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.

Tuesday, December 22, 2015

VHF RF Choke

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Home made VHF rf choke. It has a typical value of 0.3uH made by winding 15 turns of 0.2mm enamel wire over a high value resistor (27K 1/2...

Thursday, September 17, 2015

FM Broadcast 55W Push-Pull RF Amplifier

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This prototype rf amplifier uses two 2SC2640 VHF power transistor wired in push-pull configuration. The 50 ohm impedance of the input...

12 comments:

Friday, September 4, 2015

Quarter Wave Stub Demo

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One of the trick that you can perform to your friend (not a Ham) is this quarter wave stub. Looking at the DC (direct current) point of vi...

1 comment:

Wednesday, August 26, 2015

Telephone Audio Coupler

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This circuit is a simple one, audio signal from the telephone line is sampled by the 600:600 ohm isolation transformer. The combination ...

Sunday, July 13, 2014

4:1 Unbalance to Unbalance Coaxial Transformer

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This is my first time to implement the 4:1 unbalance to unbalance coaxial transformer to match the input and output impedance of...

3 comments:

Monday, June 30, 2014

Experiment With Different Wind Turbines

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Two months ago I was tasked to build a wind generator that can be use to charge batteries and power LED lights here in our main office. The ...

Thursday, June 5, 2014

Callsign Plate

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Beautiful callsign plate which I got from Philippine Amateur Radio Association (PARA) last year. The price is much cheaper than the one f...

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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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