Quote:
Originally Posted by ThePillenwerfer
The easiest thing would be to swap C1 and C8 'round.
The other thing that I'm wondering about is L1 and L2 being parallel and next to each other. Isn't there a risk that they'd form an ersatz transformer and interfere with each other?
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Thanks for reading the thread Joe, and for your comments.
The modulator part is exactly the same layout as the PCB I developed for the Guy Fernando Summer BVWS Bulletin FM/AM converter of which I've built 20 or so, which seem to be very stable and works really well. Many more will most likely have been built to Guy's strip-board layout and others on PCBs, with no reports of problems, so the proximity of the two little chokes seems not to have been problematical.
That project used the remarkable RDA5807M FM module and Guy's programmed PIC.
The only difference with this one is that Derek, ('coopzone'), used just the modulator section of Guy's design, which he built on strip-board and fed it from what is perhaps confusingly described on e-bay as a "Wireless Bluetooth MP3 WMA Decoder Board Audio Module USB TF Radio For Car". Basically an FM scanning radio with a digital display, a separate remote for changing stations, and allows for other inputs too.
The units are available for under a fiver from China but to save the delay, I bought it from a UK supplier for a couple of sovs more.
Clearly a drop shipper because payment went to 义乌市雅锐电子商务有限公司 !!
Should be here midweek, so as and when, I'll maybe knock up a board and give it a go.
Just doing it out of interest really - I'm more than happy with Guy's design.
Guy's design was powered from 2AA cells, hence, no need for the electrolytic. Derek included one here as this unit is powered via a wall-wart, which might introduce hum.
As Paul says, the aim is to keep things simple, consistent with acceptable performance.