This document provides installation and operation instructions for Pico Macom's single-channel amplifiers, including models LBS, FMS, MBS, HBS, UBS, 72L, 72M, 72H, and 72S. These devices are designed to boost the amplitude of individual TV signals derived from an antenna or converter, ensuring a quality Private Cable system.
Function Description:
Pico Macom single-channel amplifiers are crucial components for optimizing television reception in private cable systems. They take a low-level input signal from an antenna or converter and amplify it to a usable output level, preventing signal distortion and ensuring clean pictures. The amplifiers are designed to operate with various antenna setups, including broadband, single-channel Yagi, or a combination of both, depending on signal strength and direction. They feature Automatic Gain Control (AGC) to maintain a consistent output level despite variations in input signal strength, and an adjustable sound trap to control the audio carrier amplitude. The units are designed for 1.75" low-profile rack mounting and include an AC convenience outlet for chaining multiple amplifiers in a head-end rack.
Important Safety Instructions and Safeguards:
Before installation, users are advised to read all safety and operating instructions. Key warnings include:
- Product Inspection: Inspect for shipping damage and file a claim with the carrier if found.
- Electrical Safety: To reduce the risk of fire or electric shock, do not expose the appliance to rain or moisture, and do not open the cabinet. Refer servicing to qualified personnel only. The lightning flash symbol warns of uninsulated "dangerous voltage," while the exclamation point alerts to important operating and maintenance instructions.
- Polarized Plug: Use the polarized plug correctly to prevent electric shock. If it doesn't fit, contact an electrician.
- Water and Moisture: Do not use near water sources like bathtubs, sinks, or swimming pools.
- Ventilation: Ensure proper ventilation. Do not block cabinet openings or place the product near heat sources.
- Grounding: The product is equipped with a polarized plug and should be operated from the specified power source. Outdoor antenna systems must be properly grounded to protect against voltage surges and static charges, following National Electrical Code (NEC) guidelines (Article 810 for radio and television equipment, and Article 820-22 for CATV systems). Grounding involves using specific wire gauges (e.g., No.10 AWG copper) and securing wires with stand-off insulators.
- Servicing: Do not attempt to service the product yourself. Refer all servicing to qualified personnel, especially if the power cord is damaged, liquid has spilled, the product has been exposed to water, it operates abnormally, or the cabinet is damaged.
Antenna Selection and Signal Combining Methods:
The choice of antenna depends on signal strength and direction. A site survey with a field strength meter is recommended.
- Broadband Antennas: Used in areas with moderate to strong signals from the same general direction. A mast-mounted, low-noise pre-amplifier (e.g., MPA-25) is recommended to boost input levels to over 20 dBmv. Signals are separated into UHF and VHF bands using a UVSJ separator, with a DC-20 directional coupler for a test point. UHF signals are split with DSU-* series splitters, and VHF signals are band-separated with an HLSJ hi/low separator, then split with DSV-* high isolation splitters.
- Single Channel Yagi Antennas: Used for weaker signals coming from opposite directions. These are cut to specific channels for higher gain. A single-channel pre-amplifier may be needed for very weak signals (outside 60 miles).
- Combination Broadband & Single Channel Yagis: Common in areas with variable signal levels and multiple signal directions.
Signal Combining Methods:
The document illustrates three methods for combining strip amplifier, modulator, and processor outputs:
- PHC-12 Combiner: Consists of two rows of directional couplers combined by a hybrid splitter, providing high isolation (40 dB) between inputs. Odd channels are combined on one row, even channels on the other. Combiner loss is 16 dB per channel.
- CHC-16 Combiner: Combines signals and provides post-amplification. It's a passive combiner and a CA30 amplifier in one package, combining up to 16 signals with a gain of 15 dB per channel.
- Hybrid Splitters: Uses three hybrid splitters per head-end rack. Odd channels are combined in one splitter, even channels in another, and these two are combined into a single output with a third splitter, which then connects to a CA-30 post amplifier.
Important Technical Specifications:
- Output Power: Maximum output before signal distortion. Industry standard levels are 66 dBmv (2 volts) or 72 dBmv (4 volts).
- Gain: Amount of amplification available. 66 dBmv units require 12 dBmv input for 54 dB gain; 72 dBmv units require 10 dBmv input for 62 dB gain.
- Automatic Gain Control (AGC): Ability to maintain constant output power despite input level variations. AGC stiffness is ±1 dB for 30 dB input change, with an AGC range of +4 to +40 dB. Front panel AGC adjust range is 15 dB.
- Input Noise Figure: Lower numbers indicate better performance at low input levels. LBS/MBS/HBS/72L/72M/72M have 6 dB, 72S has 7 dB, and UBS has 9 dB.
- Gain Selectivity: Amplifier's ability to amplify only the desired channel. Pico Macom amplifiers have sufficient filtering for adjacent modulators. Bandpass filters are used under strong channel "skip" or strong alternate channel conditions.
- Aural Carrier Reduction: Reduces audio carrier amplitude to allow higher video carrier levels. NTSC audio quality is maintained even at 17 dB below the video carrier. Sound trap is adjustable from 0 to -10 dB.
- Bandwidth (±.5 dB flatness): 6 MHz for LBS/MBS/HBS/UBS/72L/72M/72S. FMS is (88-108) MHz or (92-108) MHz switchable.
- Maximum Output Level (@ .5 dB sync compression): 66 dBmv for LBS/FMS/MBS/HBS/UBS; 72 dBmv for 72L/72M/72M/72S.
- Skirt Selectivity: Measures rejection of adjacent frequencies. For LBS/MBS/HBS/72L/72M/72H, F center ± 6 MHz is -40 dB, F center ± 9 MHz is -50 dB. For 72S, F center ± 6 MHz is -30 dB, F center ± 9 MHz is -45 dB. For UBS, ±3 Channels is -50 dB, ±6 Channels is -65 dB. For FMS, Wide - Channel 5 is -40 dB, Narrow - Channel 6 is -20 dB.
- Input Return Loss: 10 dB.
- Output Return Loss: 15 dB.
- Power Requirements: 108 to 120 VAC, 60 Hz, 10 W.
- Mounting: 19" single rack space.
- Line Cord: 3 wire grounded, 3 wire convenience outlet.
- Operating Temperature: -10 Deg to +50 Deg C.
- Finish: Plated.
- Dimensions: 19" L x 2.875" D x 1.75" H.
- Weight: 3.75 lbs.
Usage Features:
- Front Panel Controls:
- Model Number: Identifies frequency band and output power.
- Power On LED: Indicates power status.
- Output Test Monitor (-30 dB): For system alignment.
- RF Gain, AGC: Potentiometer to control RF output level and AGC threshold.
- Aural Level: Tunable notch filter to adjust audio carrier level.
- Input Test Monitor (-20 dB): To monitor antenna signal level.
- Rear Panel Connectors:
- IN (F connector): Connects to broadband or Yagi antenna.
- OUT (F connector): Provides amplified signal.
- THRU (F connector): For coupling outputs of other non-adjacent strip amplifiers.
- Convenience Outlet (250 watts max): For chaining amplifiers in a rack.
- Power Cord: Three-prong polarized cord (UL and CSA approved) for 108-125 VAC, 50/60 Hz. Do not cut the ground terminal.
Maintenance Features (Bench Alignment):
The manual provides a detailed bench alignment procedure using a sweep generator system, external marker generator, TV signal generator, and spectrum analyzer (e.g., Wavetek 1076, 1081, 1901; Agile Modulator; Sencore VA-62; HP 8558B/182T).
- Plug the unit into a 108-125 Vac outlet.
- Set sweep generator center frequency to the desired channel.
- Connect TV signal generator/agile modulator to sweep generator external marker input.
- Set sweeper output level below AGC input range (-10 dBmv for 72* models, 0 dBmv for *BS models).
- Adjust C11 to move the audio notch to the upper channel edge.
- Coarse tune amplifier and output filters by adjusting C1, C3, C6, C8, C10.
- Fine tune filters by adjusting C1, C2, C3, C6, C7, C8, C9, C10 for a desired response curve.
- Connect sweep generator to "Thru" and "Out" connectors. Adjust bandstop thru filter C4 and C5 for a desired response.
- Connect TV signal generator to input and spectrum analyzer to strip amplifier output.
- Adjust front panel Aural Level to locate the notch at the lowest frequency, then adjust C11 to the audio carrier.
- Set front panel RF gain AGC control to minimum gain (maximum AGC).
- Vary input level from +4 dBmv to 30 dBmv and verify constant output level (LBS: 54 dBmv ± 2 dB; 72L: 62 dBmv ± 2 dB).
- Set RF gain AGC control to maximum gain (minimum AGC).
- Vary input level from +12 dBmv to 40 dBmv and verify constant output level (LBS: 54 dBmv ± 2 dB; 72L: 62 dBmv ± 2 dB).
Warranty:
Pico Macom Inc. offers a Five Year Limited Warranty to the original purchaser, covering defects in material and craftsmanship. During this period, Pico Macom or an authorized service facility will provide free parts and labor. The warranty terminates if the product is misused, damaged due to neglect or improper installation, modified, repaired by unauthorized personnel, or sold by the original purchaser. To obtain service, contact the salesperson where the product was obtained to receive a Return Authorization (RA) number. The RA number must be clearly indicated on the shipping label. The warranty requires providing the model number, channel number, date of purchase, and a specific problem description. This warranty constitutes Pico Macom's entire obligation and excludes claims for incidental or consequential damages.
To Next Page
Need help?
General
