MODEL TFM-550
Airborne UHF and VHF High/Low band FM Transceiver
Technisonic Multi-Band VHF Lo/VHF Hi and UHF AirborneTransceiver
The Technisonic TFM-550 Multi-Band airborne VHF/UHF FM transceiver utilizes state of the art frequency synthesis techniques to
provide FM communications on every currently available channel within the General Radio Service VHF/FM Low Band, VHF/FM
High Band and UHF/FM Band. This transceiver covers VHF Low Band from 30 to 50 MHz in 2.5 KHz steps, VHF High Band from
138 to 174 MHz in 2.5 KHz increments and UHF from 403 to 512 MHz also in 2.5 KHz steps. Operating frequencies and other
related data are presented on a 96 character, four line LED matrix display, which is available in either red or green.
The TFM-550 can be installed to operate in “
Single Mode
” to function as a multi-band transceiver operating in VHF Lo, VHF Hi or
UHF bands with combined audio run through a single audio controller FM input. In this mode, the band select switch is positioned
by the operator to select one of the three bands which are accessed one at a time. Combined audio and transmit control are
available at J101 (15 pin connector) at the rear of the transceiver. Alternately, the TFM-550 can function in “
Dual Mode
” and be
installed to two FM positions (typically FM1 and FM2) on the audio controller, allowing for simultaneous operation on UHF and
either VHF Low or VHF High Band. In this mode, VHF Hi and VHF Lo audio are combined and output to a single audio controller
FM input. The front panel band select switch provides for VHF-Hi or VHF Lo transmitter selection. VHF Hi and VHF Lo audio and
transmit control functions are available at J102 (9 pin connector) at the rear of the transceiver. UHF receive and transmit
functions are totally independent and controlled via the second audio controller position allowing for simultaneous VHF (Hi or Lo)
and UHF operation. Additionally, the TFM-550 can operate as a VHF/UHF cross band repeater. The cross band function is front
panel controlled and requires only 2 key stokes to enable or disable. All data entry and control commands are entered via an
enhanced 12 button keypad situated on the face panel.
The TFM-550 can be operated in the Direct Entry or Simplex mode by simply keying in the desired operating frequency. It can
also function without restriction on any split frequency pair within any of it’s three bands. This unit features 600 preset memory
positions (200 VHF Lo, 200 VHF Hi and 200 UHF) each capable of storing a receive frequency, a transmit frequency, a separate
CTCSS tone for each receive and transmit frequency, an alpha numeric identifier for each channel and a DPL or DCS coded
squelch identifier for each channel. The TFM-550 provides for either 25 kHz wide band or 12.5 kHz narrow band operation on any
or all of it’s 600 preset channels. An upload/download function allows the operator to download channel information from a PC, or
upload stored data from the transceiver to a PC. Supporting software is supplied with each unit. Information stored in the
transceiver’s memory is available for instant recall by keypad entry or, by pressing the M.UP or M.DOWN button which allows the
operator to scroll through all preset channels. The TFM-550 transceiver also features a DTMF encoder for signaling during
transmit, and a scan function which will scan any or all of the frequencies stored in up to five scan lists. Additionally, a remote
control head is offered (RC-550) which provides for slaved operation of the main transceiver from a remote location, allowing for a
second position in the aircraft to exercise frequency control. VHF Low band, VHF High Band and UHF operating frequencies as
well as the Direct/Repeat function can be controlled from the “remote” position. Active frequency for all three bands is displayed
on both remote and local displays.
The TFM-550 transceiver is panel mounted (Dzus) and completely self contained in a 8.0 x 3.75 x 5.75 inch chassis weighing just
5.0 pounds. Front panel controls are
UHF
for UHF audio level;
VHF
for VHF High Band audio level and
VHFLO
for VHF Low
Band audio level. The
VHF/UHF/VLO
band switch enables selection of the desired band as well as providing for manual
programming, a
VHF/PRI
select switch provides for a VHF priority channel, and a
HI/LO
switch controls transmitter power output.
Twenty eight (28) volt DC backlighting is standard, (5 Volt AC is optional) and controlled by the aircraft dimmer bus. Display
brightness is controlled from the front panel keypad. RC-550 “remote control” access is via a 9 pin connector (J102) located on
the rear panel of the TFM-550 transceiver. External access for mic level adjust (sidetone is software controlled and operator
adjustable) provides for easy installation and setup for optimum performance. The small size and light weight (5.0 lbs., 2.3 Kg) of
the TFM-550 Multi- Band transceiver makes this radio ideally suited to helicopter installations. Technisonic FM radios are
compliant with RTCA DO-160C categories relating to Vibration, Overpressure, Humidity, Temperature and Altitude, Magnetic
Effect, Power Input, Voltage Spike, Decompression, and RF Emission (including DO-160C, Section 21, Category Z).
Summary of Contents for TFM-550
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