On Thu 2 Jul 2009 12:11, Larry Johnson pondered:
In the United States, most radio transmitters must be type accepted (certified) by the Federal Communications Commission. Modification voids the type acceptance, so operating a modified mobile phone on its original frequencies would be illegal regardless of what the phone company's rules say. However, no certification is necessary for transmitters operated according to the rules for the Amateur Radio Service. Thus, an licensed amateur could legally use a modified mobile phone, provided it transmitted on frequencies allocated for amateur radio and met the other requirements for amateur operation, including not causing harmful interference to other services.
Assuming that the _licensed_ amateur could modify the phone enough that it _could_ operate on frequencies allocated for amateur use.
The only thing that would be potentially close is a European GSM phone:
Rx Tx E-GSM-900 880.0–915.0 925.0–960.0 MHz R-GSM-900 876.0–915.0 921.0–960.0 MHz T-GSM-900 870.4–876.0 915.4–921.0 MHz
& the US amateur band at 902 - 928 MHz.
I don't think any of the CDMA phones are close enough to the amateur bands to have a hope of working - but I'm not as familiar with CDMA as GSM.