Does anyone know about Network Rail's proposed GSM-R in-cab radio
system?

It's meant to be based on GSM, but seems to require many more, and
much bigger, masts. GSM masts, which typically are no more than 15
metres (49 feet) high, have a theoretical range of up to about 35
kilometres (22 miles). So one mast could in theory cover a total
distance of 70 kilometres.

GSM-R masts are more than twice as high (33 metres or 108 feet) and
Network Rail wants to place them on average 7.9 kilometres (4.9 miles)
apart.

Can anyone explain this, please?

Chris

theoretical range of up to about 35
kilometres (22 miles). So one mast could in theory cover a total
distance of 70 kilometres.

As you said, its theoretical range so maybe they want to ensure that they
get good reception as train safety may be an issue.

Maybe post this to the Nortel newsgroup (if its still going) as I think
Nortel maybe providing the BaseStations for this but dont quote me on it.

theoretical range of up to about 35
kilometres (22 miles). So one mast could in theory cover a total
distance of 70 kilometres.

As you said, its theoretical range so maybe they want to ensure that they
get good reception as train safety may be an issue.

Maybe post this to the Nortel newsgroup (if its still going) as I think
Nortel maybe providing the BaseStations for this but dont quote me on it.