A very good Jo story and love how Benton feels like part of the tardis team in this too

A signal from space and the beginning of mobile phones?

It has all the classic motifs of 70's 3rd Doctor stories - the Doctor fiddling with some technology of his own interest, the Brigadier wanting his help with some scientific research and
the weird electronic music.

At the start an alien race is trying to message earth, then a couple of minutes later the Doctor announces he's recieving a signal, but there's a musical 'sting' after he says 'Its not from Earth' it seems a bit odd when we know that already.

Early on Jo seems a it more confident and forthright, it seemd a little unlike Jo of the time I was going to make a point about it, but even the Brig is a little taken aback, so actually its a nice moment.

It doesn't really get going until part 3 and I feel that the first two could have been condensed into one part.

Its great to hear John Levene as Benton, I don't think he's done much for Big Finish, but he wasn't used enough! later in the story he was just in the background.

I was tired when listening to episode 4 so didn't take it in so much, but generally enjoyable.