Photo courtesy of Richland Towers Inc.
A robust transmission system is one that provides superior signal
and audio quality, and provides this superior product even in adverse
conditions. The system should also be fault-tolerant, and easy and
inexpensive to maintain. Furthermore, remotely located systems should
provide accurate and timely information about site conditions to remote
users and maintenance personnel so that decisions can be made quickly
in emergency situations.
All of these concerns must be addressed in each phase of a project -
design, construction and maintenance.
The design phase
Because engineers are usually asked for their input, it is incumbent
on the engineer to make his client or employer aware of the relevant
issues and their relative weight, so that the client can make good
decisions. There are times when the engineer may feel as though he is
saving his clients from themselves — and there are times when
that is true — but remember that management counts on the
engineer to know the issues. Pounding the table once in a while to get
a point across is OK; after all, a few bruised egos are better than
being stuck with a bad site — but be careful not to sneer at
non-technical types. Don't let an ego get in the way, either. I've been
too pushy on projects before, and I have gotten myself fired more than
once, too. In the end, the client got a bad facility because he hired
an easy-to-get-along-with engineer, and I lost the money and the
satisfaction of finishing the job after I had laid all the groundwork.
This was a lose-lose situation for sure.
The chosen transmitter site should
provide adequate coverage of the desired signal area, which may not
necessarily be the city of license.
The chosen site should provide good coverage of the desired area,
which is not always the city of license. The character of the land
should be considered with height of terrain being of the greatest
interest for an FM station and low, flat land with good conductivity
being paramount for an AM station. Use the station's consultant if
possible. A good consultant is well acquainted with site selection
criteria, and he may have a few tricks, too. He can earn his pay in
avoided pitfalls due to his advice.
Remote land is often chosen for transmitter sites due to low
acquisition costs, but keep in mind that access roads to remote sites
are expensive to clear and maintain, and management may balk at the
continuing costs. Another potential problem with remote sites is the
quality and availability of commercial ac power. In rural areas, the
power company may be unwilling to provide three-phase power (or any
power) without high up-front costs, and the station may find itself on
the end of a long and unreliable power line with poor regulation, large
numbers of surges and poor power-failure response times. Any assessment
of a potential site should include input from the local power company
and also from other stations in the area or other nearby customers
— even residential ones. This is also true for telephone and any
other utilities that may be desired at the site. Projects can be
delayed at the last minute because management foolishly assumed that
anything they needed could be provided in short order by the utility
companies. Sometimes utility or access road issues can swing the tide
in favor of a more expensive but more accessible site. Because this is
one of the first decisions made for any facility, be sure to obtain the
pertinent facts early in the project.
Make sure that your client or employer knows the issues regarding
tower height vs. coverage area vs. price, and number of FM bays vs.
coax cable and transmitter size. If an ill-advised decision is made,
speak up. I recently had a client decide to diplex a low-band AM
station at a higher-frequency AM site with a short tower — too
short for that low-band signal. I advised him so, but the client went
ahead anyway. The FCC refused the application, citing the short tower
height. Now the station owner is building a taller tower, and I believe
that this will serve the low-band station better.
While remote land may offer an
attractive acquisition cost, adding commercial power and access roads
may counteract the savings.
Simple but true: Buy good equipment. Of course, it gets complicated
in a hurry when faced with choosing between a major manufacturer or a
less expensive manufacturer, installing an auxiliary transmitter, STL,
antenna, processing, dial-up or dedicated remote control, a coax switch
or a dummy load. It's better to have one set of first-class equipment
than two sets of substandard equipment.
Budget the essential items first, such as surge protectors, proper
tower and building ground systems, generators and radomes. All too
often stations try to cut budget corners by forgoing these
infrastructure items because they are all but invisible; they add no
capabilities and therefore have no champions, no constituencies. If a
station doesn't budget for them now, it will have a hard time getting
them budgeted later, and then only after the station is crippled and
someone may have to take responsibility. Nobody ever wants to hear
“I told you so.” Do everything possible to fight for these
orphan (but essential) items now. Most managers know how hard it is
when choosing what to cut from the budget, and they are usually aware
of the bad (if delayed) consequences of their actions.
If you can't afford new equipment, consider used equipment.
Late-model, good-quality used equipment will almost never turn out to
be a lemon, and an engineer can probably save enough money to put some
of the extras he thought he was going to have to do without back into
The more inaccessible the site, the better the remote control should
be. This applies to all backup equipment. For a truly remote site, the
remote control should have complete control over all transmitters and
should monitor everything in sight: full transmitter metering/status
including internal overloads shown separately from VSWR; extensive site
monitoring with ac power including phase loss, site and outside air
temperature, site intrusion and security, full tower light monitoring
and STL signal loss and generator monitoring.
A backup power generator is an essential
item at a transmitter site, particularly in remote locations.
No matter how good the equipment is or how carefully the site is
selected, the radio transmission system won't be robust if the building
itself is falling down. Buildings that are too small don't work well
either. Make sure that the building is built well for its location and
is big enough to accommodate present equipment needs with enough room
for reasonable expansion. Think about concerns such as ceiling height
and required RF plumbing before you are forced to put equipment such as
coax switches where they hit you in the head every time you walk
The construction phase
This is where all the decisions from the design phase are
implemented. It falls on the project engineer's shoulders to make sure
that the subcontractors install the subsystems in accordance with the
design. Be assertive. An engineer only has to make one subcontractor
redo work for word to get around that he is to be taken seriously. Make
sure that management backs you up — this is important.
If the project engineer is not going to climb the tower to check
their work, use a tower company. Even then, check everything possible
from the ground. Make sure that they properly handle items that are
small to them, and therefore often easily overlooked, such as grounding
kits or tower lighting conduit weep holes. If the subcontractor gets
the idea that shoddy work and cut corners won't be tolerated, he is
more likely to expect that standard for all the work at the site.
Don't let any subcontractor off the site without double-checking his
work. Make sure that everyone knows that they may be called back if
problems develop. If possible, arrange for some percentage of their
payment to be withheld until the station is on the air and everything
has been observed to run properly for some period of time (10 percent
for 10 days, for example). This gives them a clear incentive to make
sure that the station is happy as a customer.
A clean and organized transmitter site
makes a more efficient work environment, particularly during emergency
Arrange for work, such as grounding or wiring in the slab or walls,
to be inspected before it is covered. Don't rely on city or county
inspectors for this because it isn't their site. Don't forget small
items such as fence placement and FCC-required signage.
No matter how well designed or built, a facility has to be properly
maintained or it falls apart.
Fighting persistent failures that consume all of the engineer's time
and parts budget is not efficient. Lack of good surge protection or
grounding, poor-quality or worn-out equipment, or equipment poorly
sized for the job are the usual culprits. These issues have to be
addressed, and quickly once an engineer is put in charge of a
particular site, or else management will lose faith in his ability to
solve the problems. If the failures are obvious enough and often
enough, then the engineer should not have much trouble making a case to
management of proper remedial action. This clearly takes precedence
over all other issues, except perhaps pressing legal ones.
Once the facility is in proper working order, establish a good set
of site supplies and parts, and a maintenance schedule and budget that
provides not just for the upkeep, but also for the improvement of the
facility. Never visit a transmitter site without making some
improvement in the site's functionality, cleanliness, or supply
If the facility has old equipment, develop a plan for replacing it.
To do this the engineer will need to speak the language of management:
It pays to go to management with good numbers for any budget,
especially for new equipment. Show them the benefits of the new
equipment. Does it use less power? How much? Does it take less
maintenance? Is it solid-state instead of tube? Show the savings in
eliminated tube costs. Make the numbers tell the story. Another thing
to consider is whether the equipment be leased? Do the homework. Get
programming on your side — even sales. It's hard to sell a
product that's not on the air, or that sounds bad. Be creative, even if
you're just trying to get a new piece or two of equipment. It never
hurts to be perceived as a team player, either.
As with new sites, sometimes the purchase of good used equipment is
a smart move. Don't get fixated on the all-or-bust mentality.
Compromise is often the order of the day.
It's useful to establish end-of-life criteria for each piece of
equipment at a site; some calendar date or failure point after which it
is clearly time (and hopefully budgeted) to replace that equipment.
Once that date or condition arrives, stick to the schedule. Don't let
anything be a sacred cow. Every piece of equipment at a radio station
has a useful life span, beyond which trying to maintain it is no longer
smart engineering. Don't be afraid to put a value on it.
Transmitter site maintenance goes beyond
the transmission equipment. Vegetation, like this section of tree that
grew into a guy wire, must be cleared from the site regularly.
A site should always be thought of as dynamic, never as fixed. This
year management may only replace a few parts, but next year the station
may need a new audio processor, a new remote control or even a new
transmitter or tower. The budgets should reflect this. Don't let
management get the idea that the entire equipment set at a site is set
and need not be looked at until it comes time to completely rebuild
that site. Even worse, don't provide the feeling that the site will
last forever. The “state-of-the-art” changes all the time.
Look at the number of generations of audio processors developed
recently. Budget in such a way that the site is not falling hopelessly
behind. Get management to replace something every year at every site,
even if it's only to upgrade the firmware in the remote control, so
they don't get the impression that they can write off upgrades.
The equipment that can't be replaced must be maintained. Get in
there and clean. Even at sites without water, it's easy to bring
containers of water, alcohol or other solvent or surfactant, large
enough to clean any equipment or mop the floor.
Pay attention to how a transmitter is vented and what effects that
has had on its level of cleanliness. In terms of transmitter
cleanliness, it pays not to use an extern-ally-vented air system, but
instead to install a sufficient air conditioner to handle the heat load
of the transmitter, keeping the transmitter in a closed system. This
re-duces the dirt in the transmitter — dirt that ends up in the
tube socket and on the HV supply wiring or gets sucked into blower
bearings and deposited onto heat-sink fins.
The older the equipment, the more aggressively it needs to be
maintained. Don't forget to change old electrolytic capacitors, old
relay contacts or old bleeder resistors. Keep all the indicator lights
working. Sometimes this requires coming up with innovative ways of
doing that, such as using solid-state light bulbs, reduced voltages or
shutting off the voltage to the indicators when no one is there to see
Site and building maintenance
Be proactive. Look for things like peeling paint and rotting boards
before the whole TX building wall is sagging. Don't let weeds become
overgrown. Keep the road passable. Don't let locks get rusty or else
they will break a key at 3 a.m. in the rain.
Spending time at transmitter sites is usually not fun, and all too
often management's attitude seems to be that if the engineer isn't at
the studio, he isn't working. But it pays to stay ahead of the curve.
An engineer who only visits his transmitter sites when there is an
emergency is just asking for trouble.
Any budget worth the paper it's printed on should take into account
building maintenance, tower painting and other infrequent occurrences.
If management is reminded that these items are on the horizon, even if
it's not this year or next, they'll be much more willing to budget the
money when the time comes than if it's sprung on them.
A robust transmission system is not just within the reach of
big-city engineers. I have seen nicely equipped sites in small towns,
and I have seen some poorly maintained sites in big cities. Creating a
first-class site is possible with a little help from management.
Attitude will go a long way toward obtaining that help. So, next time
you go to a transmitter site, bring some fuses, and a bottle of water,
and a flashlight, and …
Patton is president of Michael Patton and Associates, Baton