On Thu, 15 May 2003 06:41:53 +0100, Oz
wrote:

EEng writes

Years ago I designed a similar system for the Japanese Dept. of
Agriculture with the added feature that each station could be remotely
programmed for priority readings, and instead of a mobile phone, each
station had its own VHF transmitter.

Radio networks *might* have enough range in electrically quiet areas and
modest field sizes.

2 mile range. Japans Ag Center is just outside Osaka. Electrically,
not quiet at all. No complaints to date.