Bext Radio Transmitters

  • Solid StateLEX 1RU compact FM exciter                   

LEX 30, 50, 100                

  • 30, 50 or 100 Watts of Frequency Agile FM Power in a one rack space, ultra compact size
  • Built-in, selectable high separation internal Stereo Generator, standard
  • Fast access to all functions & parameters from front panel via user-friendly menu display
  • Instant frequency programmability directly from software
  • Proportional Auto-Foldback of output power in the event of excessive VSWR
  • Adjustable power output from 0 to full power. with soft-start control
  • Automatic power control maintaining the output at any pre-set level
  • Modular layout with plug-in, easily replaceable circuits and parts
  • Voltage selector for 120 or 230 V operation
  • Built in programmable FSK ID Keyer
  • Meets or exceeds all FCC and CCIR requirements
  • Includes low pass/harmonic filter and can be used as a stand-alone transmitter
 
RF SPECIFICATIONS

Nominal RF power:

30, 50 or 100 W adjustable from 0.5W to full power

RF output impedance:

50 Ohms unbalanced, VSWR less than 1.5:1

RF connector:

N Type Female
Frequency range: 87.5-108 MHz programmable in 10 kHz steps, synthesized,  microprocessor controlled

Off lock attenuation:

> 60 dBc

Lock-in time:

< 20 sec. (typ. < 7 sec)

Type of Modulation:

F3E / F8E direct FM at carrier frequency

Frequency deviation: 

+/- 75 KHz = 100%, +/- 150 kHz capability
Reference:

12.8 MHz VTCXO

Stability of freq. dev:

+/- 2,5 % x 6 mo.

Consistency of deviation over range:

< +/- 2 % from 87.5 to 108 MHz

Frequency drift:

< / - 2 kHz/year (due to internal TCXO aging). Can be user calibrated

Short term stability:

+/-  1 ppm from -5 to +45 C (100 Hz @ 100 MHz)

RF Harmonics:

Exceeds EBU/ CCIR/FCC requirements >70 dBc

RF Spurious: 

Exceeds EBU/ CCIR/FCC requirements, < -90 dBc min @ +/- 1 MHz

RF Monitor:

-40 dBc+/-3 dB from 87.5 to 108 Mhz (not suitable for measuring harmonics)
AUDIO GENERAL SPECIFICATIONS

Preemphasis: 

Flat/50/75 microseconds, microprocessor controlled

Preemphasis precision:

better than 0.5 dB

Stereo System:

CCIR / FCC "pilot tone system"

Distortion, THD:

Less than 0.1% (typ. 0.05%)

Intermodulation (IMD):

Less than 0.1%(typ. 0.05%)

Transient IMD:

< 0.25 % (square / sine Wave)

Wideband Amplitude Response:

+/- 0.25 dB, 30 Hz to 100 kHz

Audio Filter Attenuation: 

> 50 dB @ 19 kHz, >30 dB 19 to 50 KHz, >50 dB to 100 kHz (typ.)

Common mode rejection:

> 40 dB typ. 30 Hz to 15 kHz (50 dB on request)
COMPOSITE SPECIFICATIONS
Stereo Separation: 30-80 Hz > 50 dB, 80 Hz-15 kHz > 60 dB (typ.65)
Crosstalk attn. (M / S): > 40 dB 40 Hz to 15 kHz (typ. 50 dB / 100 Hz to 8 kHz)
Audio Spurious Products:  > 53 kHz < 50 dB
38 kHz Suppression:  > 50 dB
38 kHz Tone Generation:  Internal Crystal
38 kHz tone Precision: 38 kHz +/- 2 Hz
Pilot Tone frequency: 19 kHz +/- 1 Hz
Phase response: 19/38 kHz 0 degree +/- 2 degrees internally adjustable
THD on L & R channels:  <0.1% 30 Hz - 15 kHz
IMD: 70 Hz / 6 kHz 4:1 RATIO <0.1%
Transient IM: <0.25% (square / sinus)
Audio response: +/- 0.25 dB 20 Hz to 15 kHz
Pilot Tone Deviation:  +/- 7 kHz nominal
S/N: Typical Values referred to +/- 75 kHz: Weighted (CCIR 468/2- Peak CCIR detector) 80 dB / 50 microseconds - 74 dB / flat   Weighted (CCIR 468/2 - RMS detector) 83 dB / 50 microseconds - 77 dB / flat  Unweighted (RMS detector, 30 Hz-20 kHz) 80 dB / 50 microseconds - 71 dB / flat
AM Synchronous:  (AM = 500 Hz, FM = 500 Hz +/- 75 kHz Ref. = 100 % AM, RMS detector, BW 30 Hz-200 kHz) < -55 dB typ. -60dB
AM Asynchronous: FM = no modulation, Ref. = 100 % AM, Unweighted, RMS detector, BW 30 Hz- 200 kHz) < - 55 dB typ. -60 dB
Am asynchronous:  (Fm = no modulation, Ref. = 100 % AM, Unweighted, RMS detector, BW 30-200 kHz) < -68 dB, typ. -80 dB
AUDIO INPUTS

SCA / RDS Input: 

1 BNC connector, unbalanced, Z nominal~3 kOhm (2.8<Z<3) Lev: -3 + 6 dBm @ 7.5 kHz, Dev. adj. on rear panel
AUX Input:

1 BNC conn, nbal., Z nominal ~ 3 kOhm (2.8<Z<3) Lev: -3 + 6 dBm @ 7.5 kHz Deviation adj on rear panel
MPX Input: 

1 BNC conn., unbalanced, Z nominal ~ 1 k2 (1 k2 +/- 10 %), Lev: -3 + 6 dBm @ 75 kHz Deviation, adj. on rear panel
L & R + Mono Input:

2 XLR connectors, balanced or unbalanced; Z nominal 10 kOhm +/- 1 % or 600 Ohm +/- 1 %; uP selectable by menu; uP selectable Lev: -3 + 6 dBm @ 75 kHz Deviation. Coarse steps 3 dB (uP) Fine adj. 3.5 dB (+/- 1.75), adj. on rear panel
OTHER CONNECTORS
19 kHz Output:  1 BNC connector, unbalanced Z nominal: > 5k Pilot = 1 Vpp 19 kHz Squarewave
Status of correct output:  1 BNC connector, unbalanced, 15 Vmax, 100 mA (open drain)
Interlock: 1 BNC connector, unbalanced, Normally open or normally closed, selectable by internal jumper
RS 232: DB9 on front panel (firmware update)
RS 485: RJ45 custom pin-out connector
ENVIRONMENTAL
Storage temperature: -20 C to +60 C
Operating temperature: 5 C to 45 C
Guaranteed performance temp: 0 C to +40 C
Relative humidity: 90% (non condensing)
Max operating altitude: 2000 m.
Cooling: Forced air (internal low noise blower)
PHYSICAL & ELECTRICAL
Front Panel: 483 mm (19") Wx 44mm (1 3/4") H (One standard rack space high)
Overall Depth:  365 mm (14")
Weight: Approx. 4 kg (8.8lbs)
Cabinet: Stainless steel
AC Power: 120 / 220V AC single phase (+/- 15 %), 50 - 60 Hz; Internal voltage selector
LCD Display Readings: Programmed Output Power; Forward Power; Refl. Power; Unclipped Deviation (simulated Led Bar); Clipped Deviation (simulation Led Bar); Clipper activity (clipped / unclipped differential); L Audio True Peak Level (simulated Led Bar); R Audio True Peak Level (simulated Led Bar); Frequency (6 digits); Sensitivity (3 dB step); RDS, SCA, AUX, MPX Ext Modulation; Programmed Audio Parameters; Preemphasis (Flat, 50, or 75 microseconds); Limiter On / Off; Input Impedance; Z = 10 kOhm / 600 Ohm; Preset Thresholds (min. RF power, mute time)

(c) 2004 BEXT Corporation USA