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Hf Broadband Antenna Preamp Circuit
The HF/SW receiver preamplifier is comprised of a broadband toroidal transformer (LI-a and Ll-b), LC network (comprised of a 1600-kHz, high- pass filter-and a 32-MHz, low-pass filter), L2 and L3 (26 turns of #26 enameled wire wound on an Amidon Associates T-50-2, red, toroidal core), a pair of resistive attenuators (ATTN1 and ATTN2), and a...
Automatic Tr Switch Circuit
A pair of diodes and a quarter-wave transmission line are used as an automatic TR switch. D1 and D2 conduct during transmit periods, short- circuiting the scanner input. In this mode,-the K-wave line appears as an open circuit.
915-MHz antenna monopole
The Tab antenna is a folded monopole that you miniaturize by forming it into an inverted L with a downward bend at the end (Figure 1). You can solder it perpendicular to a pc board or build it as part of a pc board and place it at a corner. The folded section transforms the 12.5Ω radiation resistance to 50Ω and provides second-harmonic...
Energy-sucking Radio Antennas
Here's something that has always bugged me: light waves are about 5000 Angstroms in wavelength, while atoms are more like 1 Angstrom across. Atoms are thousands of times smaller than light waves, yet atoms obviously interact very strongly with light. How can they do this? Perhaps they get around the problem by employing Quantum Mechanics...
Tin Can Waveguide WiFi Antenna
Got no dough for a commercial WiFi antenna? Looking for an inexpensive way to increase the range of your wireless network? A tin can waveguide antenna, or Cantenna, may be just the ticket. This design can be built for under $5 U.S. and reuses a food, juice, or other tin can.
Shorty Forty Antenna
City dwellers and other flat dwellers know the practical difficulties they encounter when they try to put up an antenna for 40 meters. Finding space enough to accommodate 67 feet of wire is a real problem for them and most of them have to be satisfied by the inverted V. Whatever the book say, in practice the inverted V does not come up to the...
Ground pole & 2-Half-Wave Dipole Antenna
This Antenna is most widely used all over the world. For example, when you see a police car it has a transmitter with Ground Pole Antenna The body of car serves as ground). It accepts load from 50 ohm source and has larger power output than Half-Wave Dipole Antenna.
Antennas for HAM transmitters
Antenna is the means by which a wireless operator puts his signal into the space and also through which he picks up the signals of the stations with which he wants to communicate. Hence after having a good Receiver and a Transmitter (or Transceiver), the next important item one should have to set up a ham radio station is a good antenna.
J-Pole Antenna 89Mhz
This antenna is made from 1/2" copper tubing and it is soldered together with plumbing tees, elbows, and nipples..
VHF 5/8wave vertical antennas
At VHF, both the 1/4-wavelength monopole and the 5/8-wavelength monopole antennas are widely used. The VHF 5/8-wavelength (144 Mhz) vertical monopole has long held the reputation of providing about a 3-dB gain advantage over the 1/4-wavelength vertical monopole. The foundation of that reputation rests upon theoretical calculations that show the...
J-POLE for VHF/UHF
SWR can be adjusted by adjusting the connection point L3 figher or lower.
VHF/UHF Dualband vertical
Use for this antenna tube of 10mm diameter. Or you can use a brass rod of about 7mm diameter. The top one is a strong copper (brass) wire of 5 to 7 mm diameter soldered directly to the coil and mounted to the PVC isolator to give a strong construction.
Quarter wave vertical antenna
To calculate the length of the elements of other bands use the above formula. Example 6 meter band (50Mhz): (75/50)*0.96=1.44 meters
Full wave omnidirectional
This is a Full wave omni directional vertical ground plane antenna for 2-meters plan with 250 watts max power.
VHF Portable "rubber duck" antenna
You can make your own 2-meter "rubber duckies" that will likely perform much better than many commercial units. I compared my design with two other "rubber duckies" of the TH215 and ICT7 which outperformed them both. With the "duckie" of the ICT7e as much as 10dB. It does not has a gain compared to a 1/4wave antenna ofcourse, but compared to...
UHF 3-element portable
This design notes shows a UHF 3-element portable antenna with gamma-match.
VHF/UHF Wideband Portable Dipole
I wanted a robust, portable, compact antenna usable for horizontal and vertical polarisation to take along with my FT-817 when I go on vacation, camping etc. I also wanted the dipole to cover the VHF and UHF bands and if possible with some gain! As everybody knows a dipole has about 3dB gain over a quartre wave antenna, is why my preference went...
Vipor mutant portable HF/VHF/UHF
Most of us don`t have the luxury of building a 1/4, 1/2 or even a 5/8 wavelength vertical antenna for HF. We have to settle for something a little shorter. (A lot shorter, in the case of people following the FCC`s Part 15 rules, which limit them to 3 meters in size.) Shorter vertical antennas can give acceptable (but not spectacular) performance.
Q-Multiplying Loop Antenna
This circuit is designed to be used in conjunction with the standard 4 foot square loop used in MW for long distance reception.
RF Dummy load
The load described here is capable of handling up to 10 watts of RF power for a couple of minutes, and is designed for the widely used 50 ohms impedance. It consists of ten parallel connected 560 ohms 1 watt resistors, R1 through R10, a voltage divider, R11-R12, and a rectifier D1-C1. Apart from loading the transmitter output with a minimum of...
Dipole antenna for two metres
Described here is a simple omnidirectional, vertically-polarised dipole for two metres. Made from coaxial cable, it can be rolled up and stored in a small container. It may be used as is indoors, or waterproofed for use outside. No extravagant gain claims are made; this dipole has no more gain than any other. However, it should be significantly...
VHF Antenna Amplifier Circuit Using BFT66 Transistor
Here`s a design circuit for very simple antenna amplifier electronic circuit project can be designed using this circuit diagram. This antenna amplifier electronic circuit can be used for a frequency range between 1 and 300MHz. This circuit antenna amplifier can be used for high frequency and VHF band (for radio and TV) and will provide a 22 dB gai
high gain antenna 43dB amplifier circuit
A very simple and useful antenna amplifier can be constructed using this circuit diagram. This antenna amplifier is very useful for 35kHz-150Mhz frequency band. This antenna amplifier circuit is based on transistors and has a low 3 dB non-linearity and a high gain of 43 dB. The input and output impedance for this rf amplifier is 75 ohms. The L
VHF UHF HF active antenna electronic circuit project with explanation
A very simple and efficiency active antenna electronic project can be designed using this electronic schematic circuit that is based on transistors. This active antenna electronic project is useful for a wide range of RF frequencies covering three RF bands HF, VHF and UHF. This simple active antenna is designed to amplify signals from 3 to 3000
Sequential pulsing logic
Antenna Circuit Analysis
Power control circuit
Meter circuit schematic diagram
Antenna Positioning and Drive Circuits
Modulator Schematic Diagram
Antenna Tower Electrical Circuit Schematic Wiring Diagram
Active Antenna Circuits
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Yagi Uda Antennas
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial