Page 6 - November 2021 Track N Times

TECHNICAL TRAINING

The Radio, A Vital Link For Loram

By Jason Young, Manager, Power-Control Services

We often take for granted the radio that is by tion and is clear of interfering structures, they
our side. Either clipped to our vest or installed in should be able to send the message out over
our machines, the device we’ve become accus- considerable distances. Particularly, the ‘base
tomed to is the product of many years of devel- units’ mounted in the cabs.
opment and evolution that nowadays has be-
come a staple of everyday life at our workplace. When a radio is having trouble reaching out to a
station that is more than a few miles away, it is
Not that long ago, communication on the rail- almost always the fault of the antenna. If you
road comprised of a series of visual hand signals can hear the suspected transmitter clearly on an
or written train orders that were physically adjacent receiver, a quick way to test this is to
handed off to consists operating on the way. To- attempt to monitor the weather channels. You
day, we have highly effec- should be able to pick up at
tive devices that allow us least 1 to 2 weather channels
to communicate with our very clearly depending on
peers instantaneously your area. If you cannot,
with little effort on our then it is likely that the an-
part. All we must do is tenna or its connections are
key the “Mic” and speak faulty. This can usually be
to whomever we wish to resolved by tightening the
contact. silver plug on the back of the

Let’s understand how this radio. If that doesn’t do the
“miraculous” device trick, further inspection of
works. the cables, connector, and
the antenna itself is in order.
When you “Key the Mic”
or push the transmit but- A check with an ohmmeter
ton, the radio switches between the outside ‘shield’
instantly from receiver of the antenna connector
mode to transmit mode. and chassis ground should
We won’t go into the details of how the radio show ‘zero’ or a very low resistance. A check
does this, only that there are three very im- between the center pin of the connector and
portant parts of the system that makes effective ground should show a very high resistance. If
radio communication possible: Microphone, Ra- this looks okay, and you can safely access the
dio Set, and Antenna. antenna for inspection, look for loose or cor-
roded parts. If these are okay use an extension
Modern radio ‘transceivers’ are highly reliable wire to check continuity between the center pin
pieces of technology that in themselves are of the radio coax connector and the antenna
mostly self-contained and require little mainte- whip itself. This should show close to zero
nance. If a transceiver has a good power connec-

Volume 2 : Issue 10 Page 4