5 Watt FM Amplifier
 
5 Watt FM Amplifier


 

5 Watt FM Amplifier

 


This design is a 2 stage amplifier that has about 17db of gain, suitable for an input of 50 to 100 MW. Its basically a Veronica 5 watt vco transmitter, without the vco. The transistors are a 2N4427 and a MRF237. Output power is 2.5 to 5 watts, depending on input drive and dc voltage. At 13.7 vdc with 50 MW of drive, the output was 2.5 watts. The maximum dc voltage recommended is about 15-16 volts.


5 Watt FM Amplifier

The unit is constructed with copper clad board, a large piece is used as the construction surface and is mounted into a case. Other board material is cut into small pads, then glued to the construction surface for part connections. A heatsink is needed for the both transistors, a small "top hat" style will work for TR1 but TR2 requires a larger heatsink thats attached to the case. This is made from aluminum L stock, a 3/8" hole and a slot is made for TR2 to fit snuggly in. Up to 7-8 watts output is possible with this amp, but for continious duty only 5 watts maximum output is recommended. A fan is required and it is mouted on the case lid, with holes drilled for ventilation. The chokes H1, H2 and H3 are 5 turns of 30 awg wire on a ferite bead and choke H4 is a 330 ohm 1/2 watt resistor with 14 turns of 30 awg with a ferite bead on each end. Ferite beads need to be of type 43 material. The coils L1, L2 and L3 are made of 18 awg tinned wire. A 1.5 amp 3ag fuse is part of the dc power cord assembly. I used BNC coax connectors for input and output, however SO-239 or F type connectors would be fine too.

Tune up and use: In order to make the amplifier operate properly, it needs to be tuned. To start, set all the trimmer capacitors to middle position, connect the rf out to a wattmeter/dummy antenna, apply power and drive from the exciter then tune for maximum output. Limit your drive to 100 MW maximum. If you can measure the amplifier transistor's current, then adjust for minimum current at maximum rf out. This unit has no swr protection and requires a 50 ohm antenna, do not operate the amplifier without a proper load.


5 Watt FM Amplifier





Accurate LC Meter Capacitance Inductance Meter with 16F628 and LCD
Volt Ampere Meter with 16F876 Microcontroller and LCD display
 
Accurate LC Meter

Build your own Accurate LC Meter (Capacitance Inductance Meter) and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils and inductors. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging as well as reset switch and produces very accurate and stable readings.
PIC Volt Ampere Meter

Volt Ampere Meter measures voltage of 0-70V or 0-500V with 100mV resolution and current consumption 0-10A or more with 10mA resolution. The meter is a perfect addition to any power supply, battery chargers and other electronic projects where voltage and current must be monitored. The meter uses PIC16F876A microcontroller with 16x2 backlighted LCD.

50MHz 60MHz Frequency Meter / Counter with 16F628 & LCD
1Hz - 2MHz XR2206 Function Generator
60MHz Frequency Meter / Counter

Frequency Meter / Counter measures frequency from 10Hz to 60MHz with 10Hz resolution. It is a very useful bench test equipment for testing and finding out the frequency of various devices with unknown frequency such as oscillators, radio receivers, transmitters, function generators, crystals, etc.
1Hz - 2MHz XR2206 Function Generator

1Hz - 2MHz XR2206 Function Generator produces high quality sine, square and triangle waveforms of high-stability and accuracy. The output waveforms can be both amplitude and frequency modulated. Output of 1Hz - 2MHz XR2206 Function Generator can be connected directly to 60MHz Counter for setting precise frequency output.

BA1404 HI-FI Stereo FM Transmitter
USB IO Board PIC18F2455 / PIC18F2550
BA1404 HI-FI Stereo FM Transmitter

Be "On Air" with your own radio station! BA1404 HI-FI Stereo FM Transmitter broadcasts high quality stereo signal in 88MHz - 108MHz FM band. It can be connected to any type of stereo audio source such as iPod, Computer, Laptop, CD Player, Walkman, Television, Satellite Receiver, Tape Deck or other stereo system to transmit stereo sound with excellent clarity throughout your home, office, yard or camp ground.
USB IO Board

USB IO Board is a tiny spectacular little development board / parallel port replacement featuring PIC18F2455/PIC18F2550 microcontroller. USB IO Board is compatible with Windows / Mac OSX / Linux computers. When attached to Windows IO board will show up as RS232 COM port. You can control 16 individual microcontroller I/O pins by sending simple serial commands. USB IO Board is self-powered by USB port and can provide up to 500mA for electronic projects. USB IO Board is breadboard compatible.

RF Remote Control 433MHz Four Channel
100m 4-Channel 433MHz Wireless RF Remote Control
 
200m 4-Channel 433MHz Wireless RF Remote Control

Having the ability to control various appliances inside or outside of your house wirelessly is a huge convenience, and can make your life much easier and fun. RF remote control provides long range of up to 200m / 650ft and can find many uses for controlling different devices, and it works even through the walls. You can control lights, fans, AC system, computer, printer, amplifier, robots, garage door, security systems, motor-driven curtains, motorized window blinds, door locks, sprinklers, motorized projection screens and anything else you can think of.
100m 4-Channel 433MHz Wireless RF Remote Control

Four button RF remote is used to turn ON / OFF four different devices independently. Any of the four outputs can be configured to work independently in either toggle or momentary mode. Outputs are buffered by BC549 NPN transistors and can drive low voltage devices directly or be connected to either 5V or 12V relays (or motors) to control appliances that use 110V / 220V mains voltage or any voltage of your choice. Multiple remote systems can be used independently to control more than four appliances in the same location by changing the address code on 433MHz receiver and remote. It is also possible to use several remotes to control the same appliance such as garage door.
 

Electronics-DIY.com © 2002-2014. All Rights Reserved.