Owing to a fast decline of medium waveband broadcasts and a continuing interest with vintage AM radios, Guy Fernando (M0OOX) presents this cost effective design for enabling FM broadcast stations to be listened to on classic vintage AM radios.

Introduction

AM broadcasts in the United Kingdom and the rest of the world are in rapid decline and are likely to cease altogether by the middle of the 2020s, mainly due to higher transmitter running costs and dwindling listeners. Many countries in Europe have already closed AM broadcasts completely. Here in the UK on the long wave band (148.5 - 283.5kHz) only BBC Radio 4 can be heard. On the medium wave band (526.5 - 1606.5kHz) there remain a few regional and commercial stations that can be heard, but the only nationally covered stations are BBC Radio 4, and Radio 5 Live. It is however a different story on the FM band (87.5 - 108.0MHz). At least for the foreseeable future, there remains a wider selection of FM stations including regional, community and the national BBC stations, Radio 1, Radio 2, Radio 3 and Radio 4 FM.

It is feared, with the imminent closure of the AM band countless vintage radios will become aesthetic curios or worse end up in skips - FM to AM converter to the rescue! These types of converters were widespread in the 1960s and 70s and sold mainly as AM car radio adapters, but have now disappeared into obscurity and the few that are still being manufactured are fairly costly owing to the niche market at which they are pitched. It is hoped this simple converter design described here will offer a new lease of life to AM only radios without breaking the bank.

Building the FM to AM Radio Converter

The converter is simple to build and should not pose any problem to the seasoned constructor. There are two ways to build the converter. It is offered as a kit, comprising of a professionally manufactured printed circuit board (PCB), with pre-programmed PIC, and all the other components to enable you to build a working converter. Alternatively just the pre-programmed PIC is available for constructors that choose to build their own converter on stripboard.

Further useful information regarding project may be found at UK Vintage Radio Repair and Restoration forum.

Full design details for both build methods are presented below.

• Kit Build
• Stripboard Build

After dispatch, the order can be tracked using the Royal Mail Track your item service.

Happy listening!