"Robert11" wrote in message
...

Other than using a square tipped shovel (or forcing my kid to do it), was
wondering if anyone has any "clever" ideas
on other possible ways of digging this very narrow (slit type) of trench ?

Getting on inyears now, and it sounds like a lot of work.
Is there some tool other than the shovel that I might rent, or... ?

Ditch Witch trencher. You can go down a few feet with them. There are
codes for electrical wires, but coax may not have to be so deep as it is not
current carrying.