"After listening to another static-filled broadcast of A Prairie Home Companion -- sometimes it's difficult to tell how much static is part of the program -- I was inspired to try out the Pi-B indoor amplified AM/FM antenna. (It costs about $30) I had been using Terk's Tower antenna, which seemed to work about as well as a wire coat hanger--which is to say, not well at all.
"Although I live less than five miles from the broadcast towers that blast the entire Los Angeles basin from atop Mt. Wilson, radio reception at my home has always been problematical because it's right at the base of the mountain and it doesn't enjoy line-of-sight views of the towers.
"Like most Terk products, the black disc-shaped antenna with a purple-glowing power indicator is visually stunning; some folks would undoubtedly be proud to display it on their mantel. I don't care a whit about its aesthetics, however, as it lives hidden in my home theater cabinet. Call me shallow, but I just want an antenna that works.
"The Terk Pi-B did not disappoint. After making three connections--AM antenna, FM antenna, and AC power--and fiddling just a bit with the gain knob, I was pulling in stations I've never gotten before. My favorite stations (that is to say, the handful of stations I've been able to receive with only moderate static) come in crystal clear, and I can now clearly receive dozens more stations.
"In my case, I'll buy the Pi-B. Is it for you? I have no idea, and that's my biggest gripe with Terk. The company has a line of home radio antennas, but offers no clear way of identifying which works in a particular situation or which is better than another.
"Few clues can be found on the packaging, in the manuals (yes, the antenna has a 6-page leaflet, er, manual), and on the company website. Based on the vague description of the Tower, I thought it would work for me; it didn't, and turned out to be a waste of money. The Pi-B description is similar, yet in my situation the performance of the two antennas is dramatically different. If you buy a Terk antenna, be sure you can exchange it for a different model if your first choice doesn't work."
By IVAN BERGER; Ivan Berger is an editor at Audio magazine.
Published: Saturday, December 16, 1989
New York Times
You don't have to mount an antenna on the roof to get decent FM radio reception. Many indoor antennas cost much less than a directional roof antenna with a rotator, and provide much better reception than the antennas that come with most FM sets.
Even a $5 rabbit-ear antenna can help. The rabbit ear works exactly like the floppy dipole antennas of ribbon wire that come with most FM sets, but its stiffness and multiple adjustments let you aim it toward the clearest signals and reject ''multipath,'' the clusters of signal reflections (equivalent to TV ''ghosts'') that make the sound fuzzy and distorted. Magnum Dynalab's SR-100 Silver Ribbon is an elegant rabbit ear, albeit more expensive (under $30); in a New York City apartment, it did as well as several more expensive and elaborate antennas.
Most of the latest indoor models are designed to be inconspicuous. Parsec's Stealth ($45), a black box the size of a child's fist with a soda-straw sized mast, can hide behind a hi-fi cabinet. This is more for suburban than for city use: its built-in amplifier can beef up moderately distant signals, but it cannot screen out undesired signal reflections.
Terk's FM+ ($19.95) is visible, but inconspicuous. It's a thin plate about five inches square made to stand up or lie flat. Flat, it picks up signals from all directions, like the Stealth. Standing it is slightly better able to deal with mild multipath problems. Terk's $85 Pi#2 is similar, but includes a built-in amplifier that can be adjusted to strengthen weak signals or to tone down signals strong enough to overload an FM tuner.
Unlike the FM+ and Pi#2, Terk's FM 9300, a slim, tapering tower 17 inches tall, picks up signals from all directions when standing and, when on its side, focuses on stations it is pointed to. Its built-in amplifier can be adjusted to strengthen signals but not to weaken them. On its side, and pointed at the clearest signal, this $35 antenna screens out unwanted signals much better than the other Terks.
Audioprism's $49.95 Hi-Q 6500 is a flat box 9 by 9 by 2 1/4 inches. It is designed for FM listeners in large-city downtowns where there are many high buildings; there the problems include too many strong signals rather than weak ones. Its frequency selector knob helps it filter out interfering signals, while another knob tames signals that are strong enough to overload the tuner. Parsec's $150 Arc is a larger box, about the size of many FM tuners. It, too, has a frequency selector knob, but it can strengthen signals, which makes it better for surburban than for city use. Its frequency selection and amplification can also be used to improve AM reception (other models listed here are for FM only), as can a knob that aims the antenna's AM section and a switch that filters out some AM interference.
Also costing $150, Audioprism's Model 7500 is a pole four inches thick and seven feet tall set on a wood base. It has no amplifier, but its size gives it enough pulling power for suburban use. It is not directional, but Audioprism's shorter (five-foot), fatter (one-foot) APPA-8500 is. This antenna, $250, pulls signals even more strongly than the 7500, but also includes an attenuator for overstrong ones. It can be aimed by remote control, which is especially useful because FM signals in a room change as you move around, so the way you orient an indoor antenna when you're standing next to it might not yield the best sound when you're sitting in your chair.
Tests of all these models except the Audioprisms indicate that the best antennas for big-city use are directional models without amplification; the Magnum Dynalab Silver Ribbon worked especially well in Manhattan.
But the farther you are from the stations you want, the more signal-pulling power you need. Antennas that achieve this without amplification (like the bigger Audioprism models) yield slightly cleaner sound, but are bulkier and cost more.
Most of these antennas use round 75-ohm cables, which can be extended to about 20 feet without significant signal loss. That lets you move your antenna to a window, where it will pick up more and stronger signals.
The flat 300-ohm ribbon cables used by some antennas (including the Silver Ribbon and the FM+) cannot be extended without weakening the signal and picking up undesired signals and interference. Most FM sets have either 300-ohm screw terminals or 75-ohm threaded jacks, but not both. Antennas usually come with adapter transformers for proper mating to FM sets of either type.
Abstract: The purposes of this study (and subsequent efforts) are several: (1), to extend earlier models of the FM reception process, to include as much II "realism" – i.e., non-ideality of both the linear and nonlinear elements of the typical FM receiver – as possible, and still retain analytical and computational feasibility; (2), to examine explicit cases of interference produced by one or more deterministic signals; and (3), with such specific examples, both to provide insights into the distortion effects generated by the nonlinear interactions of the various (desired and undesired) signals in the receiver and to present the analytical framework of the instantaneous outputs required in any (subsequent) fully statistical treatment, where now the interference (e.g., "noise") is noticeably nongaussian. In addition, these deterministic models may also provide useful structures for simulation studies.
The instantaneous receiver outputs are obtained for the following receiver models, (A), and interference "scenarios", (B): for (A): (I) "superclippinq: and an ideal discriminator; (II), no limiting and ideal discriminator; III, "superclipping" and a non-ideal IV, no limiting and a non–ideal discriminator. For (B), with each (A), we consider explicitly the cases of: (i), one cochannel interfering signal; (ii), one adjacent channel interferer, and (iii), M symmetrical interferers (M = 1, 5). Also included are the mean and mean-square outputs. All the above are obtained here for idealized (i.e. sufficiently wide-band) RF-IF receiver stages, which are essentially linear under this condition. The results are illustrated with cases for selected, typical parameters of the combination of the interference-receiver structure. For other combinations, the appropriate computer programs are included in the Appendix.
Very expensive antenna for what they offer. It looks well made.
It's shunt feed dipole. Probably a capacitor in the box.
I like their eave mount but it's to pricy also for my taste.
However if their indoor balun looks interesting until you realize it's not possible to build one that is zero db loss if it transforms impedance. So I am not sure between their prices and zero db balun if they are on the level.
On July 6, Prometheus filed comments with the FCC to oppose a proposed power increase for digital radio signals (aka "HD radio"). But since most people haven't heard enough about digital radio to even weigh in on the issue, this month we've put together our Top Ten Problems with Digital Radio.
The Prometheus Radio Project, a non-profit organization founded by a small group of radio activists in 1998, builds, supports, and advocates for community radio stations. Primary the goals of the organization are to "demystify technologies, the political process that governs access to our media system, and the effects of media on our lives and our communities." Unfortunately, its effort to demystify the technology is not always accurate.
For example, the group recently posted a document titled Top Ten Problems with HD Radio. This document attempts to show the flaws with the HD Radio system, however, there are flaws in the Prometheus logic and science.
This references the Prometheus article. While portions are copied here, the complete text is available at the link. The Prometheus questions are included, but only part of the Prometheus answer may appear.
NPR Labs Interim Allowable IBOC Transmission Power Calculator Published
To illustrate a simple and effective procedure for determining the allowable increase in IBOC power, NPR Labs has developed a set of procedures for Reserved Band and Non-Reserved Band stations, based on the FCC’s standard allocation techniques. While allowable power can be calculated by any engineer using tools available on the FCC’s web site for calculating distances, bearing, and field strength, NPR Labs, with computer processing and assistance from Cavell Mertz & Associates, Inc., has performed the calculations for all licensed stations in the U.S. and made them accessible through the lookup tools on this page.
Click here to run the lookup tools and read the specifics.
NPR Labs PAD Applications incompatible with iBiquity v3 Importer software
NPR Labs has learned that the PAD applications provided free-of-charge to NPR Members are incompatible with iBiquity's version 3 Importer Software. NPR Labs is working with iBiquity to resolve the incompatibility and will publish revised PAD applications as soon as practicable.
Announced at the 2008 Public Radio Engineering Conference, the NPR Labs Online Viewing Application (or NOVA) is a Google Maps mashup that lets users dynamically explore mapping and demographic data for PTFP-qualified transmitters.
The tool is now freely available for viewing, and is intended for anyone affiliated with a PTFP-qualified transmitter.
New Accessible Radio Publications
Click here To browse Radio Text Display Final Report: 3 Studies, Best Manufacturing Recommendations For Blind and Low Vision Users, Results from NPR Election Night '08 Captioned Radio Event, and see the NPR Labs' CONSOLIDATED REQUESTS FOR INFORMATION (RFI)
Digital Radio Coverage and Interference Analysis Study Now Available
NPR Labs has completed their DRCIA project - a monumental 18-month study projecting the consequences of interference between HD Radio and station analog broadcast signals, as well as HD Radio’s overall success in meeting coverage expectations and needs. Visit http://www.nprlabs.org/research/drcia to download the final report.
It's too ingrained already to go away. Probably the one point is if channel 5 and 6 were to be vacated and radio grab that 12 MHz, then digital only stations could be licensed there. As many bad things as I can say about IBOC, it's not going away soon. Someday, sure, NTSC is all but gone. Mono is gone. While not a lot of people have IBOC receivers the number is increasing. I really don't know the danger of a 10 db increase of the digital subbands, but 10 db adds a lot of fade margin and range. Stereo FM came along, the difference channel was plagued with noise, and few receivers were Stereo. Then AM Stereo, and few stations were stereo, only a couple of radios. Then it was more common. Color TV sub carrier put herringbone on BW TVs. Then they had traps for the 3.58 MHz carrier.
Some of the newest FM tuners are better than anything we have ever been able to buy, and in the presence of digital with digital built it also to add to the value.
Could they have done better, oh yes no doubt. Is IBOC doomed? I doubt it. As soon as the car radios at Wal-mart and new cars all have them, people will listen to it.