radio feature in nokia phone

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mdanh2002

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In most nokia phones, there's a radio feature. However when turned on it says "needs enhancement". The enhancement basically just contains an antenna and 2 earphones. I am just wondering why the manufacturer didn't design the antenna as part of the built-in circuit and allows the user to play the radio through the speaker? Why do they need an extra antenna, for stronger signals? Or maybe to force the customers spend more on the enhancement? Will there be any technical issues when the FM antenna is part of the built-in circuit? It would be better if you can just listen to radio through the loudspeaker without the needs for an external enhancement.
 
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An aerial for FM frequencies needs to be about 750mm to work properly and your phone is far to small to fit one in. Normally the aerial is built into tho the headphones.
 
The wires for the headphones is the antenna for the FM radio.
I don't think cell phones have an AM radio.
 
I wonder how small you COULD make an AM tuned circuit? The Q would be pretty rotten but you could use an electrolytic for the cap, making the ferrite core needed much smaller. (not that anyone would be interested in an AM receiver in a cell phone anyway)
 

it's definitely a design to encourage users to purchase the accessories. it's just a happy coincidence that the FM receiver will benefit from the antenna provided by the headphone cable
 
TheVictim said:
but you could use an electrolytic for the cap
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No way.
Electrolytic capacitors just dont work at high enough frequencies.
Also, you would be able to get enough capacitance using dielectrics more suited to RF use.

JimB
 
It probably is possible to intergrate AM radios into mobile phones but it isn't the done thing because not very many people listen to AM radio.

DAB would be a better option as most AM stations also broadcast on it and it would be more useful in general.
 
Hero999 said:
DAB would be a better option as most AM stations also broadcast on it and it would be more useful in general.
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Except it has useless coverage, with many ares of the country getting no DAB at all, and where it does work it tends to be fairly patchy. Not to mention that FM is far better quality anyway!.
 
Here in Estonia there probably aren't any AM stations left. all are FM.
And why are you whining about that headset? you have to use it anyway to LISTEN to the radio, don't you?
 
TheVictim said:
In 2009 our analog TV broadcasts are going to bite the dust. At 6Mhz per channel, I can see why.
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Yes, it's far cheaper for the broadcaster to transmit lower quality digital signals - and hopefully not too many viewers will complain!
 
My problem is I have many Small FM kits manual tuning and digital tuning ones but it doesn't have any external antennas but its working perfectly with built in small antenna.

Phone manufactures can design the phones by adding some options like this..

*If you turn on the radio feature its opening without need a headset.
*If no signal strength can plug the headset and listen too.

So have two option's.
 
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Hero999 said:
An aerial for FM frequencies needs to be about 750mm to work properly and your phone is far to small to fit one in. Normally the aerial is built into tho the headphones.
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My 512MB portable MP3 playable is much much smaller than the phone and yet can still afford a built-in antenna for its FM radio. I believe the design of an external antenna is just to force the consumer to buy the accessories. However, my phone's FM sound quality is much better than that of my portable MP3.
 
bloody-orc said:
Here in Estonia there probably aren't any AM stations left. all are FM.
And why are you whining about that headset? you have to use it anyway to LISTEN to the radio, don't you?
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Here in Singapore there are totally no AM stations. However in some places I can receive AM signals from nearby countries such as Malaysia. On the other hand the FM band is almost crowded: a portable manual tuning radio will not be selective enough to tune in the exact station.
 
are you 100% sure, that it has an internal antenna? It also probably uses the headset as an antenna. Like said before, FM needs a long antenna, that you just can't fit into a small MP3 player (or a mobile phone)
 
I also thinks that it requires external antenna but then my MP3 player doesn't require its own headset - it just has a normal jack and you can use any earphone. Can it be the case that the device is designed to use the earphone wire as antenna?
 
mdanh2002 said:
I also thinks that it requires external antenna but then my MP3 player doesn't require its own headset - it just has a normal jack and you can use any earphone. Can it be the case that the device is designed to use the earphone wire as antenna?
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Yes, it's common practice!.
 
That has been common just about as long as portable FM stereo players have been around. The earliest FM Walkmans used the headphone wires as the antenna.
 
So are there any similiar reasons while mobile phones don't have an AM radio? Is it only because AM has become obsolete?
 
Probably but AM isn't totally obsolete, there are quite a few AM stations where I live and AM is also useful for mountainous areas where FM won't travel well.
 
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