Such small loops have worked very well. However, they are becoming more and more difficult to use indoors than ever before. Some of the most difficult QRN/QRM sources are right in our homes and their number increases every year. (I'm typing this message on one of the most prolific QRN sources today, but your refrigerator, washing machine, furnace and even many lights are just a few examples of others we have in our homes.)
While a loop can be oriented so as to put a source of interference in a null (assuming the desired signal is not in the same direction), all too often our homes have multiple sources of QRN or the QRN is being propagated along the house wiring so it is, indeed, coming from all directions at once if the antenna is inside or near the house. Before investing a significant amount of money in any indoor antenna, it might be worthwhile to string up a simple loop on, say, a wall, using a few push-pins. For a smaller test antenna, wrap a number of turns of hook up wire around a large cardboard square or circle. You can tape it in place near the periphery of a disk cut from a box. Hook one lead to the center pin of the antenna connector and the other to the chassis. It's not necessary to resonate the loop, but you can if you have a variable cap about. Put it across in series with the loop and adjust the turns to get a peak across the most interesting frequencies. Resonance provides some gain but gain is not an issue with a decent receiver. You can hear all that you'll ever hear as long as the QRN level rises when you connect the antenna to the rig. Compare that to even a modest outdoor antenna and see if you like the results. If not, you'll not likely be happy with the performance of a more expensive indoor antenna. And if you do like the results from the indoor antenna, you may find no significant advantage to using the expensive one, Hi! So why would anyone buy such a loop? Lots of reasons - here's a few: 1) They cannot put up any sort of outdoor antenna. A poor antenna is always superior to no antenna at all. 2) They live in a frame or other non-metallic building with few or no electrical devices inside. 3) They *must* have a tiny, compact antenna to fit in their space or provide the portability required. 4) It looks "right". (Don't laugh. A lot of expensive stuff is purchased because it "looks right" regardless of performance - or lack thereof: everything from homes, cars, boats and aircraft to Ham rigs.) Ron AC7AC -----Original Message----- Hi Ted, Out of curiosity, what broadband antenna are you planning on using? I am thinking about purchasing the AOR LA390. It's a bit on the expensive side, but from its design, should work well. Here's a link: http://www.aorja.com/pdf/LA390.pdf Do a search for AOR LA390, and you'll find the US based retailer for this antenna. 73, James KC2UEE ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
