Dilshan Jayakody published a new build, a VHF Aircraft radio communications receiver:
This is simple radio receiver project which is capable to receive aviation radio voice signals which are transmit between 118MHz to 138MHz in AM (A3E). We got initial idea of this project by reading Sverre Holm’s (LA3ZA) article about “cheap VHF receiver project”. Like LA3ZA’s original article this project is also based on Samsung’s KA22429 FM radio receiver IC.
KA22429 is low voltage FM radio receiver system developed by Samsung for portable radio receivers and as described by Holm’s it can push into VHF region by changing few values in its original circuit. In this project we redesign the schematic and PCB with some of those changes and now it can directly tune into aviation band with minimum number of adjustments.
VHF Aircraft radio communications receiver - [Link]
Lightning detector that flashes when lightning strikes nearby.
This circuit picks up and amplifies signals in the 300 kHz range, where lightning makes a lot of noise that can be picked up with a radio. The antenna and receiver are tuned to 300 kHz, with the receiver’s output connected to an amplifier that drives the lamp flashing circuit, alerting you to lightning in the area.
Use the potentiometer to reduce the sensitivity to noise and still be able to detect lightning strikes. In addition to lightning, this circuit will also respond to noise from motors inside appliances like refrigerators, washers, and air-conditioners. Another easy way to affect the sensitivity is to take off the antenna, or lengthen it depending on the conditions. To get some confirmation while tuning the detector, you can tune an AM radio to the bottom the of the dial as well.
You can use this circuit to track weather, and be prepared for it. The circuit is small enough and can be placed in a project box or waterproof container to use, on a boat for instance. The lamp can be replaced or even used alongside a buzzer in this circuit to give an audible alert as well, so that constant monitoring of the circuit is not necessary.
Simple Lightning Detector - [Link]
A small, simple AM receiver project. This AM receiver can pick up medium wave stations in your area
This circuit can use general purpose transistors, and in this example there are 3 BC109C transistors. In this schematic and BOM there is a 200uH inductor and a trimmer 150-500pF capacitor, though these parts can be salvaged from an old AM radio, to preserve the directional nature of a tuning coil, and an adjustment knob (plate capacitor) that work well for radio reception.
The 120k resistor is for regenerative feedback between the Q2 NPN transistor and the input to the tank circuit. The value of this resistor is important to the performance of the entire circuit. In fact, it may be better to replace the fixed value with a variable resistor paired with a fixed resistor to adjust the oscillation and sensitivity of the circuit. All the connections in this circuit should be short to minimize interference.
Performance of the circuit will vary depending on stray capacitance in your layout, the inductor winding/core/length, etc. Changing values of some of the capacitors, or adding them, as well as a potentiometer in the feedback loop can help with the performance of the receiver. With such a small circuit that is affected so much by its construction and its environment, a lot of hand tuning and experimentation will be fun, instructive, and possibly necessary to make it work best.
Simple AM Receiver Project - [Link]
With DVR becoming increasingly common over the last few years, DirecTV has sought to distinguish its offerings on that front with multiple levels of service. At the top of the DirecTV DVR receiver options, the Genie offers a huge array of features on a powerful piece of hardware. You can get the newest Genie by signing up for DirecTV using www.SaveonTVDirect.com. For the average user, this means a better viewing experience; for the advanced user, this means the opportunity for interesting hacks; for the enterprising salvager, this means useful parts to collect from an unused or broken unit.
So let’s talk about all the uses you can get out of a Genie, whatever your experience level or goals. Read the rest of this entry »
VHF FM Aircraft receiver:
VHF FM Aircraft Receiver is a superregenative receiver developed for listening to FM transmitters but also tunes the aircraft band and the top portion of the FM broadcast band. Receives both AM and FM (107mHz to 135 MHz). You can use this receiver with the any FM transmitter. The receiver is amazingly simple using only one transistor for the receiver section and one IC for the audio section. This circuit is a self-quenching regenerative RF receiver also known as a superregenerative receiver.
VHF FM Aircraft receiver - [Link]
This project goes through the process of designing and building a simple RF transmitter and RF receiver pair that operate at 27 MHz. Only basic parts like 555 timers and 2N2222 transistors are used to make the modules, so it’s generic but fun.
Old wish to make digitally controlled FM tuner come true when I found on Ebay cheap module with TEA5767 (Low-power FM stereo radio for handheld applications).
This module size is only 11.2mm x 11mm. TEA 5767 supports I2C.
For antenna i have used just 75 cm long wire, because that is 1/4 of wavelength at 100 MHz. TEA5767 doesn’t have audio amplifier, sound output level is very low, headphone can not be connected directly. During testing i had connected audio output to PC audio system.
Arduino FM receiver with TEA5767 - [Link]
Andrew built a DIY GPS receiver with an accuracy of ~25m – [via]
A homemade GPS receiver built from the ground up using discrete components and featuring a limiting IF, followed by 1-bit ADC ahead of DSP signal processing in a Xilinx Spartan 3 FPGA. Fast FFT-based search and navigational solutions are computed by “C” code on a Windows PC
Homemade GPS receiver - [Link]
SiRFstarIII based GPS RADIONOVA provides complete GPS system solution for embedded GPS applications
Antenova Ltd, an integrated antenna and RF solutions company, announced a special sub-$3 price offering of its GPS RADIONOVA SS3 Receiver Module – a complete GPS receiver including SiRFstarIII GPS IC and all front end RF components in a very small low profile single package module. The SS3 GPS Receiver Module is a complete drop in solution for a wide range of embedded applications including ‘GPS mouse’ (USB dongles), personal trackers, automatic vehicle locators (AVLs), vehicle black boxes, data loggers, media tablets and portable media players (PMPs). [via]
Complete GPS receiver module for under $3 - [Link]
Much as humans and other animals see via waves of visible light that bounce off objects and then strike our eyes’ retinas, radar “sees” by sending out radio waves that bounce off targets and return to the radar’s receivers. But just as light can’t pass through solid objects in quantities large enough for the eye to detect, it’s hard to build radar that can penetrate walls well enough to show what’s happening behind. Now, MIT Lincoln Lab researchers have built a system that can see through walls from some distance away, giving an instantaneous picture of the activity on the other side.
The researchers’ device is an unassuming array of antennas arranged into two rows — eight receiving elements on top, 13 transmitting ones below — and some computing equipment, all mounted onto a movable cart. But it has powerful implications for military operations, especially “urban combat situations,” says Gregory Charvat, technical staff at Lincoln Lab and the leader of the project. [via]
Radar can see through walls - [Link]