Re: FM to AM converter - variation on a theme!
Hello,
Thanks for drawing that out for me, it's not quite right I've attached a JPG.
The FM unit I have measures (front panel dimensions) 105mm(W) 25mm(H) 30mm(D). The PCB is approximately 70mm(W) 25mm(D)
I've been using this for a week or so now, sometimes all day sometimes just for an hour. It seem really stable and the AM frequency does not drift. The only thing I can fault it with is that the auto-tune for the FM channels does not seem to have an edit facility to get rid of the false positives so it detects 25 presets, but only 5-6 are actually stations!
The 150uh is one of the miniature chokes (looks like a 1/4w resistor), so is the 1mh
Ignore the black line in the middle of the JPG! it's just the PSU connections that should be different.
Further info, I did run the unit from 8xAAA batteries (most are capable of 500-700mha, so at around 25ma they should last around 24 hours continuous use)
I decided the PP3 would not keep in running long enough. And it the end the PSU option was far better for me.
Derek
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