[scorpio_rocks]

Yes, Yes and Yes.

From the game guide:

"Remember that an SP hex is 50 metres, about half a football field. 20 hexes is a kilometre (about 1000 yards for the non-metric folks). Units which have no radio will have to keep within 250 metres(yards) or so of their commander. Radios will work across the entire map, but are not 100% reliable. Remember that for radios to be useful communication aids that each party to the conversation requires a radio set!. (NB as time goes by in a campaign, your more experienced veterans will tend to pick up radios someone left lying about, even if radio chances are low for the unit in the OOB). Formation leaders get a higher chance of receiving a radio, as do artillery observers. In SP, radios can represent field telephones (in fortifications for example)"