du1vss (D.I.Y.)

It's all about ham radio. Although some of my projects involved transmitters, rf amplifiers and antennas that operate outside the ham bands, these things are solely for educational purpose only and experimentation.

Wednesday, July 20, 2011

Homebrew 30W FM Broadcast Amplifier

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The original diagram was taken from the data sheet of Mitsubishi 2SC1946A designed to operate at 175MHz. Both input and output t...

2 comments:

Monday, June 20, 2011

Collinear antenna for FM transmitter

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This collinear antenna works perfectly after the installation. The antenna is basically two dipoles excited in-phase and theoritically e...

1 comment:

Sunday, November 7, 2010

Amateur Radio Exam Result, October 2, 2010

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Feels good to have a new ticket. I would like to give thanks to my fellow hams (DX1CW) who have provided me the reviewers that made poss...

2 comments:

Friday, July 9, 2010

Automatic Battery Charger

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Here is a simple battery charger circuit intended for 12 Volt gell-type battery. Current is limited by the 7805 regulator IC and the...

Wednesday, June 16, 2010

OPC-478 Cloning Cable

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Another evening project is this OPC-478 cloning cable for my Icom IC-2200H. Credit is given to Icom which the original circuit ...

Thursday, May 20, 2010

Solid State Relay (SSR) using MOC3020

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The circuit uses the MOC3020 optocoupler that drives the triac to switch 220V of AC volt to a load. We have this project after one o...

1 comment:

Friday, April 2, 2010

Transmit Beacon for Hand-held Radio

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The circuit is run by 555 timer IC for its PTT sequence that is 4 seconds "on" and 4 seconds "off". Transmission...

3 comments:

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About Me

hevirred: Hello, I'm Vir, a ham radio operator with a callsign of DU1VSS. I hope you find this blog useful and interesting. Feel free to send me an email if you have questions about my project. Thank you and 73. hevirred@gmail.com

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