http://cgi.aol.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2217308727&category=3638

Might this be a 110V line noise filter?

Anthony

I imagine that it is, as the seller speculates, an antenna of some sort. The old-time MW (AM) loop antennas were called wavemagnets. To be on the safe side, though, I'd check for 110 VAC on those red wires before I hooked it to the front end of a TV or radio :-)

Yep...he's right. Those so-called devices were popular in the pre-cable days. Most were advertised that they would "turn your entire house (wiring) into a huge antenna!". Even Rat Shack sold things like this up thru the 80's. :rolleyes:

I recall those antenna things being sold on TV back in the late 60's thru the mid 70's. They had a cylindrical tube on top of the wall plug. They had been blamed for starting fires and the later versions had one plastic prong instead of 2 metal ones. Did any of these actually work?


Think of all the cheap bastards who probably tried to connect their TV's antenna terminals directly to the wall socket!

Anthony

Very poorly. House wiring is not conducive to TV reception. If memory serves me correct, peak reception would have been on Channel 8, which the TV audio is near the FM band. I haven't any idea what was inside these *wonder box antennas*. I have a feeling very little. :no:

It is probably just a small capacitor that couples the TV antenna lead to the power line, like the "built-in" antenna in FM radios. You can get the same capacitive effect by wrapping wire connected to the antenna terminals around the outside of the power cord.

I still see ads for those "Turn Your House Into a Giant Antenna" in various catalogs or checkout tabliods. I lump them in with those improve reception "balls" you attach to the top of your car antenna. Just flush your dough down the john, it's faster.:rolleyes:

I wouldn't waste my money on any of those plug-in TV antennas. They don't work well and could damage your TV, as the only thing standing between the wall plug and the twinlead or coax that connects to the VHF antenna terminals is a coupling network, consisting of little more than a capacitor or two. If the capacitor shorts, look out for fireworks, as another poster to this thread noted. (That cylinder atop the wall plug on some of the older units is there just for show; there's nothing much in there except the coupling network.)

If you are in a very strong signal area these antenna jigs might work (for black and white; I wouldn't think of using one on a color set, even if I lived within spitting distance of the stations), but don't expect miracles in the suburbs, let alone fringe areas. I live in a small town right at the edge of the coverage areas of all seven Cleveland TV stations, and wouldn't think of using such a poor excuse for an antenna on my set (it wouldn't work very well, anyhow; rabbit ears or even standard outdoor antennas don't work well here either, which is why almost everyone here has cable). The fantastic claims being made for these plug-in TV antennas (great reception "better than cable", etc.) are only high-pressure advertising ploys. The units themselves are almost always disappointments in real-world use.

BTW, Zenith used the term "Wavemagnet" in connection with its detachable loop antennas for their old Trans-Oceanic 3-way (battery/AC-DC) AM/SW portables. The label was also applied to the antennas used with the company's late-1940s-early-1950s table and portable radios; but again, this was just an advertising term, as the antenna itself was nothing more than a conventional wire-loop type mounted to the back of the receiver. IMO, they didn't work any better or worse than any other manufacturers' radios that used the same type of antenna. In fact, many if not most sets which used the pancake-loop antenna also had external antenna terminals, to which a long-wire broadcast antenna could be connected in fringe areas. These external terminals on AC/DC sets were booby traps for the unwary, however, as they often carried the full line voltage (depending entirely on which way the AC plug was inserted in the wall socket). Many unsuspecting people were severely shocked or killed when they touched the external antenna terminal and ground at the same time, and the plug was in the socket in such a way that the hot side of the AC line was connected directly to the chassis. This often happened with AC/DC radios used in bathrooms, although the fuse or circuit breaker on that circuit ordinarily kicked out as soon as the chassis touched ground, either directly or through the very low resistance of a wet human body. (In this day and age of GFCI outlets, which are required in all bathrooms, kitchens, laundry rooms, etc. in new homes, however, the protection circuit would swing into action and open the circuit immediately upon detecting such a short.)

I was not aware that some of these gutless-wonder plugin TV antenna gizmos had only one metal prong (the other being plastic) on their AC plugs. How on earth did they work if they were connected to only one side of the line?

To heathkit tv: Anthony, there are people in this world who are just that naive (or stupid) to go ahead and connect their TV sets' antenna terminals directly to the AC line, without benefit of a coupling capacitor or anything else. These folks learn the errors of their ways in a hurry when one of two things inevitably happens: the TV shorts out, catches fire and burns the house down, or, if they are lucky, all that happens is the front end of the set is so severely damaged that the set must be junked. Unfortunately, however, if someone connects a TV's antenna terminals directly to the line, it will almost always cause an explosion and/or start a fire inside the set, whether or not the TV is plugged in and/or powered on.

I have a 57 Zenith portable with a "Wavemagnet" built in.
It's an antenna mounted inside the (metal) cabinet, the switch just tunes it via different capacitors for best reception, just like the multi position switch on any number of aftermarket rabbit ears.

Oh well, it's still a cool name :D

I have no idea what the Zenith "Wavemagnet" TV accessory being auctioned off on ebay is :dunno: ; 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 :dunno:, 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.

Was just speaking with King Kullen, leader of the Atomic Mole People from the planet Zantac and he suggests that I test the unit by standing in a half full bathtub and connecting one lead of the device to my genitals and hold the other wire on my tongue.

If my toupee and glasses shoot across the room then I should reconsider hooking it up to the antenna terminals.

Seems like sound advice, dontcha think?

Anthony

Kinky!:D