On Apr 28, 5:26*pm, "Green Xenon [Radium]" <gluceg...@excite.com>
wrote:
> Hi:
>
> Most cell phones and wireless internet routers, modems, and access
> points that use spread spectrum usually broadcast and receive their data
> on FM-radio waves. Just out of curiosity, I ask, why not use AM?
>
> Let's say a DSSS/FHSS type of spread-spectrum is transmitted and
> received using the AM radio waves in the UHF spectrum [i.e. spread info
> for transmission throughout the UHF band and receive AM radio waves
> throughout all UHF frequencies]. What would be the disadvantages of this?
>
> Normally DSSS and FHSS are transmitted/received on FM radio waves. So I
> ask what would be the disadvantages of using AM instead of FM for this?
>
> AM radio tends to be more vulnerable to unwanted magnetic disruptions
> than FM, however this only affects analog reception. Digital reception
> on AM should be unaffected even by the strongest-interfering analog RF
> magnetic signal. Right?
>
> Thanks,
>
> Radium

Cellphones moved away from FM when they dropped analog service. IDEN
phones use a 4 subcarrier 16-QAM, but they are channelized and not
spread spectrum.