FOR YEARS, broadcasters have
r been faced with the FCC
"bugaboo" of logging semi-hourly
transmitter readings. Everyone
knows what a pain in the neck it
is to have to make these readings
by the clock. In this day and age,
and especially where modern and
reliable transmitter gear is used,
tedious meter reading and logging
often seem a waste of time. Yet,
one cannot deny the validity of the
Rules, nor the value of properly
logged data in preventive maintenance. Thus, it is only natural
that more and more stations are
resorting to automatic logging
equipment as the logical solution.
From a survey of many users of
such equipment, logging accuracy
is immeasurably better, and a constant, continuous, permanent log
of transmitter parameters is provided. It is very easy for a busy
operator to overlook regular halfhour reading times. When a chief
engineer inspects a manual log, he
can't be positive of its accuracy.
An automatic log chart, on the
other hand, gives him truer and
continuous operational readings.
Slight changes in operating constants, indicative of impending
trouble, can easily go unnoticed
in half-hour readings, whereas a continuous recording will readily
show intermittent momentary
variations.
Effects on Manpower
Aside from the engineering
values of having an automatic
"watchdog," and a continuous record of transmitter performance,
are there any other advantages to
be gained? Very definitely! Numerous stations using automatic
logging equipment are unanimous
on this point.
Automatic logging has freed
transmitter engineers and operators from long, boring transmitter watches to handle other important jobs in the control room,
in production work and in maintenance. A multitude of financial
gains have been derived from more
useful deployment of personnel in
various phases of operation. Some
stations have reported cutting
transmitter staffs in half, thereby
providing much needed manpower
for maintenance and production.
One station reduced its transmitter staff from four to two men.
Two were reassigned to studio
work and the remaining two maintain the equipment and manually
log entries during nighttime operation. Another station reas signed three of four men to studio
control, leaving transmitter supervision to a resident operator. At
still another station, one man has
enough time to maintain visual
and aural transmitters, two microwave receiving stations, an FM
transmitter with two SCA operations, and an FM standby transmitter. Previously, a large part of
his time was spent merely logging
transmitter readings. Although
it's not required (as long as
licensed operators are available in
emergencies), many stations keep
one man at the transmitter,
charged with maintenance responsibilities and an occasional check
on overall operation.
Equipment Performance
Automatic loggers are meeting
and exceeding the expectations of
the chief engineers we talked to.
Initially, though, some didn't find
everything so rosy. Some problems were encountered in matching sampling voltages to logger
requirements, and a bit of experimentation was necessary to produce the required levels. While
most logging equipment will accept a fairly wide range (10v or
so) of input sampling voltage,
high plate voltages and currents
are tricky to reduce to acceptable
levels. Engineers who have worked
with remote control gear will find
their experience quite useful. If
you are installing a remote logger,
the sampling voltage problem may
not be so complicated since you already have data coming in from
the transmitter at levels suitable
to most loggers (if yours is a DC
system). However, in a few cases,
line noises interfering with logger
accuracy were reported. This presents a particularly knotty problem since phone company line
quality is involved, and the only
solution is to improve line quality. Transmitter RF on phone or
sampling lines, especially if it's intermittent, gives erroneous readings until it's tracked down and
eliminated.
Components used in sampling
and alarm circuits, and in the logger itself, must be of the highest
quality; at least comparable to
broadcast equipment standards. To
sacrifice quality is to invite all
sorts of problems: repeated failure, difficult calibration maintenance, and the risk of inaccurate
readings.
Also, personnel must become
familiar with the equipment, which
is unlike most other broadcast
gear. Adequate installation time
serves as a "get acquainted" period
and allows for accuracy and stability checks, and "debugging."
One chief expressed, as his only regret, allowing insufficient installation time.
Importance of Maintenance
An automatic logger without a
properly moving recorder chart is
less than useless. When a new roll
of paper is installed, special care
must be taken to insure that it is
inserted properly and moving at
its proper pace. If carelessness in
setting up the recorder is permitted you may discover later that
you have no operating log for an
entire day! Chart paper quality
is of utmost importance; use of
cheap, off-brand paper may result
in sprocket hole tearing, as it did
in one station, which wound up
with no operating log for several
hours.
Logging Procedures
Some stations remove the length
of chart at the end of each broadcast day and attach it to a daily
log sheet containing carrier on
and off times, tower light records, DA phase reacings, etc. Others
leave the roll chart in place until
used up before ffling it in the records. In the latter case, the date is
stamped on the chart at the beginning of each day.
What About Costs?
Surprisingly, automatic logging
equipment is fairly reasonable,
ranging from a minimum of
$2,000 to as high as $5,000 where a more complex installation is involved. TV and AM-FM stations
will need two loggers to accommodate both transmitters.
Automated logging installations
in remotely controlled stations require phone lines capable of carrying DC. If existing lines fulfill the
requirements, without disrupting
remote control and fail-safe functions, installation costs will be that
much lower. If transmitter sampling circuits do not exist, they
will have to be installed. If the
transmitter was designed for remote control, at least some of these
sampling circuits can be adapted
to feed the logger. Manufacturers'
recommendations should obviously
be closely followed. Sampling voltage levels are critical; if they are
not at recommended values, logger calibration will be difficult to
adjust and maintain.
Most logging equipment uses internal relays to operate external
parameter tolerance alarms, but it's up to the station to devise necessary alarm apparatus. Bells,
Duzzers, flashing lights, or any
combination of devices which will
attract attention will do the job.
Intermittently ringing bells and
buzzers and flashing lights have
been found to attract attention
more readily than a steady ringing
or buzzing, or a constantly glowing light.
Is Automatic Logging For You?
While it may be possible to do
so, it usually isn't practical to discharge transmitter staff personnel
whose jobs are eliminated because
of automated logging equipment.
Most stations have found that they
have a need for technical personnel in other phases of their operations. On the other hand, after a
period of stabilization, an employee who resigns may not always
be replaced.
From a manager's viewpoint,
automated logging makes it pos sible to accomplish more with the
same number of people, and to enhance better technical operation.
There are many ways to use an
engineering staff's additional time
to advantage — more thorough
maintenance, for example. Better maintenance is almost like money
in the bank!
Your situation must, of course,
dictate whether or not automatic
logging will be advantageous to
you. Stations using it say it's a
wise investment.