iPhone OS 4 FM tuner

No one here has any idea. If this will be included with firmware update 4.0 and someone here is privileged to this info in advance, they are under Apple's non disclosure agreement and aren't allowed to say until Apple makes an announcement.

This is the only info Apple has released to date in regards to firmware update 4.0.

http://www.apple.com/iphone/preview-iphone-os/

OS 4.0 is a firmware update. A radio tuner is hardware. Current iPhones do not have FM tuners in them.

I recall reading a report about a 3GS teardown that the Broadcom wireless chip used with the 3GS has FM radio capability. If accurate, this may come standard with the chip without Apple having any intention on making use of it with a firmware update.

You are correct, the 3GS uses the Broadcom BCM4325 chip which integrates a complete IEEE 802.11 a/b/g system with Bluetooth® 2.1 + EDR (Enhanced Data Rate), and FM radio receiver.

No,

But most want an AM tuner.

Ahh. That would make sense.

Having a chip capable of FM reception is not enough - there has to be a suitable FM band antenna and the current iPhones lack this. Because of the frequencies of the FM band, the antenna has to be MUCH larger than the internal cell network, WiFI and Bluetooth antennas to get adequate signal.

The Nano and other phones that have FM use the wires of the headset as an external FM antenna. There's no indication that the current iPhones are wired to do this. It would also preclude having FM with Bluetooth headsets or using the internal speaker.

The Nano needs to use the headphones as an antenna. Without the headphones plugged in, the Nano would not get an FM stations.