earth

[almusic10]

this is a strange question, but if the earth was the size of say jupiter, how long would it take for a mobile phone signal or something like that take to get to the other mobile,

[Loosehead]

not noticably different. Need more satellites though!

[rojash]

Satellites don't normally come into it if the phones are in the same country. Signal travels by air from phone to nearest cellular aerial, then by landline to the cell in which the receiving phone is located, then by air to the phone,

[alvin100]

This is a really vague question but I think what you are really asking is how long would a signal between two radio type devices take to send and receive, after all a mobile phone is basically a posh walkie talkie.
Given that radio waves travel at about .97 of lightspeed in an atmosphere (ie very very fast) the signal could travel right around a planet in seconds, or even fractions of a second.
When you see or hear 'delay' in an audio or tv broadcast from the other side of the world, it is caused by the speed limitation of the various signal processing equpment (satelites, ground stations, phone exchanges etc) in receiving and retransmitting the signals, and not by waiting for the actual original transmission to arrive.

Hope this helps

Steve