Why not AM radio?

[maixiu]

Just a rhetorical complaint, but why is AM ignored on PMPs? Between talk radio, sports, radio theater, and, yes, music, I listen to AM more than FM. I would love to see AM radio as a feature on my P3.

[CrowdAds]

[triarii117]

AM isn't as popular.

[giggabotch]

The problem with putting AM tuners in digital pmp's is noise. AM receivers are susceptible to interference caused by components found in all digital mp3 players. The only way to make AM workable would be to shield an AM tuner in the PMP. There is only one player that I've heard about that can do this, at great cost, I don't remember the name of the company off hand.

[triarii117]

AM is really noisy and doesn't get very good reception from my experience with it.

[giggabotch]

Yes AM, Amplitude Modulation is more susceptible to noise than FM, Frequency Modulation.
Because of this magnetic fields can cause interference. Things like florescent lights, light dimmers, streetcars, computers etc. AM is less effective with signal penetrating buildings made with concrete and steel. It is, however, superior when in comes to geographical reach.

[The DarkSide]

It also requires a much larger antenna, and the HP cable will not suffice. It's actually a Ferrite rod. It would make the device much larger, and slim seems to be in.

Quote: The antenna inside most modern AM radios is a ferrite rod with a coil of wire wound around it. A booster in the form of a balance dipole antenna and ferrite coupler can be used to magnify incoming signals into an AM radio ferrite antenna to improve its reception.

Read here: http://www.abc.net.au/reception/radio/am_antenna.htm

PS: I did a WiKi and really couldn't find anything better, and another link would be grateful.

[MojoPatrol]

Originally Posted by giggabotch

The problem with putting AM tuners in digital pmp's is noise. AM receivers are susceptible to interference caused by components found in all digital mp3 players. The only way to make AM workable would be to shield an AM tuner in the PMP. There is only one player that I've heard about that can do this, at great cost, I don't remember the name of the company off hand.

Just out of general curiosities sake, how would they shield the AM tuner? Would they have to encase the tuner within a heavy metal casing or something? I only ask because I don't know much about radio transmitters and I'm interested in learning about anything

[sumx4182]

Originally Posted by MojoPatrol

Just out of general curiosities sake, how would they shield the AM tuner? Would they have to encase the tuner within a heavy metal casing or something? I only ask because I don't know much about radio transmitters and I'm interested in learning about anything

I'd like to know more about this because as an EE...I don't know of an effective way to sheild an antenna because you would then be blocking out not just the EMI, but also the waves that you are trying to capture. Doesn't make much sense to me.

[MojoPatrol]

Originally Posted by sumx4182

I'd like to know more about this because as an EE...I don't know of an effective way to sheild an antenna because you would then be blocking out not just the EMI, but also the waves that you are trying to capture. Doesn't make much sense to me.

Yeah I was kind of wondering about that...

[sumx4182]

i know you can perferate the shield to only block certain frequencies (the same way your microwave has a perferated shield a certain fraction of the wavelength to block microwave radiation from escaping the inside of the oven. But I highly doubt anyone would go to that trouble to get an AM radio in a PMP, or if it would even work at all because you probably can't block radiation both higher AND lower than the AM band, just the longer wavelenths but not the shorter ones.

EDIT: Let me clarify...the perferations block any wavelenths larger than the size of the perferation. Thus, any wavelenth smaller is allowed to pass. In the example of the microwave, the radation is approximately 4.2 inches in wavelength, much much longer than the size of the perferation and is thus blocked from passing through the plastic window. AM's longest wavelength is over 22,000 inches. So that would have to be the size of the perferation to block longer wavelents and thus, would only block waves below 530 KHz. All higher frequency noise (the entire FM band, UV, IR, Visible, Xray, Gamma ray...) would remain. Effectively, you only block long wave radio interference.

In other words, I call bullshit on this "shield".

[giggabotch]

Originally Posted by sumx4182

I'd like to know more about this because as an EE...I don't know of an effective way to sheild an antenna because you would then be blocking out not just the EMI, but also the waves that you are trying to capture. Doesn't make much sense to me.

Well you wouldn't have to shield the antenna but you could shield the pmp components from the antenna which would indeed make it a large player. Here's a link to one manufacturer who has done it.
http://reviews.cnet.com/mp3-players/c-crane-witness-am/4505-6490_7-33351260.html?tag=mncol;lst
As an aside, it'll be interesting to see how manufactures incorporate HD radio into portable players, Zune HD as an example. It looks like Zune will only be FM HD, but I wouldn't be surprised to see AM HD in a small package sometime in the future.
Where I live in Canada, it’s unlikely that we’ll see the Zune HD because there are no AM/FM HD broadcasters here because of technical hurdles that need be addressed in order to make it work here. That leaves Canadians with only two possible options if they want to listen to there beloved AM stations. One is streaming via wi-fi which, of course, has its limitations. The other is listening via G3 wireless access, which means burning wireless up minutes.

[sumx4182]

From my understanding, you can still tune to normal FM radio with an HD receiver. So for Canada...the Zune HD just won't have HD stations to receive but will do FM fine...unless I'm wrong, haha

And I thought you were talking about the antenna picking up interference...shielding components is a much different story. Components are shielded every day. There are many devices that have some sort of shielding because transistors are getting smaller and smaller, voltage tolerances are getting smaller and smaller, and thus the components get closer and alot more 0's start looking like 1's and vice versa due to interference. In fact, almost ever piece of consumer electronics probably has a shield or two, especially over the main processor.

[MojoPatrol]

Doesn't involve tin-foil helmates does it? Already went through that stage, didn't make many friends for it.

[The DarkSide]

Originally Posted by MojoPatrol

Doesn't involve tin-foil helmates does it? Already went through that stage, didn't make many friends for it.

It helped me get rid of the ex-wife though!!!

[giggabotch]

Originally Posted by sumx4182

And I thought you were talking about the antenna picking up interference...shielding components is a much different story. Components are shielded every day. There are many devices that have some sort of shielding because transistors are getting smaller and smaller, voltage tolerances are getting smaller and smaller, and thus the components get closer and alot more 0's start looking like 1's and vice versa due to interference. In fact, almost ever piece of consumer electronics probably has a shield or two, especially over the main processor.

Here's an experiment you can try. Take a battery powered portable AM radio and tune it to a clear channel frequency. Now take your P3, it doesn’t have to be playing audio, it just needs to be on. Hold the two units together, preferably the P3 on the underside of the radio were the antenna more likely to be. You should here a whining sound. That's where the difficulty of adding AM to pmp lies. It's true that the FCC requires a level of interference free operation of electronic devices. But those levels are mesured in feet as opposed to inches or less or pmp's.

[jjrosaria]

who listens to AM now a days?? I mean seriously? I never even listen to FM.. Well except in the car sometimes

[Olley]

HD radio sometimes put's AM content on sub-channels. So in theory, the ZuneHD with it's HD radio might eliminate any need for true AM.

[The DarkSide]

Originally Posted by Olley

HD radio sometimes put's AM content on sub-channels. So in theory, the ZuneHD with it's HD radio might eliminate any need for true AM.

There are actually, in NYC, AM channels that are on the list of available selections. That allows you to listen to either AM news channels in FM quality, and FM stations in CD quality.

[MojoPatrol]

Originally Posted by The DarkSide

There are actually, in NYC, AM channels that are on the list of available selections. That allows you to listen to either AM news channels in FM quality, and FM stations in CD quality.

Madness I say! Sheer Madness! Some of our radio's you still have to wind up to get enough power to get AM

Na, just kidding, I wish we had HD radio. I wouldn't want to pay for it though lol

[dfkt]

Originally Posted by MojoPatrol

I wish we had HD radio. I wouldn't want to pay for it though lol

Or even better, how about not falling for some crippled proprietary non-standard like HD Radio, but using something open and freely available like DAB instead?

http://en.wikipedia.org/wiki/Hd_radi...d_incompatible

As always, the USA has to do their own thing vs. the rest of the world, same as with cellphone (non-)standards, NTSC/ATSC nonsense, and whatnot... rant over.