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ii) Excessive noise is generated directly by the vehicle’s electrical
/ charging system - most commonly known as alternator
whine. This is only present when the vehicle’s engine is
running and recognized by the fact that the pitch or fre-
quency of the whine changes directly with the change in
engine rpm.
The preferred way to solve this type of problem is to have
the vehicle’s electrical / charging system serviced. The most
common cause of this type of noise is bad diodes in the
vehicles alternator. Other possible causes are: Bad vehicle
voltage regulator; Bad alternator or battery cable connec-
tions; Missing or bad engine or alternator grounding straps.
If servicing the vehicle’s charging system is impractical,
installing a good alternator whine power line filter in-line
with the radio power wire(s) will usually accomplish the same
thing. All radio power wires will have to be filtered. Some
radios have more than one wire that hooks to vehicle power.
Contact the radio manufacturer for a recommendation on
the best filter for the particular radio. NOTE: This solution
should not be considered a permanent fix. Vehicle charging
system problems of this type will eventually cause other
equipment failure as well as shorten the life of the vehicle’s
batteries.
2. Dispatch says too much background noise or unclear or weak
transmissions.
a) Check to see if a radio hand mic on the vehicle is also active or
“live” when transmitting through the UltraSound unit. Check
this while not wearing a headset and by talking directly into the
radio hand mic and pressing either UltraSound PTT switches.
Do not press the PTT button on the hand mic itself. If dispatch
can hear you loud and clear, then the background noise pick
up is coming from this active hand mic. If you have this type of
hand mic, then it is best to contact the radio manufacturer for
instructions on a possible microphone modification to fix the
problem. Some radio manufacturers can supply a compatible
microphone that does not have this problem.
b) Adjust the UltraSound Radio Mic Transmit Gain controls.
If the mic level is set too low, you will get reports of weak
transmissions. If the mic level is too high, you will get reports
of noisy or garbled transmissions. See “Radio Mic Transmit
Gain Adjustment”.
Radio 2 Hook Up:
Plug in J3 of the Radio 2 Interface Cable into P3 of the UltraSound
unit. Using the radio manual and Figure 5, connect the six wires to
the appropriate connections on the vehicle’s radio. Once that is done
you will need to set the RADIO 2 VOLUME switch on the back of the
UltraSound unit. See Figure 6. For most applications use the default
setting of “LO” (down - which is the reverse of the Radio 1 switch). If
the vehicles radio volume has to be turned up too high to hear it in
the headsets, set this switch to the “HI” position.
Next, set the Radio 2 Microphone Transmit Gain. The Radio 2
Microphone Transmit Gain Adjustments are the top set of the
two located on the back of the UltraSound unit. The adjustment
procedure is very similar to that of the Radio 1 Mic Transmit Gain
adjustment. First set the RADIO 2 MIC XMIT GAIN RANGE switch
to the “LO” position (default setting). NOTE: the HI and LO switch
positions for Radio 2 are upside-down from that of Radio 1. Arrange
to have someone nearby with a radio compatible with your Radio 2.
Then, proceed as follows:
1. Again, plug in a headset into Passenger’s jack. Make sure that
the volume control on the headset is turned up to full. (Radio 1
and the other headsets are not needed for this adjustment.) Set
the RADIO 1/RADIO 2 switch to “RADIO 2” and the AUTO/BOTH
switch to “AUTO”.
2. Put on the Passenger’s headset and position the headset micro-
phone as normal. Turn the UltraSound VOLUME control all the
way down (counter-clockwise). You should not be able to hear
yourself in the headset.
3. With the radio’s hand mic, transmit as normal, to the remote
station. Transmit long enough so that the receiving station can
get “calibrated” to your transmission (voice) level.
4. Verify Radio 2 reception. If OK, use Passenger’s PTT to transmit to
your receiving party. If receiving station reports weak transmis-
sion, use the screwdriver to turn the RADIO 2 MIC XMIT GAIN
ADJ clockwise a small amount. If they report garbled, broken,
or noisy transmissions, turn the RADIO 2 MIC XMIT GAIN ADJ
counter-clockwise a small amount. Repeat as necessary until the
receiving party reports that transmissions through the UltraSound
sound as good or better then when using the radio hand micro-
phone.
5. If the receiving party reports that your transmissions are still
weak with the MIC XMIT GAIN ADJ at the full clockwise position,
then switch the RADIO 2 MIC XMIT GAIN RANGE switch to the
“HI” position and repeat steps 3 and 4 above.
If Radio 2 does not operate as it should, use the “Radio Trouble-
shooting Guide” to find and fix the problem. This completes the
UltraSound installation.
HEADSET HOOK INSTRUCTIONS
The enclosed headset hooks are provided at no additional charge
to allow for a convenient way to store the headset. These strong
and durable hooks may be mounted in any location. Two mounting
methods seem to be preferred:
1. Top Mounting (Figure 7-a). The hooks may be mounted from
the existing headliner screws and hardware, or you may use the
enclosed attaching screws. When used with an electric driver
these screws are self drilling. For most metals such as aluminum
or common steel, they will not require a pilot hole. For some
stainless steels however, 1⁄8 inch pilot holes will need to be drilled.
Attach the right angle mounting bracket to the hooks with the
machine screws and lock nuts.
2. Side Mounting (Figure 7-b). The hooks may be mounted on the
side of the cab with the enclosed attaching screws.
Note: The right angle mounting bracket may be shortened (one
hole removed) by cutting with any standard hack saw.
This completes the UltraSound installation.
