2007-01-13
"2007 80m Homebrew Challenge"
ARNSW is running an 2007 80m homebrew challenge this year. Essentially the challenge is to build before July 2007, a 20 Watt PEP, AM modulated (A3E) transmitter for 3.6864 MHz. Additional conditions of the challenge include that the transmitter must be in an single enclosure, and include the mains derived PSU internally. It must also provide a mechanism to mute an external receiver.
I decided to extend the challenge for myself a little, adding an internal receiver to complete a full transceiver. I figure by doing this I am more likely to use the finished product. Ideally I want a completed box that has a mains lead and an SO-239 on the back, and a 4-pin mic plug, AF gain, Mic gain and power switch on the front.
This page documents my progress with the challenge.
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Progress
- 2007-03-03: Circuit Diagram
- The circuit diagram for the transmitter so far.
- 2007-02-25: Exciter in a Box
- I put the 4 Watt exciter in an Aluminium box.
- 2007-02-24: 4-5 Watts PEP
- IRF510s arrive and I build a TX power-chain.
- 2007-02-18: Wyong and Receiver Thoughts
- I go to the CCARC field day and think about different RX topologies.
- 2007-02-17: A Working Receiver
- I get the TX talking to the RX and true First-Light for the Receiver.
- 2007-02-07: AM Receiver IF Development
- I start building the RX side of things.
- 2007-02-05: Building the AM Modulator
- I build the AM exciter, including crystal oscillator and speech amp.
- 2007-01-31: A3E Modulation
- I decide on low-level AM modulation, design and breadboard an AM modulator.
- 2007-01-28: I Visit ARNSW
- Clarification on the Challenge requirements means a completely different approach.
- 2007-01-24: 1 Watt DSB Transmitter
- I complete a 1 Watt DSB transmitter lash-up.
- 2007-01-13: Initial Thoughts
- I first read about the challenge on the ARNSW website.