I have no idea what the Zenith "Wavemagnet" TV accessory being auctioned off on ebay is
; in fact, I've never seen anything like it in 35-odd years of working with TV, radio and electronics in general. The description states that the unit has an AC outlet into which one plugs the TV power cord, a 110-volt AC cord of its own, and the two leads which supposedly connect to the TV's antenna terminals, so I'm guessing it must be some sort of gizmo to connect the TV's antenna terminals to the AC line, utilizing said power wiring as a giant television antenna (later devices did the same thing without having to plug the TV power cord into it). The fact that the box has its own AC line cord leads me to believe there might be an amplifier inside it, tunable via the three-position switch on the front of the unit; that or else the switch was used to turn the TV on and off via a relay (I arrived at that conclusion after seeing the AC socket on the box). However, if this were an amplifier or a unit meant to switch the TV on and off along with the amp functions, would there not be an "off" position on that front-panel switch? The switch on the unit only has three positions I can see: A, B and C. If there is an "off" position, which I doubt
, Zenith has it pretty well hidden.
The only other thing I can come up with is that this may have been some sort of early TV booster, although if this were so, there would be (would there not?) a pair of terminals to which the VHF antenna would connect, not to mention a fine-tuning control to adjust the unit for the channel being viewed at the time.
I doubt that this unit was any kind of super TV antenna. Back when this unit would have been new (1950s-early '60s), the idea of using the line cord, let alone the home's power wiring, as a television antenna probably hadn't been explored yet (even though some radios used the line cord as an FM antenna by way of a capacitance-coupling unit by the late '50s, as one of my Zeniths does). Even if it had, the dodge would have failed miserably in most reception areas (certainly fringe areas), because television stations (VHF only in the '50s in most areas) operated at much lower power than today's super-power UHF stations. Most homes in the '50s and early '60s, located any distance from the stations, had large conical VHF-only antennas; some of these installations had separate antennas for high and low band stations. Since most people had b&w TV in the '50s through the '70s or thereabouts (and most cities at that time did not have UHF stations yet), these antennas worked well for VHF reception. No one back then, I don't think anyhow, would have ever dreamed of using their television's line cord as an antenna, although many sets did have built-in antennas inside their cabinets (I once had an early-1950s Capehart console which had a rotating antenna mounted in the top of the cabinet; it was adjusted by turning the part of the wheel which protruded from the back of the set). Zenith had a variation of this scheme, as did many other TV makers; however, none of the major manufacturers, to the best of my knowledge and belief, ever designed their TVs to use the AC line cord as an antenna until those gutless-wonder adapters under discussion in this thread came out in the '60s. As I stated in a previous post, these gizmos are come-ons for the most part; the uniquely-designed cases (the one with the cylinder above the AC plug comes to mind as I write this, although I'm sure there were other equally worthless designs) are probably what brought in the money for these manufacturers (these antennas were more than likely off-shore products, imported from Japan and made by companies like Fedtro, et al).
The problem with these gizmos, as another poster accurately noted here, is, plain and simple, that they don't work well unless you are practically surrounded by TV towers, and even then you can't get reception even approaching that from a good outdoor antenna or cable. The reason, again as noted in a previous post, is that power wiring in buildings makes a very poor, bordering on useless, television antenna in local or suburban areas. As for fringe areas, forget it. These plug-in things won't work at all if you must have a tower-mounted (or at least an amplified rooftop) antenna to get decent reception in your area.
I've never owned or used any of these gutless-wonder "antennas" in all my years of experimenting with electronics, radio and TV, and I wouldn't have one today if they could still be bought new (I certainly wouldn't waste my money on a used one either).
As for the Zenith mystery box now up for auction on ebay, I wish the seller luck in unloading it. I honestly do not believe anyone other than a collector of early TV accessories, equipment, etc. would want it, as no one here on this AK forum, myself included, seems to have any idea what this thing is or what it does. Someone mentioned checking with a voltmeter across the leads which supposedly connect to the TV's antenna terminals, with the cord plugged into an AC outlet of course, before trying to use the box; this is an excellent idea. I would not dream of hooking up a mystery unit like this to either of my TV sets without knowing, beyond the shadow of even the most unreasonable doubt, what the box is supposed to do or not do for my TV reception. I'd do the voltage test first. If there were any voltage at all across those leads (or from either wire to ground), I wouldn't bother connecting the thing to my TV. My set's extended warranty doesn't cover damage from unknown devices or sources.