Transmitter facilities hold a special fascination for radio
engineers. Ranging from spotless high-rise suites to dirt road shacks,
the "site" as is it's known in the professional vernacular, represents
a station's final, vital link to the listener. Consequently, it
sometimes also serves as a repository for an engineer's blood, sweat
and tears — so let's take a closer look at what it takes to
maintain a safe and efficient operation at these mission-critical
Thorough and up-to-date documentation are fundamental to maintaining
a robust transmission facility. Because the location serves as a
control point during maintenance, copies of all current FCC licenses
and authorizations, including chief operator designations and tower
registrations, are required. But the legal obligations don't end there.
OSHA regulations generally require a written, up-to-date
lock-out/tag-out policy for all hard-wired, electrically powered
equipment, along with approved locking devices and tags. Document in
detail any areas (including areas on towers) that constitute a
non-ionizing (RF) radiation occupational exposure hazard, as well as a
policy regarding access and exposure limitations. Being a lessee at a
site does not relieve you of any of these obligations — check
with the owners to see if a master site plan exists. If not, work
together to develop one.
Equipment data such as manuals and schematics should be maintained
on site for all essential systems. In addition, keep a list of
essential phone numbers, including hot lines and key personnel along
with local FAA, utility and safety service contacts. Attach a list of
all telco circuit designators and the associated trouble reporting
While most contract engineers carry
their own tools, the transmitter site should be stocked with some basic
If you had to call for police, paramedic or fire help, would they
know how to find your facility? Contact representatives from all local
safety services to make them aware of exactly who, what and where the
facility is located. The difference in response time might save a
Keep detailed records. Although, the FCC lifted requirements for an
official maintenance log years ago, keeping an organized, detailed,
running account of all operating parameters, equipment installation,
maintenance, outages and discrepancies is absolutely vital to the
operation. Keep your FCC-mandated quarterly tower inspection among
these documents and maintain them for a minimum of two years —
they represent an irreplaceable information resource.
In addition to written records, a comprehensive flow chart/block
diagram of the entire air chain, complete with all remote control
switching functions, is an invaluable trouble-shooting aid, on-site and
off, particularly when you are maintaining multiple transmitter
Tools and technology
The question of how many and what type of tools to maintain at a
transmitter site is an interesting one. Most contract engineers I know
rarely set foot out of the house without their tools, so the need for
an on-site inventory is partially diminished. Still, it's a good idea
to have a minimum compliment of screwdrivers, pliers, wire cutters,
adjustable wrenches, socket wrenches, hex keys and soldering aids on
site. Also, any large or specialized tools such as vises, fuse pullers,
pulley removers or pry bars should be available, along with a reliable
trouble lamp and spare bulbs. This need not be an expensive
proposition. Keep a shopping list for each site and pick up tools on
sale (or used tools) until the desired inventory is built. Done this
way, a minimal investment of $100 can yield a useful selection.
Likewise, a minimal stash of fasteners, particularly #4 through
¼" machine screws, washers and nuts are a cost-effective
investment, particularly when one disappears down a crack at 3 a.m.
Premium electrical and duct tape are equally indispensable.
A reliable DMM with appropriate test
leads and spare batteries should be kept at a transmitter site.
The characteristics of any maintained electronic parts inventory
depends largely on your equipment, its history and the available
budget. Full sets of spare tubes and fuses are a must, but your own
experience with each piece of equipment will tell you a great deal
about which other specialized and non-specialized electronic components
to maintain. Equipment redundancy will also impact your parts inventory
As for test equipment, this is again a case of what the budget will
bear. At minimum, a reliable DMM, with multiple test leads and spare
batteries should be present. An oscilloscope is a nice option, but
should be kept in a protective case and tested periodically. Telephone
butt sets and volt pens are also useful.
Finally, don't overlook cleaning supplies and chemicals. Straight
isopropyl alcohol is a good cleaning agent for inside transmitters when
teamed with lint-free shop towels. Spray contact cleaners are a key
item, as are cleaning swabs and toothbrushes. Of particular merit is a
shop-vac; a bulky item, but it will be used regularly.
Safety is paramount at every transmitter facility. Items that should
be readily accessible when you walk through the door are a flashlight
with spare batteries and a recently inspected fire extinguisher. Once
inside, there should be an obvious place for a hard hat, safety gloves,
goggles and kneepads. If you have a generator, hearing protectors are
also a must. Additional site keys for gates and buildings should be
clearly tagged and hung together in an easy-to-see location. Safety
signs and notices should be posted wherever they are required.
As a final cautionary note, try to appreciate the critical need for
having a buddy — anyone capable of watching you and able to call
for help whenever you have to open energized or disconnected
high-voltage equipment. Your life, and the people that depend on you,
hang in the balance.
Backing up the back-ups
There is one last item worth considering for your site. An ISDN
circuit carries a low monthly maintenance fee, can be used for POTS
communications (with an ISDN phone) and also provides a potential
air-quality link to any location in the outside world, should an STL
path be disrupted or a studio facility be rendered unusable due to fire
or other disaster. If you don't own an ISDN codec, find someone locally
who does and forge a loan agreement in the event of an emergency.
Better yet, work out a reciprocal agreement for sharing studio or
transmitter facilities should the worst occur.
Krieger, BE Radio's consultant on contract engineering, is
based in Cleveland and can be reached at firstname.lastname@example.org.