is supplied directly by Ub and the mixer gets a +6 V constant voltage from IC2. The receivers current consumption is approx. 6 mA with no input signal. You can save 1 ... 2 mA when using a 6 V regulator type with lower quiescent current. Alignment For the receiver alignment use of an existing receiver is recommended. Check the VFO frequency first. Receiver tuning should be possible between 10050 kHz (C4 max.) and 10250 kHz (C4 min.) by means of the variable capacitor. For this, listen to the VFO signal on the other receiver. Parts list Parts No. Value P1 1 kOhm potentiometer R1, R2 10 kOhm C1, 3 5 .. 90 pF trimmer capacitor C2 3,9 pF C4 2 x 20 pF VHFbroadcast variable capacitor C5 100 pF C6 220 pF C7 150 pF C8 0,1 u F C9, 10 47 nF C11 2,2 u F C12 100 u F, 25 V L1, 2 T50-2, 30 turns prim. / 3 turns sec. L3 T50-2, 30 turns Dr1 33 mH IC2 NE612 DIP IC2 78L06 IC3 TL072 DIP e.g. KH Headphone Ri > 60 Ohm http://www.qrp4u.de/docs/en/direkt_rx/index.htm
Related circuits Direct Crystal radio receiver examples No description available. Super-Simple Shortwave Receiver Circuit Integrated circuit Ul (an NE602 double-balanced mixer) is a combination oscillator and frequency mixer. Signals from the antenna input (at Jl) are fed through dc-blocking capacitor C1 to the RF-gain control, Rl, and fed to the input of Ul at pins 1 and 2. The local-oscillator frequency, which... Using an NE602 heterodyne detector and Ul as an RF amplifier, this receiver tunes the middle portion of the l Mini FM Receiver using TDA7088 The electronic diagram of the monophonic FM receiver made with TDA7088T is shown on Pic.4.12. If built with SMD components it can be placed in a matchbox, altogether with two button-type batteries. The operating principle of this device is given in the previous chapter. The only thing new is a... This is a simple RF receiver mainly for low-distance digital radio receiver application. The analog output of this circuit should be connected to a schmitt-trigger signal conditioning circuit with a proper value capacitor (from collector of T3). L1 for 27Mhz is about 10 turns, 6 mm diameter coil... This circuit provides interferenced rejection for the CW operator. The 567 phase-locked loop is configured to respond to tones from 500 to 1100 Hz. The Schmitt trigger reduces the weighting effect caused by the output of the PLL remaining low after removal of the audio signal. Ten to 15... Here is a nice little receiver for narrow-band FM reception. It can also be used to receive FSK, RTTY and PACKET signals from the HF bands. Basic receiver sensitivity is in the region of 1uV PD and the receiver can be tuned to almost any frequency from 100KHz up to probably 120MHz. It is a bit... A regenerative radio works by feeding back a small amount of amplified output of the detector back into the input. Thus it achieves sensitivity far beyond what only a detector could alone. This simple regen radio uses a single tube as it's detector and amplifier; the "Audion". It's a great first...
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Another aviation-band Super-regenerative radio receiver Circuit from a Japanese book. ... Another aviation-band Super-regenerative radio receiver. Circuit from a Japanese book. Attached Images ...
The problem is how to receive the signal with a receiver that is low power, and can run for weeks from a single battery. I decided to try a Superregenerative VHF FM band receiver. The schematic I used is found at the end of ...
This receiver is designed to cover only about 2 KHz in the 80 meter band. The frequency is determined by the input transformer resonant circuit (see Figure 2) and the VFO tuned circuit (see Figure 4). T1 is an IF transformer ...
40 m Band Direct Conversion Receiver. 40 m Band Direct Conversion Receiver ... Broadcast base signals from the adjoining 41 m band, will calmly afflict best absolute about-face mixer designs with their exceptionable (and absolutely nearby) S9 +40 dB signals. My band-aid incorporates a diode-ring ...
Communication in F.M. band is easy..circuit diagram with description of Power Full F.M. receiver using single IC receive 88 MHz to 108 MHz frequency in F.M. band,
Receivers. Reconfigurable Multi-Band OFDM UWB Receivers. RF System Design of Transceivers for Wireless Communications ( Re. RF Circuit Design: Theory & Applications. His thesis was "Advanced Concept and Design ...
Good FM Receiver Circuit for FM Transmitters outside the 88-108 Band
Radio Electronics: Frequency Modulation Basic Principles pt1-2 1964 US Army T...
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