There is an inexpensive QRP kit that sells on eBay for somewhere between $4-10, called a Pixie. It is a single conversion rock bound 40 meter QRP rig often set to 7.023 MHz, but sometimes 7.040 MHz. They are often described as a 1 or 2 watt rig. I decided to purchase one to see how well it performs.
In various tests, I did manage to blow out the 8050 final amplifier device, and I can tell you running it at 13.8 volts is probably a big mistake as it leaves that device dissipating about 2 watts — far beyond its rating. On the other hand, 10.4 volts (which puts the internal power rail at about 9 volts) is probably a bit on the low side. My unit does not pass FCC emissions requirements (spurious emissions must be -43 dBc). And being Direct Conversion, a lot of power leaks out the antenna on transmit.
- Pixie is driven with a 10.4 VDC power supply (and consumes 10 mA in receive and 60 mA in transmit)
- Output power measured with a QRP watt meter is 140 mW at 10.4 VDC input.
- Pixie is terminated with a 50 ohm dummy load.
- The Oscilloscope is in parallel with the dummy load (1x probe setting)
- The Spectrum Analyzer is fed with a 40 dB external attenuator.
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