The Hidden FM Radio Inside Your Pocket, And Why You Can't Use It

[HarryT]

Originally Posted by Shane R

Probably a battery life issue. No need to look for conspiracies where they don't exist.

An FM radio uses considerably less battery power than streaming music over 3G or WiFi.

[faithbw]

Originally Posted by Shane R

Probably a battery life issue. No need to look for conspiracies where they don't exist.

The article linked to in the OP said that FM radios use less battery power than streaming.

"Listening to streaming drains your battery three to five times faster than listening to the exact same content on the FM chip," he says.

[jbjb]

Is there anything to suggest that the smartphones in question actually have all the hardware needed to receive and play FM, as opposed to just having a Bluetooth/Wi-Fi chip that also happens to have FM capability? There's more to an FM radio than just having a chip with an FM receiver - you'd need the appropriate antenna, associated circuitry etc.

/JB

[faithbw]

Originally Posted by jbjb

Is there anything to suggest that the smartphones in question actually have all the hardware needed to receive and play FM, as opposed to just having a Bluetooth/Wi-Fi chip that also happens to have FM capability? There's more to an FM radio than just having a chip with an FM receiver - you'd need the appropriate antenna, associated circuitry etc.

/JB

It sounds like there are actual FM chips that work but that are deactivated by the phone makers:

But the FM chip is not activated on two-thirds of devices. That's because mobile makers have the FM capability switched off.

Most smartphone models come with a built-in FM feature. Samsung, Apple and LG are among those who have not switched on the chip, but HTC and Motorola chips haven't been blocked, Smulyan says. Sprint has turned on the FM chip for phones on its network.

[AnotherCat]

Originally Posted by jbjb

Is there anything to suggest that the smartphones in question actually have all the hardware needed to receive and play FM, as opposed to just having a Bluetooth/Wi-Fi chip that also happens to have FM capability? There's more to an FM radio than just having a chip with an FM receiver - you'd need the appropriate antenna, associated circuitry etc.

/JB

You are correct.

A typical example in a higher end smartphone is that the FM antenna is the headset cord and the audio left and right conductors in that used as the antenna. In the phone there will be antenna impedance matching circuitry and electrostatic discharge (ESD) protection to match the antenna input to the receiver antenna input impedance in the connectivity IC which may be capable of supporting all or some of Bluetooth, Wi-Fi (WLAN), FM Receiver, FM Transmitter, UART. The headset cord conductors used as the antenna also have to be isolated from the connectivity ICs audio output as those conductors are common to both the connectivity IC's FM antenna input and its audio outputs.

The ESD, matching and isolation is all specifically required for the FM radio and, of course, also entails the cost of a more complex circuit board and higher costs of assembly.

So the people who are just describing the need as just being "switching the chip on" are dreaming. Also, of course, the phone manufacturer has to consider their markets and I suspect those are telling them that there is limited demand, or that the demand is only within certain geographic regions or price points; in which case including FM radio receiving capabilities is pointless.

There may, of course be other capabilities within the phone which are not enabled for similar reasons

[theducks]

You would also need a matching FM tuner App to control it.

No app, and even if the chip/circuitry was there
So many ways to force the higher revenue method. Just block rooting the device.

[AnotherCat]

Yes there is the software development cost as well.

Harry has mentioned differing regulatory requirements for type approvals; aligned with those are also the differing band plans for the spectrum used for FM broadcasts around the world as well as the differing channel center frequencies used.

So it is easy to see why this all may be just to costly if there is not much market demand and why it may be that only phones going to one or some parts of the world are supported and the rest not.

Regarding regulatory requirements for other functions:

GPS is another which has, of course, been disabled in phones because of regulatory requirements but less so now (without any checking by me I think only Syria and North Korea left now, but I recall Egypt was toying with doing so too, but don't recall where that got to).

WiFi has also been disabled as not allowed in some countries but without a search am not sure who left now.

Originally Posted by theducks

You would also need a matching FM tuner App to control it.

For one of my phones, that was exactly the case. After Cyanogenmod was installed, I had a phone with an FM radio.

[AnotherCat]

Originally Posted by BWinmill

For one of my phones, that was exactly the case. After Cyanogenmod was installed, I had a phone with an FM radio.

Just out of interest was that the OEM's version of the phone or one produced by the OEM for a cellular service provider? And if so was it in the USA where such phones are often considerably different to the international base model?

Thanks.

John

Originally Posted by AnotherCat

Just out of interest was that the OEM's version of the phone or one produced by the OEM for a cellular service provider? And if so was it in the USA where such phones are often considerably different to the international base model?

It was a Samsung Galaxy Gio S5660 produced for a Canadian carrier.

[AnotherCat]

Thanks.

It must be a carrier exclusion or local regulatory matter as the phone in standard configuration has an operational FM radio .

John

[AprilHare]

Originally Posted by HarryT

AM radio uses much longer wavelengths and hence needs a longer antenna, which probably isn't practical for a phone.

The antenna for AM radio are much smaller actually. They are often embedded in devices. It's FM that requires an external antenna.

Originally Posted by AprilHare

The antenna for AM radio are much smaller actually. They are often embedded in devices. It's FM that requires an external antenna.

Uh, no. AM radios with embedded antennas usually use really long coils of wire to account for the longer wavelength. While you can make these coils much more compact, they are more expensive than the "long wire" antennas typically used by FM radios.

[theducks]

Originally Posted by AprilHare

The antenna for AM radio are much smaller actually. They are often embedded in devices. It's FM that requires an external antenna.

Many portable AM Radios used Ferrite Loop stick antennas . These were small(ish), but very directional. You had to 'Aim' the end of the 'stick' at the station

[cromag]

"Loop sticks" are also pretty heavy -- on a cell phone scale, at least.