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Sometimes
The Best Antenna |
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In the March issue of Popular Communications Ken Reiss had a wonderful article in his “Overheard” column called “Preamps, Attenuators, Filters, And Other Things That Can Cause Problems” (pages 44 through 49). In it he explained why some of the scanners we use today have the problems they do and why some of the things we think we need are just about the worst things to help fix those problems. One of the last things Ken wrote in that piece was, “You can do a lot with just antennas, which is the place where you should probably start.” This article is going to start right there, with antennas. While this won’t be a definitive article on all antennas and all wideband receivers (WBRXs), it will look at some things that I’ve tried and the results I’ve gotten. It should give you some ideas as well, and if so, I hope to hear from you. I’ve tried a number of different antennas with the Alinco DJ-X10 and I’ve noticed a very interesting thing: sometimes, the best antenna is not always the best antenna. If this is true, just what is the “best” antenna? First, we need a working definition of the “best” antenna. A radio operator—a CBer or ham—often thinks that the best antenna is one that is resonant at the frequency of interest and has an impedance of 50 ohms. Often, if not always, these are contradictory requirements, and you will hear arguments on the air about it from time to time. But, in general, for these services a resonant antenna is definitely within the realm of the best antenna. To an SWL (a shortwave radio listener), perhaps one definition of the best antenna is one that receives all desired frequencies equally well from all directions. I’ll try to clarify just what some of today’s wideband receivers require as an antenna and just what makes the best antenna. Sometimes having it all is not the best we can have and, in fact, can often be just about the worst with today’s WBRXs. |
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