UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - FM to AM converter

David G4EBT · 18th Oct 2018, 7:01 pm

Thanks Lawrence.

The fewer components the better, consistent with good design, but if I omitted the two caps on the input to R4, (or rather reposition them to the downstream side of R4 at the Junction of R4/L2, instead of adding the two caps I’ve called C9/C10), wouldn't that then be as Joe suggested in post #38 and as I depicted in post #39 by deleting one section of track and adding another?

@ Joe: Thanks for mentioning the resistors for the combined L&R inputs (as per the Mini Mod). Good suggestion - I don't think Derek did it, but it's no hassle. I won't complicate the PCB by trying to add them there - I'll fit them into the centre terminal of the 3 terminal socket and connect the flying leads from the FM module. I don't want to make the PCB any longer than 9.4cms as I want the fixing holes to line up with the module.

I have in mind to make a small bespoke wooden 'box' with rounded ends in which to house the converter, something like that in the sketch below.

18th Oct 2018, 7:01 pm	#43
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,767	Re: FM to AM converter - variation on a theme! Thanks Lawrence. The fewer components the better, consistent with good design, but if I omitted the two caps on the input to R4, (or rather reposition them to the downstream side of R4 at the Junction of R4/L2, instead of adding the two caps I’ve called C9/C10), wouldn't that then be as Joe suggested in post #38 and as I depicted in post #39 by deleting one section of track and adding another? @ Joe: Thanks for mentioning the resistors for the combined L&R inputs (as per the Mini Mod). Good suggestion - I don't think Derek did it, but it's no hassle. I won't complicate the PCB by trying to add them there - I'll fit them into the centre terminal of the 3 terminal socket and connect the flying leads from the FM module. I don't want to make the PCB any longer than 9.4cms as I want the fixing holes to line up with the module. I have in mind to make a small bespoke wooden 'box' with rounded ends in which to house the converter, something like that in the sketch below. Attached Thumbnails __________________ David. BVWS Member. G-QRP Club member 1339.