Phonak TX-300V User manual

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How to Optimize the TX300-V
Antenna
Introduction
The Goal of this memo is to present ideas how to
better optimize the use of the TX300-V. It will
document certain procedures that help users of the
TX300-V set the system up properly.
Antenna Installation
Antenna Installation
A. Selecting an Antenna Location
i. The location and configuration of your
antenna mount will determine the quality of
your signal; therefore, there are some
important factors to consider.
ii. Where will the receivers be located? Ideally,
the antenna will be centrally positioned
above that area.
iii. Where will the transmitter or stationary
receiver/power amplifier be located? We
recommend that it be located no more than
25 feet (7.6 meters) from the antenna.
iv. Are there any metal obstructions in the area?
Ideally, there will be no metal between the
antenna and the receivers. Also, try to avoid
mounting the antenna in a location where
nearby metal would be in parallel with the
antenna -- this degrades the signal.
v. Will the antenna be mounted outdoors?
Antennas work well outdoors, but if possible,
try to place the antenna where it will not
receive too much exposure to moisture or
dirt. Covering exposed connections with
petroleum jelly or silicone gel will extend the
life of the antenna.
B. Antenna Orientation
i. The antenna’s pattern is hemispherical,
meaning that it has an “active” side and a
ground side. The active side directs the signal
toward the receivers, so it is essential that the
active side be oriented toward the area where
the receivers will be used the Antenna
Module’s ground side has the word “GROUND”
molded into the plastic
ii. See Diagram A. If it is necessary to locate an
antenna low on a wall, the ground side should
face down. If you are mounting a monopole
antenna in a ceiling or high on a wall, the
ground side should face UP. It may be
necessary to move the ground side of the
antenna mount around in order to accomplish
this.
i. To move the ground side of the module, simply
remove the four nuts, reverse the module so
that the ground side is facing the bracket, then
re-attach the nuts. Be careful to not detach any
wires if the module opens while it is not
secured to the bracket.

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C. Mounting to the wall
i. We recommend using appropriate wall
anchors to mount the Mounting Bracket
directly to the wall.
D. Mounting to a wall box
i. The antenna may also be mounted to a
single or dual gang duplex box, or to a
square or hexagonal junction box.
E. Determine the correct length of the antenna
i. Determine the average of the highest and
lowest frequencies you will use with this
transmitter. (Example: If you are going to
use 182.50 MHz and 186.250 MHz then
take the average of 182.50 +186.250 and
then divide by 2=184.375MHz).
ii. Divide 7500 by the average frequency (in
MHz), then subtract 5 from this result. The
solution to this equation is the length in
centimeters to set your radials to.
(Example: 7500/184.375=40.68. 40.68-5=
35.68cm radial length).
iii. Extend the two adjustable length radials to
the calculated length (Example: 40.68
centimeters). Screw the two radials to the
antenna mounting assembly.
iv. Install the antenna mounting assembly in
desired location, preferably high on a wall,
away from any metal objects and with
minimal obstructions between antenna and
location of receivers and orient ground side
downward as indicated on the plastic
housing.
Connecting the Cable
1.Positioning of the coaxial cable
a. The coaxial cable should always run down
the near the ground radial. If the antenna is
inverted, the principle remains the same.
Running the cable near the active radial will
cause interference and diminish the range.
b. Connect the RG 58, 50 Ohm coaxial cable
to the BNC connectors on the antenna and on
the transmitter.
2.Connecting the BNC connectors
a. The BNC is connected by matching up the
pegs on the male connector with the slots on
the female end.
b. Once the two ends have been matched,
push down on the male connector to swivel
the connector until it locks the female.

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Strategies and Troubleshooting
1.RF Reception Maximization Strategies (from
TX300-V Manual)
a. For proper and dependable operation, Phonak
receivers need to receive a strong and
consistent signal from the originating
transmitter. The following strategies should be
used to maximize this signal:
i. When designing and installing your system,
keep in mind that the location of the
transmitting antenna is critical to maximize
broadcast range.
ii. Eliminate or minimize obstructions between
the transmitter and receiver(s).
iii. Minimize the distance between the
transmitter and receiver(s).
iii. Move the transmitting antenna away from
metal or conductive objects.
iv. Place the transmitting antenna as high as
possible.
v. Orient the transmitting antenna vertically.
vii. Position the RF Power switch on the back
of the TX300-V to full RF Power, unless lower
power is necessary.
vi. Extend radials to the correct length for
selected frequencies.
2.Cable
a.The TX-300V and antenna require the use of 50
Ohm cable. There are two cable types with this
resistance – RG-8 and RG-58 (RG-58 is supplied
with the TX300-V kit)
Using the antenna cable supplied with the unit is
sufficient unless this cable distance is greater than
15m. Because of the amount of attenuation, the
RF power loss, at lengths greater the 15m with RG-
58, is too large and a degradation of the signal
power will occur.
b. It is encouraged to use RG-8 at lengths greater
than 15m.
3.Troubleshooting Questions and Answers
a. There is very limited range between the
transmitter and receiver
i. The first thing that needs to be checked is the
length of the antenna radials. Review the
information above to be sure that the lengths
are correct in correlation with the desired
transmitting frequency.
ii. Make sure the antenna has been placed in an
area free of metal obstructions.
iii. Check the operating power of your transmitter -
there are three settings, ¼, ½ and full power.
Increase the power if it’s low.
a. I cannot hear anything from my receiver
i. Make sure the receiver’s batteries aren’t
dead, that it is turned on, set to the right
channel, and the volume has been turned
up.
ii. Make sure your transmitter or stationary
receiver has been powered up and set to the
right channel, and the desired audio has
been applied.
iii. Make sure the coaxial cable has been tightly
attached to both the antenna and the
transmitter/ stationary receiver.
iv. Make sure you have used 50 ohm coaxial
cable.
v. Make sure the antenna element(s) has been
securely attached to the Antenna Module.