Ask HN: Sim card control frequency?
Does the sim card control the frequency transmitted? And does the transmitter in the phone allow for a large range of frequencies, like from below 900Mhz up to and past wifi (2.4Ghz)??
It appears that the handset can request information from the SIM about frequency bands. For example, see section 10.3.38 of 3gpp specification #11.11 "Specification of the Subscriber Identity Module - Mobile Equipment (SIM - ME) interface", which discusses EF_CPBCCH: "CPBCCH storage may reduce the extent of a Mobile Station's search of CPBCCH carriers when selecting a cell" https://portal.3gpp.org/desktopmodules/Specifications/Specif... [click 'versions' and then the link '8.14.0' to get a zip of a doc file that renders like hell in libreoffice 5 on debian stretch]
However, after that I lose myself in random standards document and can't give a clearer or more authoritative answer.
If you want to transmit on an arbitrary frequency you'll need to buy a software defined radio, like the HackRF http://www.kr4.us/HackRF-One.html?gclid=CJGdyMDLqtQCFYGUfgod...