126,
an all band antenna, for the most part, is a compromise antenna.
an end fed random length wire is technically any random length of wire that is generally not fed with feedline. RF is applied to it directly in the shack (through a tuner). there is no feed line in this configuration, therefore, no feed line loss. the bad part is that you have RF right in your shack which can cause RFI to everything and you may have height restrictions.
a 'long wire' is one wavelength or greater in length for the lowest band you want to operate and usually fed at the end with open line wire (ladder line) and tuned with a tuner.
another antenna to consider is the G5RV...these are super easy to build and can be bought fairly cheap. these are good for guys who do a lot of shortwave listening or have antenna restrictions. they are not the best performers...but they get you on the air.
another option is a half wave length antenna for your lowest band of operation fed with ladder line and operated through a tuner.
it does not have to be any specific type of antenna...antennas are antennas, there are just different types of them. pretty much any type of antenna will work on any band, but there are practical limitations like height, length, etc.
I imagine that there is a commercial type antenna out there (probably a vertical) that fits your needs but it won't be cheap. if all you want to do is monitor the way to go is a long wire or random wire. cheap, easy, and you can always play with something new later.
