Translators for AM: Owners, Don’t Get Your Hopes Too High
The author is owner of WGTO(AM) and W266BS in
Cassopolis, Mich. His commentaries are a recurring feature in
Are you doing the translator
scramble?Yes, the FCC move to
get more translators in the hands of AM stations has been met with a bit of
controversy; but all that notwithstanding, I want to take a moment to make sure
that no matter how you get a translator, be warned it’s still going to be a
crapshoot. It’s not a full-service FM station by a long shot.
Translators have very little protection, and unless you get up high on a
building or tower the range may be disappointing. You will want to work closely
with a good consulting engineer. If your AM tower is used to mount the
translator antenna and is in town or at the edge of town and the city of
license is what you are trying to cover, you should be in luck, as the 60 dB
contour should do pretty well. But if you are a station licensed to the little
town and you want to cover the big town down the road, you may be disappointed,
especially if you are at the high end of the dial and your AM tower is in the
150 foot range and /or in a valley.
Some stations will
have excellent results with their new translator if they can find a TV or tall
FM tower on which to lease some space on. A signal of 250 watts at 200 meters
can go a very long way — even farther if the height above average terrain
(HAAT) exceeds the tower height.
Commercial FM stations
enjoy listeners receiving well below the 60 dB signal level, and some stations
have good audience at the 40 dBu level; but DO NOT expect such performance from
your translator! Many of the new grants will be at the edge of commercial
station coverage or in low signal area between two big co-channel operations, and
you may find those stations creeping into your coverage long before you get under
50 dBu. Your enemy is interference from those big boys. Your 250 watts is no
match for heavy incoming signal.
You may also find
yourself up against another translator down the road on the same frequency, and
if that’s the case your 60 contour is going to be your realistic limit in that
Unless your station is at the bottom of the
dial under 900, you might want to look for some place other than your own tower
to locate. A good engineer can be creative. Think about water towers, taller
buildings in the business district or even a grain silo at the edge of town.
Don’t rule out sharing space on the police/ fire communications tower. Or even
the two-way system of the power company. Also check with the local amateur club
to see if they have space on a repeater tower. Some might be happy to make a
deal with the local station.
Keep in mind you can drive
your translator with an audio over IP feed (AoIP) from the Internet, so no
dedicated phone line or STL over UHF is needed to the studio. And while all of
us have tight budgets, the money you spend on a good consulting engineer can
make the difference between a great signal and huge disappointment.
This is a one-time deal so don’t screw it up. Tell your
consultant what are you really are trying to cover and he or she may have some good
ideas to get the best you can where you want it. Remember it’s not just what fits,
it’s what fits AND works best for you! Good luck.
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