Antenna boosters
Peter Galvin
information about increasing FM reception. I'm looking for something
to allow me to receive a clear signal from FM stations about 200 miles
away. I've seen adds for antennas which take AC power and replace the
standard FM antenna...but are these any good?! Please mail to me and
I'll summarize.
Thanks!
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--Peter
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Peter Baer Galvin (401) 863-7623
Systems Manager, Brown Univ. Comp. Sci. p...@cs.brown.edu
Box 1910 (115 Waterman Street) uunet!brunix!pbg
Providence, RI 02912 (02906) p...@browncs.bitnet
John Wells
Thanks!
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--Peter
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David Klippel
If you're referring the antennas that use house hold wiring as a feed line,
don't bother. Those antennas that plug into the wall outlet using one metal
and one plastic leads on the plug do use the house wirinbut are not technical
correct for FM reception. One half wave for FM is about 31 inches hence there
is no need for a whole house of random wire. Now if you're referring the
antennas that are about 18 inches tall and plug into the wall to power a
booster curcuit. Those are only good if you live within a city. I've had
first hand experience with this resently. The stations desired were within a
30 to 100 mile radius and the antenna provide no better reception than a twin
lead T. Unless you live in apartment or an area where you can not mount an
antenna even with an attic you best bet is an outdoor omni or directional
antenna. If you still having problems with receptions you can add a booster
to that type of antenna preferrable mounted at the antenna end to avoid
amplifying any line noise picked up on the way to the receiver. If this is
not possible then tried the indoor AC powered antenna as long you can return
it if not satisfied or you've got money to blow. The last alternative is to
subscribe to cable and pay $15-20/mo for reception of local and sometime
satellite stations. Hope this helped.
ProLine: davidk@pro-graphics
UUCP: ...crash!pro-graphics!davidk
ARPA/DDN: pro-graphics!dav...@nosc.mil
Internet: dav...@pro-graphics.cts.com
Peter Galvin
Here is the summary of responses I received to my query about FM
antenna boosters. The bottom line seems to be that boosters are
useful for filtering out strong signals, as happens in a city, but not
good at boosting distant signals since FM is basically line-of-sight.
The recommendation was to instead get an antenna higher off the ground
(such as using a current roof-top TV antenna.
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Here was a dissenting opinion though:
From: ma...@hsi86.hsi.com (Mark Sicignano)
At my parents vacation home in Vermont, they have a cheap JVC
receiver that picks up a few FM signals, but they are very
weak. They have an FM booster (Radio Shack I think). It works
very well. I assume that this is the case because in Vermont,
there isn't as much FM noise is there is in New Haven, CT
where I live. I don't think it would help me much here.
--
Mark Sicignano ...!uunet!hsi!mark
3M Health Information Systems ma...@hsi.com
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Also, this article was very informative. Thanks Konrad!
From: Konrad Omar Solomon <ks...@andrew.cmu.edu>
Hello, I consulted the owner's manual to my NAD Monitor Series tuner,
which has a good non-technical section on passive antennae. A summary of
everything follows, covering all the options you have. I included
everything since I'm posting this to the net, and so you'll be prepared
for any antenna jobs you may encounter..!
According to the manual, many components' "FM antenna input sockets are
designed to accept a 75-ohm 'coaxial' cable, a shielded type frequently
used with community cable systems, apartment building master antenna
systems, and most roof-mounted antennas." ok... this sounds like a lead
on the TV antenna idea but hold on... The impedance (ohm) ratings are
usually printed on/near connection terminals and antenna alike. Look
for them.
"If you want to connect an antenna with a 300-ohm twin-lead wire, use a
'balun' (an adapter containing a 300-to-75 ohm transformer)." ok...
The manual says simple antennas such as the T-shaped ribbon-wire types
that come with most equipment are "not very efficient at rejecting
'multipath' and other forms of FM interference, and cannot easily be
rotated to optimize its pickup pattern for best reception of stations in
different directions. Therefore, in most cases you should use a better
antenna. The recommended options, in order of increasing cost, are as
follows:
"(1) A basic 'rabbit-ears' indoor TV antenna without auxiliary coils or
tuning switches. Stretch out each of its two arms to a length of 30
inches (75 cm), orient them horizontally or at a shallow angle (less
than 45 degrees upward). The ribbon wire emerging from the antenna's
base should be connected to the balun adapter's screw terminals. Now,
for each station in turn, after you tune the station you can rotate the
antenna for best reception.
"(2) A more elaborate rabbit-ears antenna with a tuning switch. This
type of antenna does NOT have greater sensitivity... so if your problem
is that the signals you want to receive are weak... then an outdoor
antenna is the only effective solution." Peter, I suppose this means
your parents...see (4)
"(3) An electrically tuned idoor antenna... Again, such antennas
usually do not provide any advantage over the simplest type of rabbit
ears... but where strong signals are contaminated with interference, the
antenna's aiming and tuning controls can reject the interference and
yield cleaner reception.
"(4) An outdoor antenna. Even the finest indoor antenna cannot fully
exploit the capabilities of a good FM tuner. For the lowest noise,
minimum distortion, and largest choice of well-received broadcasts, an
outdoor antenna is the best complement to a fine tuner.
"A roof-mounted antenna has three fundamental advantages. First, its
large size yields better sensitivity (pulling in a stronger signal from
the desired station) and a narrower directional pattern for more
effective rejection of multipath reflections arriving from other
directions. Second, its location on a roof or tall mast places it above
many sources of interference- passing cars and buses, other buildings,
etc., Third, the strength of received FM signals is directly
proportional to the height of any antenna above the ground.
"If you already have an outdoor television antenna, using a splitter
to extract FM signals from it may produce excellent results. However,
many TV antennas are deliberately designed to be relatively weak at FM
frequencies in order to minimize potential interference with TV signals
at nearby frequencies (Channel 6 in the U.S.). You may be able to use a
splitter to extract FM signals from an apartment building's master TV
antenna system, but usually this yields poor results because many master
antenna systems have 'traps' to stop FM signals.
"The best choice is a directional FM-only antenna, mounted as high
above ground as is practical, and separated by at least two meters (7
feet) from other antennas, vertically and horizontally. If desired
stations are located in different directions (more than 90 degrees
apart), the antenna should be mounted on a rotor for aiming. Brand
names of good FM antennas in the U.S. include Herrold, Finco, Wineguard,
Antennacraft, and Archer (Radio Shack).
"Use shielded lead-in cable rather than plain 'twin-lead' wire, both
to minimize interference and to preserve strong signals during years of
weathering. The cable may be either 75-ohm coaxial or a shielded 300
ohm type. Disconnect any indoor antenna from the tuner before
connecting the outdoor antenna.
"If you install an outdoor antenna yourself, observe these important
CAUTIONS:
"1. Do not mount the antenna close to electric power lines. Plan
the installation so that the antenna mast cannot accidentally touch
power lines, either while you are installing it or later.
"2. Include a lightning arrestor in the installation, to protect
both yourself and the tuner circuit from potential danger during
electrical storms."
There you go. It sounds as though the existing TV antenna (you can
purchase a splitter at Radio Shack or similar) is the least expensive
good option, but if your parents don't mind (your?!) getting onto the
roof and some extra expense the separate FM-only antenna is clearly the
best option for receiving distant stations. This is enough information,
though, for ANY antenna installations you'll EVER have to do! Good luck
again,
Konrad
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Thanks also to:
r...@Eng.Sun.COM (Richard Pottorff)
johnb%srchte...@mathcs.emory.edu (John Baldwin)
John Whitmore <wh...@milton.u.washington.edu>