[mictester]

I gave this a try – it works pretty well. The harmonic crud from the R Pi is horrid – the spectrum looks like a hedgehog on my analyser. Fortunately, the required signal is reasonably far away from the nearest spurious outputs, so by putting the R Pi in a screened box, using a critically tuned filter connected to the “aerial” pin and then using an MAR6 amplifier pill with a further critically tuned filter on the end, I was able to get about 350mW of clean signal. The worst spurs were -65dB ref carrier (which means that they’re in the µW range and won’t get much beyond the box! The whole thing is now housed in a neat metal box, and it makes a great little “house” transmitter for home use. The trickiest party of the whole deal is the screening and the supply filtering.

[mictester]

40 years as a radio engineer – offshore and on-shore. Will that do?

[Author]

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