View Single Post
Old 27th Sep 2018, 1:17 pm   #9
coopzone
Hexode
 
coopzone's Avatar
 
Join Date: Jan 2018
Location: Cannock, Staffordshire, UK.
Posts: 268
Default 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
Attached Thumbnails
Click image for larger version

Name:	FM AM Converter MK2 Circuit with FM & MP3 Module.jpg
Views:	351
Size:	40.3 KB
ID:	169955  
coopzone is offline