For an electronics class we're being asked to build a kit from RadioShack. It's the "Mobile Phone-Styled FM Radio Kit" catalogue number 28-289. I've been trying to find some circuit diagrams of simple FM radios but there seems to be a wide variety of circuits used. If anyone has info on this or just circuit diagrams of a very simple FM reciever that would be fantastic. Over and OUt
You might try suppliers like Ocean State Electronics, Jameco and others. They sell kits - FM, AM, other. Some of them have a section in their website where they offer the manuals or schematics for download.
The RadioShack FM radio probably uses the TDA7088 IC that uses scanning for its tuning. The IC is made by Philips and by Unisonic. Look in Goggle for their datasheets that have the schematic of the radio.
How first need to decide (or at least explain?), what you're trying to do. The broadcast FM band is wideband, and other bands are likely to be narrowband, so you need at least two different IF and demodulator systems.
I have never seen a TDA7000 FM radio IC. It has not been made for many years.
I have some FM "radios" that use the TDA7088 FM radio IC. Their performance is terrible. They pickup local FM stations with distortion. They don't pickup distant stations like an ordinary radio.
When you buy something that is cheap, usually the performance of it is also cheap.
A real FM radio is extremely sensitive but does not overload from very strong local stations, has extremely good selectivity so it can pickup a weak station that is beside a very strong station on the dial and has very low distortion.
Service manuals for very high quality hi-fi radio receivers are available on the internet. You can't make them because you can't buy all the special parts they use.
My first hi-fi radio FM tuner was a kit and it worked perfectly. It was good quality that is not produced anymore. The radio kits available today are just simple and cheap child's toys.
A radio schematic is useless because you can't buy the special RF transistors, tuning inductors, tuning capacitors, IF transformers and crystal filters, IF amplifier IC, FM detector transformer or crystal filter and stereo decoder IC.
Buy a radio, take it apart and use its parts to make your own radio. It won't work unless you are experienced in making a radio.
A radio schematic is useless because you can't buy the special RF transistors, tuning inductors, tuning capacitors, IF transformers and crystal filters, IF amplifier IC, FM detector transformer or crystal filter and stereo decoder IC.
Buy a radio, take it apart and use its parts to make your own radio. It won't work unless you are experienced in making a radio.