|Home | Articles | Forum | Glossary | Books|
Two recommendations: A poor man's indoor rotary FM antenna and a rational audiophile publication.
by LARRY KLEIN
Once upon a time, if you bought an FM tuner or receiver-and took the trouble to read its instruction manual-you would always be warned that if you wanted really good reception a rotary roof-mounted antenna was the only way to go. Obviously, the manual writers were not living in the heart of New York City, where getting the landlord's permission to mount a roof antenna without a rent increase was as difficult as climbing Mount Everest.
In truth, I found that the FM reception situation, at least in Manhattan, was nowhere near as bad as the tuner manuals (and hi-fi magazines) would have you believe. True, certain steel-frame buildings effectively blocked the FM signal in certain locations, and most tuners were no paragons of sensitivity. But if you carefully repositioned your 300-ohm folded dipole flat-line antenna for each station, good-to-adequate reception could be achieved for most stations.
Long before the idea was generally accepted, I thought of using a TV rabbit-ear antenna for FM. In fact, I commissioned the late Herb Friedman to test a dozen or so rabbit ears for FM use and write up the results. As I remember the article, Herb's conclusion was that the more complicated antennas worked no better than the simpler ones.
And so it went for several years until I installed the PMIRA, a poor man's indoor rotary FM antenna in my system. It consists of a two-pole, three-position (or more) switch (rotary, slide, or lever type), and three (or more) flat-line folded dipole antennas of the kind normally supplied with tuners and receivers.
The antennas are mounted with two of them at right angles to each other and the third is placed diagonally with respect to the others. For best results, the antennas should be separated to avoid interaction. At FM frequencies, the capacitances between the switch terminals are low enough to be insignificant.
If you don't want to construct your own FM folded dipole, Radio Shack has one listed for $3 on page 105 of its 1993 catalog. A $1.39 two-pole, six-position rotary switch is on page 113. You don't have to use all six positions, of course, but you could try fine-tuning a dipole for your favorite station at one of the extra switch positions.
How well does the antenna work? Fortunately, I own an excellent 15-year-old tuner (the Micro /CPU100) that will provide a direct reading of relative multipath strength and the antenna signal input. The meters on the tuner leave no doubt about the effectiveness of the PMIRA. As I tune through the thirty-odd stations whose call letters are programmed into the tuner's memory, I can see the signal strength and multipath (if any) vary for each. Resetting the switch for optimum signal input and minimal multipath for each station takes but a moment. On some stations, the setting that provides maximum signal strength is not the same as the one that provides minimum multipath. At other times, the meter readings are good, but a different switch setting reduces the background hiss level.
I've used the PMIRA for about 15 years, first in midtown Manhattan and later in the suburbs 30 miles away, and I can attest to its effectiveness in both locations.
If you are using an indoor FM antenna, then 25 feet of 300-ohm flat TV cable converted to folded dipoles and a $1.39 rotary switch will make a substantial improvement in your FM reception.
A thinking audiophile's magazine Regular readers of this column should by now be aware of my somewhat jaundiced attitude toward pricey high-end audio equipment. However, I reserve my real annoyance for those audiophile magazines (and their writers) that with a witch's brew of pseudo-science and unabashed subjectivism, tout such equipment to their faithful followers. I'm referring, of course, to magazines such as Stereophile, The Absolute Sound, and several others with limited circulation, that keep their readers abreast of the latest audio excesses.
All is not lost in the Twilight Zone, however. There is a countervailing force among audiophile magazines that I've not previously mentioned on these pages. I'm referring to The Audio Critic, an approximately quarterly publication that, if taken regularly, is an effective antidote to the self-serving silliness of the other audio-buff publications. The Audio Critic's editorial attitude-and prose style-is illustrated neatly in a recent piece by its editor, Peter Aczel. He feels that accountability is a major problem among the esoteric audio journals. Subjective reviewers regularly assert that they hear (in a given piece of preferred equipment) improved sound staging, front –to-back depth, width, greater transient definition, and sometimes even improved rhythm and pace. (As to the latter, we know that tape recorders and record players are sometimes off-speed-but amplifiers ?) Such judgments are seldom if ever backed up by any rigorous test procedures. Mind you, the supporting tests we rationalists call for are not of the equipment's electrical performance, but rather of the reviewer's ability to demonstrate objectively, with statistically valid double-blind listening tests, that he really hears what he claims he hears. Over the years, controlled tests-many of which I've written about in these pages-have consistently shown that the subjective reviewing that appears in Stereophile and The Absolute Sound is essentially unreliable, influenced as it is by price, fads, technical ignorance, and unfettered egos. That is not to say that some preferred piece of equipment might not be very good-if not particularly cost effective.
In contrast to those publications, The Audio Critic's reviews are models of rationality, coherence, and technical competence. Measurements from state –of-the-art test equipment are backed up by circuit analysis and evaluation of the construction and parts quality. When TAC's double-blind listening tests reveal an audible difference (and in a lot of electronic audio equipment there just isn't any to be heard), the electrical source of the difference is investigated and discussed. Mysteries are resolved rather than relished.
While equipment reviews are the core of TAC, the magazine also includes excellent in-depth survey articles exploring entire technologies (e.g., CD player design, low-bass reproduction and preamp circuitry). I say without embarrassment that I have learned a lot from them. Such articles are reinforced by no-holds-barred forums whose participants include the foremost names in audio, both academics and manufacturers. For me, the most fun-filled part of the publication is a column called "Hip Boots: Wading Through the Mire of Misinformation in the Audio Press." I'm pleased that editor Aczel has not seen fit to aim his acerbic pen at any of the columns I have written.
A subscription to The Audio Critic that includes four consecutive issues starting with the current one (No. 18) costs $24 in the U.S., Canada, or Mexico. For $5 extra, issues 16 and 17, chock full of good stuff, will also be sent along with your subscription. Write to The Audio Critic, Dept. RE, P.O. Box 978, Quakertown, PA 18951. You won't be disappointed!
Also see: DRAWING BOARD
|PREV.||NEXT||More E-N articles||HOME|