In Broadcast - August 2020 - 42

42

www.inbroadcast.com | Vol: 10 - Issue 8 | August 2020

InAudio

FM Broadcast Radio
Transmitters
Contributing Editor David Kirk tunes
in to the latest technology broadcasting
the perennial FM band to the airwaves...
CTE Broadcast Blue series FM transmitters

F

M radio broadcasting is the great
survivor, invented in 1933 by
American engineer Edwin Armstrong
to overcome the problems of static
and skywave interference inherent in
AM. Initial interest was low, both for
technical and commercial reasons,
and FM was nicknamed 'Forgotten
Medium' until the early 1960s. Then
the transition from mono to stereo
audio listening encouraged FM's
widespread adoption. FM today
remains a very popular analogue
medium in an otherwise largely digital
world. This article overviews some of
the main broadcast FM transmitter
manufacturers, focusing wherever
possible on their latest products.
Broadcast Electronics' STX LP
Series Generation II transmitters
are designed for FM analogue and
HD Radio transmission, HD Radio
being the in-band on-channel digital
technology used by many broadcasters
in Canada, Mexico and the USA. The
transmitters are available in 1, 2, 3 and
5 kilowatt versions.
An optional second controller/
exciter can be added for full control
and redundancy in the event of an
exciter or controller failure. All BE
transmitters can be operated remotely
from a phone, tablet or computer.
Crown Broadcast's 'Companion'
allows any of the company's
transmitters to be controlled via IP.
Occupying 1U, it connects via 15-pin
DBA to any pre-2007 model, providing
full monitoring but limited control.
More recent transmitters connect via
25-pin DBA and support full monitoring
and full control. Capabilities include
remote metering, silence detection
with email alerts, and long-term
logging of transmitter parameters.

Broadcast Electronics
STX LP Series Generation II

CTE Broadcast's Blue series FM
transmitters are designed to allow
easy access to components such
as air cooling filters. The company
claims a long mean time between
failure for its RF modules and power
supply modules. The transmitters are
stabilised by a digital phase-locked
loop; a 10 MHz external reference
oscillator is available as an option.
Input sensitivity and output deviation
can be adjustable in 0.05 dB steps
from a touch screen display on the
front panel. An adjustable modulation
limiter keeps the maximum frequency
deviation
in
compliance
with
international requirements. Options
include an AES/EBU digital stereo
audio input, web server SNMP, GSM or
SMS remote control and WiFi remote
control.
DB Elettronica's
Mozart
FM
transmitter is available in 1, 2, 3, 3.5,
6 and 7 kilowatt versions. Frequency
range is 87.5 to 108 MHz, adjustable
in 10 kHz steps from the LCD front
panel. The integral stereo generator
is claimed to provide >65 dB channel
separation and >80 dB signal to
noise ratio. A limiter keeps the
maximum frequency deviation within
international requirements to avoid
over-modulation and adjacent channel
interference. Limiter levels can be set
from the front panel. Complete web
server SNMP, GSM or SMS remote
control are available as option.
Eddystone's S79005 500 watt FM
transmitter provide the modularity of
the company's S7600 series in a more
compact and cost effective package.
E2021 300W hot-pluggable power
amplifier modules allow removal
of amplifiers to be carried out with
minimal reduction in output power.

The drive input is fed to an internal
two-way splitter which provides the
power amplifier module input drive.
Each E2021 power amplifier uses
dual packaged MOSFETs mounted
on a heatsink. DC power is fed to the
RF modules from one (optionally
two) switched-mode power supplies.
Internal control and self-protection
in case of reverse power, excess
current or over temperature are
handled within each individual E2021
power amplifier module. Each module
transmits its internal parameters to
the central transmitter controller/
monitor for viewing on a back-lit LCD.
Redundant cooling fans are mounted
on the rear of the transmitter. Cooling
can be ducted if required and bespoke
systems are available to meet special
requirements.
Elenos' ET10000x comprises a 10
kilowatt FM radio transmitter in 4U
plus a 2U modulator. Available with
analogue or digital modulation, it has
a claimed 70 per cent efficiency when
used at full power. Features include
modular construction, lightweight,
integral diagnostics and an internal
protection system.
Elettronika SRL's DATxF line of
FM transmission amplifiers can be
configured by combining 3 kilowatt
or 5 kilowatt modules, each of which
functions fully independently. The
resultant system includes automatic
protection against failure. Full web
based or SNMP based remote control
is possible.
Eurocaster's DDS 1000 digital FM
radio transmitter occupies a 3U chassis
and has a maximum output power of
1 kilowatt. Features include analogue,
multiplex, AES/EBU and AES192 inputs,
a Micro SD card port, RDS encoding,

DB Elettronica's
Mozart - 1 to 7 KW transmitters

event logger and IP or SNMP remote
control.
GatesAir has broadened its range
of Maxiva transmitters with the
introduction of the VLX-OP series.
This product line covers low-band
VHF (channels 2-6), high-band VHF
(channels 7-13), and DAB/DAB+ radio.
The VLX-OP series offers the same
software-defined modulations as
Maxiva VAXTE air-cooled transmitters
to support global analogue and digital
standards. Like GatesAir's Maxiva
ULXTE liquid-cooled UHF transmitters,
the
VLX-OP
series
integrates
redundant liquid-cooling pumps that
move transmitter-generated heat to
building exteriors. The transmitters
operate at the same power level for
ATSC 1.0 and ATSC 3.0 broadcasts (1.8
to 43 kilowatt).
Nautel's MP11 GV series FM
transmitters now support the MP11
enhanced data mode. This provides
higher HD Radio data rates, allowing
additional audio and data services
such as traffic reporting. "With an
increasing number of HD Radio
receivers in the field, many stations
that have converted to digital are
continuing to build out more HD
multicast side channels," says Philipp
Schmid, Digital Systems Team Lead at
Nautel. "Many have already adopted
the extended service mode MP3 as
a way of increasing IBOC payload
capacity by 24 kbps, permitting
an additional audio service or
datacasting. MP11 offers even more
payload capacity by placing additional
extended carriers closer to the FM host
signal." Nautel's latest transmitter
software update adds MP11
Elenos' ET10000x 2U Modulator and
4U 10 kilowatt FM radio transmitter
http://www.inbroadcast.com https://ctedb.com/ https://www.elenos.com/et10000x-fm-transmitter/ https://www.elenos.com/et10000x-fm-transmitter/ https://www.dbbroadcast.com/ http://www.bdcast.com
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