Hafler 945 Will Poor quality Could be Source Noise This, By a High, Noise, rather than a hum

FM ANTENNA

WARNING: The use of ground adaptors (with the ground tab or wire of the adaptor disconnected) will eliminate the safety feature of the grounded power cord. This safety feature is intended to reduce the risk of electric shock-should an internal fault in the equipment result in an electrically “live” chassis. Therefore, this method of ground isolation should be employed only when absolutely necessary, rather than as a general practice. When using a ground adaptor for isolation, make sure that the power cord plug is inserted into the receptacle in the same orientation as if no adaptor were present, to maintain the same hot/neutral polarity.

SPECIAL NOTE ON VIDEO CABLE “GROUNDS”: As mentioned above, the ground conductor of cable

service and antenna feeds should be connected to earth ground. Often, however, due to long feed

lengths,

especially

in

apartment

distribution systems,

this

ground

will

be

of

poor quality

and could be

a

source

of

noise.

This

interference is usually characterized

by a

high

frequency

noise, rather than a hum

or

a buzz.

If such interference

is experienced, a separate earth ground

connection should be made from

the

cable

outlet

nearest

the

audio/video equipment to a known good

earth

ground.

If

ground

loops

exist

due

to

potential differences

in the

interconnects

in

rack

mounted

systems, then

it

is advisable to isolate the preamplifier chassis from the rack rails. This may be accomplished by

sandwiching a	thin	sheet	of	insulating material	(i.e.,	plastic washers or several layers of electrical	tape,
etc.) between	the	rack	and	the preamplifier,	and	securing the unit with non-metallic (i.e., nylon,	etc.)

hardware. It may be necessary to insulate other components so that only one component is directly connected to the rack rails.

The ribbon dipole antenna supplied will offer excellent reception in most situations. To maximize the reception potential of this antenna, a few guidelines should be followed:

- fully extend the “arms” of the dipole

- mount the antenna as high as possible

- mount the antenna away from large metal structures

- orient the antenna perpendicular to the direction of the radio station’s transmitter.

Some experimentation will be necessary in less than	optimum	reception areas, or	where	reception of
a distant station is desired. Often, an adjustment of a	foot or	so in antenna position	can	affect reception
noticeably.

A number of alternate indoor antennas are available, from traditional “rabbit ears”, to antennas designed specifically for high quality FM reception. Although these units offer little or no advantage over the ribbon dipole in terms of gain or directivity, they are typically table mounted, offering greater flexibility in placement and mobility.

For the ultimate in FM reception, especially in difficult reception areas, an outdoor antenna is recommended. There are two basic types of “poor” reception conditions. Urban areas may be characterized by strong signals, but those signals can be interfered with by reflections from tall structures. Rural areas may be characterized by weak signals from distant stations.

There are

many

types of

outdoor antennas. Some

may be

optimized

for

directionality,

while

others may

be

optimized

for high

gain.

It is

best to seek local advice for

analysis

of your specific reception

conditions.

In

addition

to

the

300

ohm

FM

antenna terminals, a

standard

"F" type

75

ohm coaxial

antenna

connector

has been provided. The use of this input, using coaxial cable, is recommended for outdoor use, to

minimize noise interference. This	input should	also	be used for connections to FM cable services. Again,
seek local advice for choosing	a cable type	for	your application.

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