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Twin Channel Amplifier: Terra at422 (VHF, analog TV & DVB-T, AGC)
Twin Channel Amplifier: Terra at422 (VHF, analog TV & DVB-T, AGC)
Twin Channel Amplifier: Terra at422 (VHF, analog TV & DVB-T, AGC)
Views of the amplifier
Twin Channel Amplifier: Terra at422 (VHF, analog TV & DVB-T, AGC)
View of the included accessories: connecting bridge, wall mount (wall installation option)
and spacer (to insert between the amplifier and an adjacent module)
Distinguishing features
  • Two independent paths (sections),
  • Amplification of two analog TV channels or two DVB-T multiplexes from the VHF-3 band (174...230 MHz, ch. 5-12),
  • AGC - automatic equalization of all channel levels to 90 dBuV (analog mode) or 85 dBuV (DVB-T mode),
  • Channel offset: -1...+1 MHz (0.125 MHz step),
  • High modulation error rate (MER): >36 dB,
  • Selectivity 40 dB at +/-1.25 MHz (analog) or at +/-2 MHz (DVB-T) from channel borders due to ultra selective SAW (Surface Acoustic Wave) filters,
  • Output level adjustment: 0...-10 dB,
  • Digital interface with buttons located on the front panel,
  • Two-position display,
  • 12 VDC / 0.1 A power for a preamplifier,
  • DIN rail mounting (usually in a 19" RACK cabinet),
  • Perfect for the transitional period when broadcasters often change the frequency and power of DVB-T multiplexes.
At422 R82509 is a double highly selective tunable amplifier capable of filtering and equalizing levels of antenna signals in VHF-3 band, in analog or digital (DVB-T) mode. The output channels/multiplexes can then be distributed in large MATV systems - in multifamily buildings, hotels, public buildings, etc. Its high modulation error rate (MER), not lower than 36 dB, provides an excellent reception of digital terrestrial TV broadcasts even in very extensive systems.
Each of the two independent paths can amplify one DVB-T multiplex or analog TV channel. It means that one module can amplify two digital multiplexes. The paths are equipped with automatic gain control (AGC) and ultra selective SAW (Surface Acoustic Wave) filters.
The module is digitally adjustable with three buttons located on the front panel. Thanks to exceptional flexibility and AGC, the device is perfect for the transitional period when broadcasters often change the frequency and power of DVB-T multiplexes.
The automatic gain control ensures:
  • automatic equalization of signal levels - for input levels within 50-80 dBuV range for digital multiplexes and 60-85 dBuV range for analog channels - to 80 dBuV (DVB-T) and 85 dBuV (analog TV). This function eliminates the need of manual adjustments of signal levels at the installation and maintenance stages;
  • automatic gain adjustment in the case of changes of transmitter parameters.
The amplifier can be powered with a 12 VDC power supply with minimum current capacity of 0.45 A (for one unit without an preamplifier). In the case of a greater number of the units, the best choice is the dedicated power supply DR-60-12 R82532. The at420 amplifier has the ability to power terrestrial TV masthead preamplifier (12 VDC, max 100 mA).
The unit can be installed on a wall (with the wall mount), or placed on universal DIN rail R82538 in a 19" RACK cabinet.
The complete Terra solution for MATV (shared antenna) systems includes a range of components that can be selected according to the current needs and requirements of customers:
  • R82510 - at420 - twin channel amplifier
  • R82511 - at440 - four-channel amplifier
  • R82515 - mt420 - twin VSB TV modulator
  • R82520 - ma400 - high-level multiband amplifier (FM/VHFIII/UHF)
  • R82532 - DR-60-12 - DIN rail power supply capable of powering up to 8 system devices
  • R82536 - 699.20 - DC distribution cable for 4 modules
  • R82538 - universal DIN rail mounting bracket matching 19-inch RACK cabinets for up to 8 system devices and power supply
  • R82540 - 699.026 - F-F coaxial bridge for signal links between adjacent modules
An example set of the amplifiers and modulators for a MATV system. For maximum stability,
the number of modules on each side of the power supply should not exceed 4 units.
Name at422
Code R82509
Number of channels (sections)
Tuning range of channels 174...230 MHz (ch. 5...12, ch. width 7 MHz)
RF input
operation mode analog digital
level/impedance [dBμV/ Ω]  60-85/75 50-80/75
frequency range [MHz] 47-862
loop-through gain [dB] 0 +/-1.5
return loss [dB] > 12
RF output
level [dBμV] 90 85
MER (digital signals) [dB] - > 36
level adjustment [dB] 0...-10 (step 1)
return loss [dB] > 10
Noise figure [dB] 8
Selectivity (analog)
40 dB at +/-1.25 MHz from channel borders -
Selectivity (DVB-T)
- 40 dB. +/-2 MHz from channel borders
Offset [MHz] +/-1 (step 0.125)
Spurious signals level [dBc] < -55 
Gain ripple [dB] +/-1.5
Power for masthead amplifier  12 VDC / 0.1 A max
Supplying voltage [VDC]  12
Current consumption [A] 0.45
Operating temperature [ºC] 0...50
Dimensions [mm] 198x107.5x36
Weight [kg] 0.9


Tip produs Channel amplifier
Nume at422
Producător TERRA
Intrare RF număr 1
Nr. de MUX-uri acceptate 2
Bandă funcționare VHF
Utilizare Interior
standard DVB-T/T2
Funcția AGC Da
Selectivitate dB 40 ± 2 MHz from the channel boundary
Intrare VHF Bandă frecvențe MHz 174...230
Câştig dB AGC
Sursa de alimentare a preamplificatorului V/A DC 12/0.1
Max. Nivel de intrare dBµV 50...80
Impedanță Ohm 75
Return loss dB >10
Ieșire RF Puterea semnalului dBµV 85
Impedanță Ohm 75
MER dB ≥ 36
controlul nivelului dB -10...0 cu pasul 1
Decalaj MHz ± 1 cu pași de 0.25
Return loss dB >10
Raportul de zgomot dB 8
combinator RF Bandă frecvențe MHz 47...862
Câştig dB 0
Configurare ecran + butoane
Sursă de alimentare incorporată Nu
Curent tras V/A DC 12/0.45
Montare RACK 19”. Da
Temp. funcționare °C 0...+50
Greutate kg
Dimensiuni mm 36 × 107,5 × 198