It is !
by for instance using a "Powersplitter" (according to its name "splits" the input power applied to one of its "arms" (inputs) between two (or more) others. Tradeoff beeing a power loss of 3db (half of the inserted power) in each of the arms in case of the "3db splitter". Vice versa, two antennas may be connected to the output arms, and the input arm then to the receiver. A loss of 3db of input power (still talking about "power", even it is almost "tiny" input signals in case of a "receiver") the resulting tradeoff to both of the input signals again of course.
There are (expensive) "active" splitters available as compared to the above "passive" devices, suffering less "insertion loss", as compensated by means of amplification.
Another idea might be to use a "coaxial switch" at the end of both feederlines (as they come into your "shack"), thus manually selecting between one or the other antenna, or a "coaxial relay" (mounted "near" the antennas) to "directly" switch between them. Advantage beeing just one "coax" only to run down, disadvantage a "control voltage" to be supplied to the relay for its "switching" (Needs one "control" line, "ground" supplied via the coaxial cables outer conducter[shield])
Don't be "simple minded" by just connecting the coaxial feeder lines in parallel. It "works"
but is not a solution from a "high frequencies point of view".
Karl
