There are the
solutions to each of the problems above that
will be discussed below.
Driver Arm Length
Good wired and wireless intercoms use amplified speakers that produce plenty of volume, so the driver does not have to get very close. You can also install an optical sensor on the outside intercom that will automatically call the scale operator. To talk to the driver, the scale house operator just presses the talk button on the inside intercom, and the truck driver can then talk hands free.
Most good systems are full-duplex wireless so conversation is more like a phone call. Once the call is setup, the system goes into transmit and receive mode on both sides and both parties can carry on a conversation.
If the driver can get out of the truck and push a button to talk, then a wireless callbox can be used to communicate with the scale operator. What's beneficial about this application is that the scale operator can use a handheld two-way radio to talk to the drivers so he or she doesn't have to be confined to one location. You could also use a basic wired intercom system as well since the driver is likely away from the noise of the truck.
There are two problems to be solved for a truck scale intercom system:
1. The trucks are very loud and scale operators can’t understand the drivers.
2. The truck scale intercom needs lots of volume to overcome engine noise.
It's easy enough to amplify sound so the driver can hear, but the hard part is the scale operator side. Two technologies are required to make this work well: Acoustic Echo Cancellation (AEC) and Active Noise Cancellation (ANC).
Acoustic Echo Cancellation is required for full duplex and is used to cancel feedback (squealing noise) on the truck scale intercom. The higher the volume, the harder AEC has to work. It takes expensive processing power and complex, patented software algorithms to make this happen. Now add noise cancellation and it takes even more processing power. Lower cost systems don't work well because they can’t use the quality components and engineering needed to give you both volume and understandable conversation.
There are wired and wireless full-duplex systems that solve both of these problems.
If the driver
doesn't have to push a button, you can mount
the intercom or horn speaker somewhere in
between the differing heights and you should
be OK. If you use a system that does require
button pushes, then there is a 72" & 42"
Dual-Height, Pad-Mount Pedestal Pole where
you could mount two intercoms.
Depending on the scale installation, it may
be virtually impossible, or at least far too
expensive, to install cable for a wired
system. Trying to bore or cut through metal,
asphalt, or concrete can add thousands to
the installation cost.
However, there can be obstructions for a
wireless system as well. Buildings, hills,
or even the truck itself are obstructions.
The best signal will be obtained with clear
line of sight between the inside and outside
units. It's not absolutely necessary to be
able to see between points since radio
signals do bounce around. But, your chances
of success will be reduced, especially if
you go with a full-duplex intercom that uses
900mHz as its frequency. 900MHz systems have
lower power than a system that uses VHF or
UHF, but the feature set is greater and may
be needed. There are ways to overcome the
obstructions by raising the antenna height
over the truck, or by installing high gain
antennas mounted as high as possible. If you
want to learn more about how far wireless
communications can reach, the article and
video at this web address will help:
If you can't run wires, you also may not be
able to get power to the location where you need
the intercom. A self-contained solar power
system may be your only option. What wattage
solar panel you choose depends on several
factors, but the greatest will be determined
by the number of trucks that run through the
scale daily. If you have 200-300 trucks a
day, a 50-watt system will likely do it for
you, while fewer trucks than that you can probably
get by with a lower wattage system as long
as you don't have cloudy days for days on
If your scale
operators are roaming around, you'll need
some way of notifying them that a truck as
arrived. If they are far away from where
they need to be, then you may want that
notification to occur even before the truck
has arrived so the operator can get back to
the scale house. You could install a motion or photo beam sensor earlier in the
path of the truck. But if you are using a
full-duplex intercom that automatically
turns on then you'll still need detection at
the intercom system as well.
If the trucks coming on to your scale are
pretty much all the same length, then where
you put the intercom depends on where you
want the trucks to stop. If they are varying
lengths then you may need to put the
intercom towards the front of the scale as
long your scale measures accurately with
small trucks this way. Regardless, you may
need signs to tell truckers where to stop.
Wired systems are the lowest cost but you
have to factor in the labor cost to run
wire, which can be astronomical. A full
duplex wireless system is very expensive,
but depending on the features you need, it
may be your only choice, and it still may be
less than the labor cost of installing a
wired system. If you have to go with solar
power that's going to add quite a bit to the
cost as well. Either way, wired or wireless,
installing a system may save you money in
the long run through increases in
productivity and efficiency. Truck Scale Intercom Systems
intercom experts at
www.IntercomsOnline.com and we can help
you choose the right truck scale intercom
system for your unique application. To see the systems we offer click here: