Circuit Lake » Ham Radio

Low Picofarad Capacitance Meter

admin — Wed, 31 Aug 2011 05:40:19 +0000

This little instrument, named as Pico C, can be used to measure capacitances down to fractions of a picofarad. It built based on ATtiny2313 microcontroller. It has range: <1 pF to 2000 pF (guaranteed); 2500 pF possible and resolution: 0.1 pF. To read the result, this low cost C meter comes with 2 lines [...]

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Crystal Radio With External Speaker

admin — Thu, 07 Apr 2011 00:37:10 +0000

Crystal radio is the simplest type of radio receiver, and can be handmade with a few inexpensive parts, like an antenna wire, tuning coil of copper wire, crystal detector and earphones. It needs no battery or power source and runs on the power received from radio waves by a long wire antenna.However if you [...]

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PLL FM Transmitter with PIC-Based Tuning

admin — Tue, 01 Mar 2011 06:02:07 +0000

This easy to build PLL FM transmitter can deliver RF power output typically of 5 Watt. The project uses PIC16F627A to control PLL IC TSA5511 during FM Tuning process. PLL in-lock state status is displayed on LCD or you can check it on LED indicator (when LCD not connected).The transmitter can be used with or [...]

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FM Transmitter with a Single Transistor

admin — Thu, 03 Feb 2011 17:46:33 +0000

Here is the most stable, smallest, and energy saving FM transmitter. It uses only single transistor oscillator, PN2222A. Other high frequency / low noise transistor like 2N2222A, BFxxx series, BC109B, C, and even well known BC238 could work as well. Key to a well functioning, low consumption circuit is to use a high hFE / [...]

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Frequency Marker Generator

admin — Sun, 06 Jun 2010 20:38:37 +0000

COLT45 is a small multi-purpose device intended for the Amateur Radio operator, short wave listener, or other experimenters. Functions include a versatile frequency marker generator, a Morse code keyer, and a Morse code beacon generator with room for more functionality.The Colt45 uses an 8-pin Atmel AVR ATtiny45 microcontroller. To produce these precise low frequency square [...]

Portable Spectrum Analyzer

admin — Sat, 16 Jan 2010 18:51:41 +0000

If you have ever attempted to do any projects that involved UHF/VHF frequencies, what is immediately apparent is that your normal test equipment is very inadequate. Standard TV signal space, for example, runs from 50 to 878 MHz. The cost of acquiring test equipment that operate at those frequencies, like signal generators or an oscilloscope, [...]

AVR Embedded Antenna Analyser

admin — Sat, 20 Jun 2009 02:55:56 +0000

How to build Antenna Analyser for ham-radio? this project will show you how to build it. The IW3HEV antenna analyser is a relatively simple antenna analyser designed by pa3ckr. The main part of the project is Microcontroller AVR Atmel ATMega32. It has a 1-60MHz DDS signal generator and uses a homebrew directional coupler plus the [...]

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