cheap way to ad Chromecast to your 40's and 50's Televisions

[earlyfilm]

Originally Posted by cameronflyer

I cobbled this little contraption together for under $75.00.

OK, what would the benefit be of doing it this way have over cannibalizing an old VCR or such for a modulator, or even using a surplus agile modulator, which would seem to be less expensive and much less complicated.

Can someone explain this in analogue English?

I've seen Chromecast advertised, but the adverts never say what it does. As far as I know, no stores where I live carry them.

James.