10 years ago
Showing posts with label Transmitter. Show all posts
Showing posts with label Transmitter. Show all posts
VHF Booster Schematic
Wednesday, October 13, 2010
The quality of this VHF booster seems not better than the one sold in electronic stores. Look at the picture! Only a few parts needed to finish it. Anyway, the result was more than I expected. Most of VHF local and foreign TV (Singapore and Malaysia) can be enjoyed clearly. I lived in north part of Indonesia, in a three angle border between Indonesia, Singapore and Malaysia. That's why TV channels from those countries can be captured easily.
The basic part of this schematic is TR1 (C2570), specially designed for amplifying VHF and UHF signal. No coil needed for this project …
You may omit S2, as per PCB diagram, I have deleted S2 to connect the antenna and TV set permanently through the booster.
The basic part of this schematic is TR1 (C2570), specially designed for amplifying VHF and UHF signal. No coil needed for this project …
You may omit S2, as per PCB diagram, I have deleted S2 to connect the antenna and TV set permanently through the booster.
3V FM Transmitter
Tuesday, October 12, 2010
Hi… I’m back!
I have been ignored this blog for long periods since I was busy with my other activities. This is my last bug project. Works well on 88-108 MHz frequency. It already published on my paid Blog, http://myelectronickit.com. Unfortunately the Blog is already suspended since the hosting provider ran away. All data that I have been created and published for almost one year in the Blog were lost.
Okay … let’s focus on this project. All information regarding this small transmitter is clearly stated in the picture, including how to build the coil. Please let me know if you have difficulties.
Simplest Sonar
Wednesday, January 13, 2010
SONAR stands for Sound Navigation Ranging, and is a technique for determining the distance and direction of objects by acoustic means. Although SONAR is usually associated with navigation ranging under water, it may also be used to good effect in air – for instance, to detect boats in a fog.
SONAR may be divided into three categories.
1. Active SONAR
Projects a sound wave and waits for the echo, which these days can be analysed with great sophistication.
2. Passive SONAR
Projects no sound, but analyses incoming sound, e.g. to identify a passing submarine; and a third category of
3. SONAR transmits and receives messages across an “acoustic path”.
The SONAR described here is an active system, with the most basic functionality – it simply reports the existence of an object within a 1 metre (1 yard) range. In fact, with just five components, this has to be the simplest SONAR in the world!
Middle Range FM Transimtter
Thursday, November 19, 2009
The transmitter circuit described here consist of two parts. Its called as the Oscilator stage and an extra RF power amplifier stage to raise the power output to 200-250 milliwatts.
The circuit built around transistor T1 (BF494) is a basic low-power variable-frequency VHF oscillator. A varicap diode circuit is included to change the frequency of the transmitter and to provide frequency modulation by audio signals. The output of the oscillator is about 50 milliwatts. Transistor T2 (2N3866) forms a VHF-class A power amplifier. It boosts the oscillator signals’ power four to five times. Thus, 200-250 milliwatts of power is generated at the collector of transistor T2.
VR1 is used to vary the fundamental frequency whereas potentiometer VR2 is used as power control. For hum-free operation, operate the transmitter on a 12V rechargeable battery pack of 10 x 1.2-volt Ni-Cd cells. Transistor T2 must be mounted on a heat sink.
Inductors Data
L1 - 4 turns of 20 SWG wire close wound over 8mm diameter plastic former.
L2 - 2 turns of 24 SWG wire near top end of L1.
(Note: No core (i.e. air core) is used for the above coils)
L3 - 7 turns of 24 SWG wire close wound with 4mm diameter air core.
L4 - 7 turns of 24 SWG wire-wound on a ferrite bead (as choke).
Notes
* Do not switch on the transmitter without a matching antenna. It is a must, or your transmitter (transistor) will get burn.
* Adjust both trimmers (VC1 and VC2) for maximum transmission power. Adjust potentiometer VR1 to set the fundamental frequency near 100 MHz.
Video Transmitter
Friday, October 23, 2009
Works between 76 and 108 MHz frequency. You may replace 2SC2000 with : 2SD734, C930 or the equivalent type.
Inductor
L1 = 5 mm diameter of air core
Size = 0.8 mm enameled copper wire
The turns are depending upon the frequency you want,
5 - 4 turns: 40 - 90MHz
3 - 2 turns: 100 - 180MHz
FM Transmitter #2
Thursday, October 22, 2009
This series of transmitter consists of three parts ... oscillator, buffer #1, and buffer #2. Quality of the oscillator is quite satisfactory, stable and produces a strong signal.
The first part to assemble is the oscillator. Once finished, turn on the FM radio on an empty wave. Turn on the transmitter / oscillator. Turn the ferrite core (L1) to the left / right until the radio hissing sound gone. This means that the oscillator works well. However, the transmission distance is still very limited / less than 2 meters.
Next part to assemble is the buffer 1. After finished assembling the Buffer section 1, try to test the transmitter again. The transmission distance will increase a few meters, but still not stable. Do the same thing to buffer 2.
With power output of more than 0.25-Watt, transmitter distance can be more than 100 meters, but needed a comprehensive antenna. For better quality, Q2 can be replaced with type C2053 but cost a bit more expensive. C8 and C11 can also be replaced with the size 33pf.
Using a stable power supply is a must for this transmitter to work properly. >>
Inductors Data
L1 = 0.5 mm diameter of ferrite core
P = 1 turns
S = 3 turns
S = 3 turns
Size = 0.3 mm enameled copper wire
L2 + L3 = 0.8 diameter of air core
3 turns
Size = 0.6 mm enameled copper wire
This FM transmitter used to enjoy music from PC or TV. I covered it with DV cassette case... and added a volume adjuster (VR). Sorry about the picture quality.
3 turns
Size = 0.6 mm enameled copper wire
This FM transmitter used to enjoy music from PC or TV. I covered it with DV cassette case... and added a volume adjuster (VR). Sorry about the picture quality.
SWG and AWG to mm CONVERSION TABLE
Sunday, October 18, 2009SWG : Standard Wire Gauge
AWG : American Wire Gauge
Sometimes, you'll need to make your own coil when you build a radio transmitter or receiver. But you will find all the wires diameters in SWG or AWG unit. For converting to mm, you can use two tables below:
AWG : American Wire Gauge
Sometimes, you'll need to make your own coil when you build a radio transmitter or receiver. But you will find all the wires diameters in SWG or AWG unit. For converting to mm, you can use two tables below:
3 VOLT FM TRANSMITTER
Saturday, October 17, 2009This is the simplest FM transmitter using two BC547 transistors.
Components may be added to the PCB in any order. Note that the electret microphone should be inserted with the pin connected to the metal case connected to the negative rail (that is, to the ground or zero voltage side of the circuit).
The coil should be about 3mm in diameter and 5 turns. The wire is tinned copper wire, 0.61 mm in diameter. After the coil soldered into place spread the coils apart about 0.5 to 1mm so that they are not touching. (The spacing in not critical since tuning of the TX will be done by the trim capacitor.
It is quite possible, but not as convenient, to use a fixed value capacitor in place of the trim capacitor - say 47pF - and to vary the TX frequency by simply adjusting the spacing of the coils. That is by varying L of the LC circuit rather than C.) Adding and removing the batteries acts as a switch.Connect a half or quarter wavelength antenna (length of wire) to the aerial point. At an FM frequency of 100 MHz these lengths are 150 cm and 75 cm respectively.
Good luck!!
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