So while at a local thrift store yesterday, I came across something similar to the picture I've attached to this post. It was only (as they'd say on The Price Is Right) ONE DOLLAR, so I got it! I brought it home, attached the dual leads to my TH2's indoor/non tuner antenna hole, and it performed just as good as the single wire stock antenna or any of my homebrew single wire antennas that are about as long or a little shorter than the stock antenna. Altogether that loop wire can't be more than 7 or 8 feet, making it Part 15 legal. What I want to know is, why didn't i.A.M. or ISS or any of the other previous makers of the Talking House use a loop instead of the straight wire? The loop just makes things a little more easier in my opinion.
I'll bet if you had a manual ATU you may even do better. I've ofte wondered what would happen if you done just that. Now if you were to have one at the end of an ATU and stuck that outside I wonder if your range would greatly exceed 600 Ft the range most get with the Talking House transmitter on the wire?
Seems better than a long 10ft wire if using indoors with AM. More compact and most rooms aren't near 10 ft high to get the long wire verticle.
Guess it would work with any AM transmitter?
Wonder if those tunable loops like this.... 
, could work to as it's tuned for the AM frequencies.
The tuned, loop antenna shown in the picture attached to the opening post is designed to improve the reception of a receiver. The receiver is positioned near the loop so that its internal antenna can couple to the nearby fields produced by the loop.
Such a loop antenna is not an efficient radiator. For operation under FCC §15.219, a correctly driven, 3-meter-long, linear conductor produces much more radiation than that loop (other things equal).
Thing with a loop antenna for transmitting (and a benefit for using it for receiving) it they are VERY directional. So you'll find increased radiation in two directions with nearly zero radiation in the two directions at 90 degrees. The same benefits of being able to null out noise and interference when listening also happen when transmitting. So while some listeners may get increased signal, it will be at the loss of signal in other directions.
TIB
From Reply 5: ... So while some listeners may get increased signal, it will be at the loss of signal in other directions.
Radiation from that loop will be directional, as stated in Reply 5.
However the r-f power radiated by that small loop even in its directions of maximum gain will be greatly reduced from the power radiated in all horizontal directons by a correctly-driven, 3-meter, vertical, linear conductor (other things equal).
Here is a sort of carrier current or should I say a carrier alongside the power line question I have to ask. OK lets way your Land Lord would not allow you to put up an outside antenna and you were to use that loop and your electrical box is near the loop. What would happen if you were to point that loop right at the box so as all of the radiation would emit towards the electrical box? Would that sort of act like a very crude carrier current coupler if your power lines were above ground thus making your transmitter sort of a grey area part 15:219 and part 15:221 device at the same time?
If so what would the FCC think about that if your loop was not over the 3 meter antenna rule?
Tim says: "Thing with a loop antenna for transmitting is they are VERY directional."
There may be a way of benefitting from the directionality of a loop for AM transmission.
Starting with the fact that using a plain vertical antenna radiating in full 360-degrees wastes MOST of the precious field strength into empty air, it might be desirable to FOCUS the energy DIRECTLY TOWARD a particular house or populated section of the surrounding area.
MOREOVER, it would become (perhaps) possible to place a second or even third transmitter/loop-antenna inside the NULL of the first transmitter(s), aimed at other buildings in other directions, USING THE SAME FREQUENCY.
Hmmm?
Worth an experiment, I suggest.
1. The only parts of the radiation pattern of a small vertical loop used for MW transmitting/receiving having any useful "focus" are its two nulls lying ±90° from the plane of the loop.
2. The peak gain of that loop lies in the plane of the loop, but for a §15.219-compliant system its maximum radiation in all directions will be much less than from a 3-m vertical monopole (other things equal).
Following on Rich's "Focus" comments, yes, that's the way I visualized it, and the reason why I think my idea might be a slightly more effective way of reaching particular zones rather than wasting most of the energy going nowhere.
After I do a study course in designing loops, I will add this kind of experiment to my antenna projects already on the "to do" list.
Earlier: "I think my idea might be a slightly more effective way of reaching particular zones rather than wasting most of the energy going nowhere."
Below is a comparison of the radiation patterns and relative gains of a loop antenna having a circumference of 3 meters with a §15.219-compliant, vertical monopole. The same amount of r-f power was applied to the feedpoints of those two antenna system configurations.
Conclusion: Other things equal, the "zones" reached by the directional loop would include much _less_ geographic area than produced by the 3 meter monopole.
Looks like the loop has no "throw"... that's a bummer.