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| All design ideas from the EMRFD book. Thanks to W7ZOI, KK7B, W7PUA. And i'm blessed to get this book in India at a second hand book seller. I told him to reserve any radio related books, one fine eve he called me about this book. I also bought ARRL 2011 book. If i'm not using the design concept from this book, then its a shame on having the book. So, here is my QRP Project.. |
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| 1st design requirement is, front facing 4" speaker. No compromise. |
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| I wanted this to be a self powered, no need to search for DC adapter. The transformer salvaged from old HI-FI cassette player. 15V 2A. I used 12V regulated power supply for TIA chain. Rest using unregulated 17V. |
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| Close up view |
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| From right >> RX/TX antenna relay >> 40m BPf >> 1st TIA amp >> VFO diode ring mixer >>10MHz ladder filter >> 2nd TIA amp >> 10MHz BFO >> 2nd diode ring mixer >> 2N2222 preamp >> audio power amp > ULN2003 for all relay switching |
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| Transmitter stage. >> 2N2222 >> BD139 >> 2SC1971 >> 5th order LPF . 2SC1971 gives spurr free 5 watts clean output with 17V 2A. I connect SI5351 clock output directly to 2N2222. All are TV balun cores. Cause thats what i have. |
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| Side tone oscillator , Power supply and audio amplifier close up view |
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| This is my own SI5351 clock generator board using ATMega8. ( I Hate arduino. ). I'm using C language in this project, but assembly version is in progress. You can find details about this PCB on this blog, look for SI5351 DDS board.. |
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| The speaker is from old National Panasonic cassette player. Excellent audio quality. |
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| Etched TIA Amp board, i made about ten PCBs for future uses. Around 1" x 1" approx |
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| Initial layout. Modular PCB system makes very easy to assemble and troubleshoot. |
