FM RECEPTION TIPS
By Jim Perry, Greater Philadelphia Radio Group
(with help and print references from Marc Wielage, CompuServe CEAudio Forum)
E-Mail to Jim
Every radio and TV station has areas of
less-than-wonderful reception. Most of these areas are not a result of a technical
deficiency at the station; rather, local topography, including hills, buildings, trees,
etc., is usually the culprit. A special case for classical stations is that they tend to
adjust their audio for a more "natural" sound, as opposed to more
"aggressive" stations which adjust their sound to be as loud as possible at all
times. The natural sound of classical music tends to reveal every little reception flaw,
while the audio of loud stations masks many ills.
Optimizing reception therefore becomes paramount when
listening to classical music. These tips are designed to help you identify the cause of
reception problems, choose solutions, and, finally, enjoy great music, regardless of
Multipath: Static, noisy, distorted stereo
sound, especially when music is playing, that greatly improves when switched to mono.
Multipath is the most common source of problems, and is caused by signal reflections from
buildings, mountains, trees, etc., just like the "ghosts" in TV reception
(before cable). Multipath can occur even in strong signal areas.
Weak Signal: A relatively clear but
"hissy" stereo sound, perhaps with some slow fading. The hiss is nearly
eliminated when switched to mono.
Strong local station: Pieces of another
station's sound splattering over the desired station.
Local interference: Interference from other
sources such as two-way radios, Citizens' Band operators, and static buzz from appliances
and power poles.
-- or any combination! [Back to Index]
Your Chances of Success
Predicting local FM reception quality is far from an
exact science. Before spending money on elaborate equipment and antennas, a certain amount
of experimentation would be prudent. It can be particularly disheartening to spend time
and money on a fancy new radio, only to find no real improvement.
To help predict your chances of success, try the
following: carry a good, trusted portable radio (with its telescoping antenna fully
extended) from room to room, listening to the station of interest. If you can get at least
a fuzzy, but listenable signal in any room, chances are good that a rooftop antenna (or
even a good indoor antenna) may yield very good results. Or, if you can get the station on
your car radio while in the driveway or garage, this is also a good omen. If, on the other
hand, you get nearly no reception at all no matter what you try, proceed with caution; a
fancy new antenna may be an expensive, but futile, experiment.
Careful tuning and listening are important in
determining the type of reception problem you have:
- Do you almost always hear the desired station, but
it's distorted much of the time? Does the audio improve markedly when the receiver is
switched to "mono"? This is a classic description of multipath (see definition
above). Experimentation with a "positionable" indoor antenna may cure this
problem. Severe multipath may be minimized by a carefully aimed outdoor antenna. Some
newer receivers have features that help in reducing the effects of multipath.
- When the desired station fades, does another
(unwanted) station take its place, or is the channel empty (except for normal
"static" and distant weak signals)? If another station on the same channel is
coming in almost as strongly as the desired station, your receiver-antenna combination may
be having trouble choosing one over the other. A directional outdoor antenna, pointed
toward the desired station (and away from the other station) may help.
- Is an unwanted station (or "pieces" of its
program) interfering much of the time? A strong station on a nearby channel may be
"splattering" onto the desired station. As above, a directional antenna pointed
at the desired station may help. A good-quality receiver may be the answer as well; check
out the "narrow band" feature of better receivers described below.[Back to Index]
Things To Try
The following suggestions are in a decreasing
order of preference. And, as you might expect, the more involved solutions are generally
near the top of the list. An exception is buying a new receiver; in most cases, this
expensive option is a last resort. [Back to Index]
The almost universal solution to reception problems
is a directional outdoor antenna. This antenna, called a "yagi," looks just like
a plain TV antenna. There are dozens of different models available in the $25 to $250
price range. Important: this suggestion assumes that the radio you're using has
connections for an external antenna (many table radios and most portables do not
have such connections). Be sure to check the radio first. Some antenna sources:
P.O. Box 1416 Industrial Park Drive
Smithfield, NC 27577
3000 Kirkwood St.
Burlington, IO 52601
And what may very well be the best FM yagi (used by
many broadcasters to solve difficult reception problems), the venerable APS-14, available
Antenna Performance Specialists (APS)
Bolton, CT 06043
E-Mail to Ed Hanlon at APS
In every case, use well-shielded coaxial cable
(usually labeled "CATV" or "RG-6) from the antenna to your radio, using
appropriate static drains and grounding ("coaxial lightning arrestors") where
the antenna's cable enters the house. Lightning arrestors are available from some of the
above antenna companies, as well as a full line of high-quality models from:
Electronics Manufacturing, Inc.
E-Mail to Larry Cagle at EMI
Properly installed connectors are very important; buy
the best and install them with care. Although flat twin-lead is theoretically less noisy
than coaxial cable, the performance difference is negligible for most home installations.
If you have a quantity of twin-lead on hand, give it a try, but the potential benefits of
coaxial cable's shielding and ease of installation make it the cable of choice.
You can often get better results by using an
inexpensive outdoor antenna with an inexpensive radio than you can by using a fancy indoor
antenna with an expensive radio. A well-installed and well-maintained outdoor directional
antenna alone can have a dramatic and unmistakably positive effect on FM reception, even
with inexpensive or older receivers.
Directional Antenna Considerations:
If an outdoor antenna doesn't work to your
satisfaction, it's very difficult to disassemble and repack for return and refund. Some
stores may not allow such an antenna to be returned, except for manufacturing defects. In
any event, your time and money spent on installation is not recoverable.
If you only listen to one station, or to several
stations from the same direction, you can leave the antenna aimed in that direction for
best reception. However, if you listen to stations from different directions, you may want
to consider an antenna rotor (rotator) to re-orient the roof antenna's position. Before
buying a rotor, however, it may be wise to manually optimize the antenna's position for
your favorite station, then listen to the other stations. They may come in fine with that
particular orientation. If not, good rotors are available from Jerrold, Winegard, and
For more information on complex antenna
installations, read Michael Salvati's excellent series of articles on FM antennas in the
January, February, March, and April '78 and the January '79 issue of AUDIO magazine
(available in any large library). Also good are Len Feldman's antenna comparison in the
January '83 issue of AUDIO and Julian Hirsch's article in the May '85 issue of STEREO
REVIEW.[Back to Index]
Non-directional (omnidirectional) outdoor antennas,
such as "turnstiles" and "S-shaped" may be helpful in many instances,
and usually give better results than any type of indoor antenna. But if eliminating
multipath and/or interfering stations is the goal, a non-directional antenna may not help.
Only directional antennas can attenuate contaminating signals from other directions, such
as reflections from nearby hills or buildings, or an adjacent- or same-channel interfering
station. [Back to Index]
Indoor antennas generally do not work as well as
rooftop/attic antennas. In most cases, a very inexpensive rooftop/attic antenna will
outperform even the best indoor antenna. Again, experimentation is paramount. After
connecting the indoor antenna to your radio, try moving the antenna anywhere its leadwire
will allow for best reception. In tough indoor reception areas, it's important to move the
antenna and, if necessary, the receiver, around the room or house, searching for a good
signal spot. Try anything from a $10 set of plain "rabbit ears" from Radio
Shack, to what many critics say is the best indoor model, the $200 Audio
Prism APPA-8500, made by:
2729 152nd Avenue NE
Redmond, Washington 98052
Tel. (425) 869-8482; Fax (425) 869-1873
Contact: Byron Collett at firstname.lastname@example.org
A visit to a high-end audio store will generally
yield at least one or two fancy indoor FM antennas (along with a lot of strong opinions on
just about everything to do with FM).
Often, it's very difficult to pick up desired
stations inside an office building. The villains here are usually the metal-frame building
(which can shield the signals and prevent them from reaching your indoor antenna),
fluorescent lighting fixtures (which often produce broad-spectrum electronic noise), and
interference-producing devices like computers and other office equipment. In some cases,
locating a set of rabbit ears against an outside window can improve office reception. As
above, it's important to try the antenna and radio in several locations around the office,
sniffing out good signal areas.
Important: One positive thing about indoor
antennas is that they're easy to pack up and return to the store if they don't perform. Be
sure to determine the store's return policy before you purchase any antenna.[Back to Index]
A Better Receiver
Buying a better radio, receiver, or tuner may be the
most expensive route to reception nirvana, and should be considered only if your antenna
efforts yielded unsatisfactory results. And there's still no guarantee that a new radio
will solve certain reception problems, so determine your return/refund rights before
you purchase. Talk to the equipment salesperson about your reception problem to establish
in advance why you're considering a new receiver.
A current-model receiver may only marginally improve
reception, but may have other features, such as station pre-sets and digital tuning, which
will aid in finding your favorite stations. Many "reception" problems turn out
to be mechanical tuning difficulties with a hard-to-read or poorly calibrated dial, a
problem quickly solved by a radio with digital tuning.
Important radio technical specifications to look for
- Alternate-Channel & Adjacent Channel
Selectivity: this refers to the ability to separate stations close to each other in
frequency. Higher numbers indicate better performance.
- Usable Sensitivity: the minimum signal strength
needed to provide a quiet, undistorted audio (the lower the number of microvolts or
femtowatts the better).
- Capture Ratio: the radio's ability to select
one station over another, based on the difference in their strength; the lower the number,
- AM Rejection: doesn't refer to getting rid of
AM stations!; rather, this specifies how successfully the radio ignores noise-producing
level variations (static, sputtering, etc.) in the incoming signal. The higher this
number, the better.
- Image Rejection: refers to the radio's ability
to suppress internally generated spurious noises and squeals, especially in the presence
of strong signals or signals of certain frequencies; the higher the better.
Most modern radios have respectable stereo separation
and frequency response, as well as low residual noise and distortion. The real
tests are the specifications listed above; these will make the most difference in
difficult reception situations. Many better receivers have other features that may help in
poor signal situations; see Compromises below. [Back to Index]
If the basic signal is weak, but otherwise free of
multipath distortion and interference, you can sometimes benefit by the use of an RF
(Radio Frequency) amplifier in the antenna line. If you live anywhere near a radio or TV
station, however, there's a strong possibility that the station may overload the antenna
amplifier, causing more problems.
As always, start by trying an inexpensive amplifier,
and bring it back if it doesn't help. Considered one of the best is the model 205
"Signal Sleuth" Tunable FM Signal Amplifier from Magnum Dynalab at:
Magnum Dynalab Corp.
8 Strathearn Ave # 9,
Brampton, Ont. L6T 4L9
Tel: 800-551-4130 Fax: 905 -791-5583
Magnum also offers a free booklet on FM reception for
audiophiles called "Rediscover FM Stereo," and is highly recommended.
[Back to Index]
Of course, our goal is crystal-clear stereo
reception, but if you can't receive the station cleanly in stereo, switch the tuner or
receiver to its mono mode. Often, just switching to mono will substantially reduce noise,
static, and multipath distortion.
The best radios provide "narrow I.F.
bandwidth" modes, which can effectively notch out nearby interfering stations on the
dial. While these modes tend to increase distortion slightly, they can often make a noisy
distant station completely listenable.
"High-Blend" is another common feature.
This circuit helps multipath and weak signal situations by decreasing the high audio
frequencies (where most of the noise is) and by reducing stereo separation.
Sometimes one or several of the above special modes
in combination with each other can make a dramatic reception improvement. [Back to Index]
If you're experiencing local interference problems
(static, hiss, crackling, pops, noise, etc.), and are fairly sure it's not multipath, try
to find the interference source. Possibilities: arcing high-tension power lines, poorly
grounded motors, appliances, spark plugs from passing cars, etc.
In these instances, there is no substitute for an
experienced ear. If you know someone with electronics expertise, perhaps a local amateur
radio operator, try to arrange a visit. S/he may suggest a number of possible cures,
including filters for the interfering devices, as well as on the FM radio's power line,
antenna line, and audio cables. Experimentation with grounding some or all of your
components may also help.
A large variety of power line filters, and RF (Radio
Frequency) filters (for the antenna line and/or audio cables) are available from:
171 S. Main Street
Natick, MA 01760
If you confirm that a powerful local FM station is
preventing your reception of a weak, distant FM station on a nearby frequency, you can use
the "narrow IF" modes on good FM radios (described above) to improve
selectivity. A last-ditch attempt would be to try a special "notch filter" at
the antenna connector, to attenuate the interfering station. The Blonder-Tongue MWT-2b is
such a filter, and costs about $140 and is available from:
Blonder-Tongue Laboratories, Inc.
1 Jake Brown Road
Old Bridge, NJ 08857
P.O. Box 1416 Industrial Park Drive
Smithfield, NC 27577
The FCC's Web page offers a helpful interference
handbook at: http://www.fcc.gov/cib/tvibook.html
Or, call the FCC's Consumer Hotline: 1-888-CALL-FCC
If all else fails, and you have reason to believe
that the interference is malicious or illegal, contact the FCC:
Federal Communications Commission
Radio-Frequency Interference Dept.
191 M. Street N.W.
Washington D.C. 20554
The FCC is overworked and understaffed, and may not
be able to respond immediately (if at all). [Back to Index]
A possible solution, not available to everyone, is
your local cable TV company. Although many cable TV systems dropped all FM station
carriage some time ago, some systems still carry a few FM radio stations in addition to
the TV channels. Check with your local cable company. If they don't offer FM, register
your disappointment! Even though FM reception from the cable is often slightly degraded,
it's better than none at all. [Back to Index]
Books on improving FM reception:
Evans, Alvis J.: "Antennas: Selection &
Installation" (1989, Master Publishing Co. / Radio Shack) [very basic discussion of
TV/FM antenna techniques; good for beginners]
Salvati, M.J. : "TV Antennas And Signal
Distribution Systems" (1979, Howard Sams & Co.)
Sands, Leo G.: "Installing TV & FM
Antennas" (Tab Books) [Back to Index]
Publications on reception problems in general:
Fanfare offers a free booklet on FM reception called
"Rediscover FM Stereo," written by FM expert Marv Southcott, which is highly
recommended. You can get the booklet and info on Fanfare's excellent FM products from:
Fanfare FM http://www.fanfare.com
2100 Old Union Road
Buffalo, NY 14227
(800) 26-TUNER / 268-8637
A free booklet (number 004-000-00345-4) is available
from the U.S. government called "How to Identify and Resolve Radio-TV Interference
Problems" by writing:
The U.S. Government Printing Office
Washington, D.C. 20402.
The EIA publishes two booklets on interference,
"Something About Interference" and a more technical one called
"Technicians' Interference Handbook." Both are available from:
Electronics Industries Association
Consumer Electronics Group
P.O. Box 19100
Washington, D.C. 20036.
The American Radio Relay League, a Ham Radio
organization, publishes a book on how to reduce interference problems from Ham radio
transmitters and towers for its members. This book, called "Radio Frequency
Interference: How to Identify and Cure It," may be ordered from:
The American Radio Relay League
Newington, CT 06111.
[Back to Index]
Brinton, James: "Supertuners -- Are They Worth
It?", High Fidelity, December 1975, pp. 59-65
Clifford, Martin: "Language of High Fidelity
Part XI (Tuners)," Audio, May 1974, pp. 28-34
Feldman, Leonard: "An Empirical Study of FM
Antennas," Audio, October 1969, pp. 26-32
Feldman, Leonard: "FM Specifications
Revisited," Audio, April 1978, pp. 58-66
Feldman, Leonard: "New Tests & Standards for
Tuners & Receivers," Audio, Jan.86, pp. 38-44
Feldman, Leonard: "11 Outdoor Antennas
Analyzed," Audio, January 1983, pp. 41-47
Foster, Ed: "Interpreting FM Tuner Specs,"
High Fidelity, November 1977, pp. 72-75
Giovanelli, Joseph: "Remedying RF
Interference," Audio, January 1977, pp. 29-32
Hirsch, Julian: "Audio/Video Antennas,"
Stereo Review, May 1985, pp. 44-48
Hirsch, Julian: "FM Tuner Specifications,"
Stereo Review, November 1990, pp. 43-44
Hirsch, Julian: "FM Tuning," Stereo Review,
February 1980, pp. 35-36
Hirsch, Julian: "FM Tuners in Town &
Country," Stereo Review, February 1984, pp. 44-50
Hirsch, Julian: "FM Tuner Sensitivity,"
Stereo Review, Sept. 1981, pp. 35-36
Klein, Larry: "FM Multipath," Stereo
Review, November 1986, pp. 98-99
Long, Robert: "How to Read Our Tuner
Curves," High Fidelity, August 1988, pp. 46-48
Masters, Ian: "How to Get Better FM
Reception," Stereo Review, April 1991, pp. 70-72
Mitchell, Peter W.: "How to Buy a Tuner,"
Stereo Review, November 1987, pp. 93-97
Modafferi, Richard: "Kill FM Interference with
Two Antennas," Audio, January 1980, pp. 68-72
Riggs, Michael: "Basically Speaking: Radio --
the Inside Story," High Fidelity April 1986, p. 21
Riggs, Michael: "Front Lines: Progress in FM
Tuners?", High Fidelity May 1989, p. 5
Riggs, Michael: "How to Buy a Tuner," High
Fidelity, December 1980, pp. 50
Rosenberg, Fred: "FM Antennas Parts 1 &
2," Sounds LIke issues #5 & #7
Salvati, Michael J.: "FM Antennas"
[five-part series partially based on book above], Audio, January, February, March, April
1978, and January 1979
Sell, Gordon: "Tuner Design Forum," Stereo
Review, April 1982, pp. 49-53
Von Recklinghausen, Daniel R.: "How to Evaluate
FM Stereo Tuner Performance," Audio [month unknown] 1973 -- reprinted in 1974 Annual
Warriner, William: "RX for RF
Interference," High Fidelity, March 1976, pp. 56-59