[Boatanchors] Relay specs?

[Eugene Hertz]

Hello all,

got this nice (huge) relay on the not-to-be-mentioned place. I am thinking of using this to short an inverted L to ground when the antenna is not in use. I plan to locate this relay remotely at the base of wire antenna between the remote tuner and the wire.  You can see it, item number 290002597527  Relay stands about 6" high. BTW: there are no marking on it.

Any way. Seller thought this was 120VAC, but I seem to be able to actuate the relay with 6VDC which makes a draw of about 750ma.  How does one determine what the "right" voltage for such a relay is? 

And how (if) does one determine if there should be some current limiting resistor or something and what about ac vs dc?

Thanks
Eugene